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Allocation of nonstructural carbohydrates for three temperate tree species in Northeast China

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植物生态学报 2011, 35 (12): 1245–1255 doi: 10.3724/SP.J.1258.2011.01245
Chinese Journal of Plant Ecology http://www.plant-ecology.com
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收稿日期Received: 2011-06-17 接受日期Accepted: 2011-09-09
* 通讯作者Author for correspondence (E-mail: wangck-cf@ nefu.edu.cn)
三种温带树种非结构性碳水化合物的分配
于丽敏 王传宽* 王兴昌
东北林业大学生态研究中心, 哈尔滨 150040
树体中的非结构性碳水化合物(NSC)浓度、含量及其分配反映了树木整体的碳供应状况, 是决定树木生长和存活的
关键因子, 也是构建树木碳平衡模型的关键参数。温带树种的NSC尚缺乏系统研究。该文测定了特性各异的3种温带树种在
生长盛期的NSC及其组分的浓度和含量以及分配格局的种间种内变异。结果表明, NSC及其组分的浓度在树种和组织之间差
异显著, 可溶性糖、淀粉和总NSC浓度分别在0.65–8.451.96–5.953.00–13.90 g·100 g–1 DM之间波动。NSC及其组分含量的
大小依次为: 兴安落叶松(Larix gmelinii) >蒙古栎(Quercus mongolica) >红松(Pinus koraiensis), 其中叶和根中的浓度较高。树
干中的NSC及其组分浓度的纵向变化不显著, 但其心材与边材之间的浓度差异却随树种和NSC组分而异, 表现为心边材的可
溶性糖浓度差异不显著, 但其淀粉和总NSC浓度差异显著。不同直径根系的NSC及其组分浓度在2种针叶树种中差异不显著,
但在蒙古栎中差异显著。蒙古栎将可溶性糖主要投资到地上生长, 2种针叶树将更多的可溶性糖投资到根系生长。淀粉的
主要储存库为树干, 其在树体内的分布格局与可溶性糖正相反, 因而使总NSC在树根和树枝中的分配趋于较平衡状态。在树
干中, 除了2种针叶树的可溶性糖库以边材为主外, 心材是淀粉和总NSC的主要储存库。在树根中, 粗根是NSC及其组分的优
势储存库。该研究中3种温带树种的NSC及其组分的浓度和含量的种间和种内变化, 反映了这些树种的生长对策和体内碳源
汇强度的差异。
关键词 碳分配, 兴安落叶松, 红松, 蒙古栎, 可溶性糖, 淀粉
Allocation of nonstructural carbohydrates for three temperate tree species in Northeast China
YU Li-Min, WANG Chuan-Kuan*, and WANG Xing-Chang
Center for Ecological Research, Northeast Forestry University, Harbin 150040, China
Abstract
Aims The content and allocation of nonstructural carbohydrates (NSC) in trees reflect whole-tree carbon balance
regimes, and are crucial to determine growth / survivorship trade-off of trees and model tree carbon balance be-
tween uptake and investments in structure or loss. Our objective was to examine the concentration and allocation
patterns of NSC for three temperate tree species, i.e., Korean pine (Pinus koraiensis), Dahurian larch (Larix
gmelinii) and Mongolian oak (Quercus mongolica).
Methods During the mid-growing season (July of 2010), all biomass tissues, including foliage, branch, stem and
root, were randomly sampled from three dominant trees for each species. The stem samples were taken from
mid-canopy and breast height, and divided into sapwood and heartwood, while the root samples were divided into
fine (diameter < 2 mm), medium (2–5 mm) and coarse roots (>5 mm). All samples were dried, ground, and ana-
lyzed for NSC concentrations (including soluble sugar and starch) with a modified phenol-sulfuric acid method.
Important findings The concentrations of NSC and its component differed significantly among species and tis-
sues. Concentration ranges were 0.65–8.45, 1.96–5.95 and 3.00–13.90 g·100 g–1 DM for soluble sugar, starch, and
NSC, respectively. On average, the contents of NSC and its components followed the order of: larch > oak > pine.
Concentrations in the foliage and roots were higher than those in other tissues. Within the stems, the longitudinal
variations in the concentrations of NSC and its components were insignificant, whereas the differences between
sapwood and heartwood varied with species and NSC components. There was no significant difference in soluble
sugar concentration between sapwood and heartwood, but significant differences in starch and total NSC concen-
tration. The concentrations of NSC and its components varied insignificantly with root diameters for larch and
pine, but significantly for oak. Oak invested more soluble sugar to aboveground growth, whereas the two conifers
did more to roots. Nevertheless, starch was mainly reserved in stems, and the intra-tree allocation pattern of starch
1246 植物生态学报 Chinese Journal of Plant Ecology 2011, 35 (12): 1245–1255
www.plant-ecology.com
exhibited an opposite trend to soluble sugar, leading the total NSC to be relatively balanced between roots and
branches. In the stems, heartwood was the major reserve of NSC and starch, while sapwood was the major reserve
of soluble sugar for the two conifers. In the roots, coarse root was the dominant reserves of NSC and its compo-
nents. We concluded that the inter- and intra-specific variations in the NSC and its components in this study re-
flect differences in growth strategies and within-tree carbon source / sink strength for the three temperate tree spe-
cies.
Key words carbon allocation, Larix gmelinii, Pinus koraiensis, Quercus mongolica, soluble sugar, starch
碳水化合物是树木光合作用的主要产物, 通常
可分为结构性和非结构性碳水化合物(NSC) (潘庆
民等, 2002)NSC是树木碳水化合物在生产过剩时
积累的暂时储存(Kozlowski, 1992), 是树木生长代
谢过程中重要的能量供应物质(Koch, 1996)和必需
的临时溶质库(运输、代谢和渗透等需求物), 其浓度
和含量的大小通常可以反映植物整体的碳供应状
(Chapin et al., 1990), 体现树木阶段性碳获取和
支出的平衡关系(Poorter & Kitajima, 2007), 表征树
木生长和存活能力以及对外界干扰的缓冲能力
(Würth et al., 2005; Myers & Kitajima, 2007)因此量
NSC储量对树木碳平衡的贡献是理解树木存活
和生长的关键(Barbaroux et al., 2003)
碳水化合物分配是树木许多生态生理过程综
合作用的结果, 该分配策略将最适于树木在森林群
落中竞争、繁殖、生长和存活(Schulze, 1982)。因 此 ,
影响树木生长和存活的所有环境和遗传因素最终
都会影响到NSC的分配(Cannell & Dewar, 1994)。糖
和淀粉占NSC总量的90%以上(Hoch et al., 2003)
糖积累到较高水平时, 糖将转化为淀粉的形式积累
下来; 而当糖含量较低时, 淀粉又可转化为糖(Latt
et al., 2001)。尽管温带树种有相似的NSC利用和储
存趋势(Latt et al., 2001), 但是落叶树种和常绿树种
在固碳模式、可溶性糖和淀粉的比例以及在树木内
部的分配和循环等细节上可能不同(Dickson,
1989)。对于这个问题的研究还很少。
树木碳分配策略还依赖于其生长发育阶段(
幼龄期、幼林期和成熟期的开花阶段、结果阶段和
衰退阶段; Schulze, 1982)。以往对NSC的研究大多
以幼树为对象, 集中研究其季节动态、碳分配对防
卫和储存的贡献等, 而且多数研究仅对树木局部组
织取样(Bonicel et al., 1987; Sauter & van Cleve,
1994; Witt & Sauter, 1994; Kobe, 1997; Hoch et al.,
2003; Landhäusser & Lieffers, 2003; Myers & Kita-
jima, 2007; Poorter & Kitajima, 2007; Merchant et al.,
2010), 缺乏对成年树木整体NSC配的系统认识,
尤其缺乏对根系NSC的研究。
为此, 本文以东北东部温带森林3种特性各异
的主要树种——落叶阔叶树蒙古栎(Quercus mon-
golica)落叶针叶树兴安落叶松(Larix gmelinii)和常
绿针叶树红松(Pinus koraiensis)为研究对象, 对其
各种组织(包括叶、枝、干和根)同步取样, 比较分析
这些树种在生长盛期的NSC及其组分(可溶性糖和
淀粉)的浓度, 旨在探索树木个体水平上NSC及其
组分的浓度、含量以及分配格局, 阐明温带树种碳
代谢和生长对策的差异, 为温带树木生理生态学和
森林碳循环研究提供科学数据和理论基础。
1 实验材料和方法
1.1 研究地概况
研究地位于黑龙江帽儿山森林生态站(45°24
N, 127°40 E), 平均海拔400 m , 平均坡度10°–15°,
地带性土壤为暗棕色森林土。气候属于大陆性季风
气候, 年降水量629 mm, 72%的降水集中于6–8;
年蒸发量864 mm; 年平均气温3.1 , 1月平均气温
–18.5 , 7月平均气温22.0 ; 无霜期为120–140
天。现有植被是原地带性植被——阔叶红松林屡遭
人为干扰后演替成的天然次生林和人工林, 代表着
东北东部山区典型的森林林型(Wang, 2006)
1.2 研究材料与取样
以该地区3种特性各异的主要组成树种——
古栎、兴安落叶松、红松为对象。为了尽可能减小
树木在林分中所受光照条件的影响, 针对每种树木
分别随机选取优势木3, 在树木生长盛期(2010
7月上中旬)分别对树叶、树枝、树干和树根等组织
取样, 测定其NSC及其组分的浓度。所测样木及其
所在林分特征见表1
人工爬上样树树冠, 采用高枝剪自树冠南向
于丽敏等: 三种温带树种非结构性碳水化合物的分配 1247
doi: 10.3724/SP.J.1258.2011.01245
上、中、3个冠层随机获取样枝, 其树叶和树枝,
均匀混合后作为树叶和树枝样品。采用内径5 mm
生长锥分别在南向胸高(离地面1.3 m)和冠中处各
钻取深至髓心的树芯3, 在野外立即根据树芯的
颜色和透明度将其边材与心材分开, 作为树干样
品。采用挖掘法, 一般在5–30 cm深度的土层获取树
根样品, 洗净后按照其直径大小分为粗根(>5 mm)
中根(2–5 mm)和细根(<2 mm), 作为树根样品。所有
样品获取后在野外立即置于冷藏箱(0–4 )保存,
于当日带回实验室用微波炉杀青90 s (Hoch et al.,
2003); 所有样品均在75 恒温箱中烘至恒重;
碎过筛后备样, 以作NSC分析。
1.3 样品分析
本文将NSC定义为可溶性糖(葡萄糖、蔗糖、
糖等)和淀粉的总和(Hoch et al., 2002)。可溶性糖和
淀粉的浓度采用改进的苯酚浓硫酸法测定(Buysse
& Merckx, 1993)
蔗糖标准液的配制: 将分析纯蔗糖在80
温箱中烘至恒重, 称取0.1 g样品(精确至0.0001 g),
加少量水溶解后转入100 mL容量瓶中, 并用蒸馏水
定容成不同浓度的蔗糖标准液。
可溶性糖的提取: 称取粉碎干样60 mg, 加入
80%乙醇10 mL, 萃取24 h后用4 000 r·min–1离心10
min, 将离心后的上清液倾入适当的容量瓶; 在残
留沉淀物中再加入80%乙醇5 mL, 继续离心5 min,
获取上清液; 定容后即可用于可溶性糖浓度测定。
淀粉的提取: 将上述提取后的残余物烘干后,
加入蒸馏水10 mL; 混匀后置于沸水浴糊化15 min;
冷却至60 以下, 加入0.5%的淀粉酶溶液1 mL,
置于60 恒温水浴锅保温1 h, 加热至沸腾, 使
酶失活; 然后2000 r·min
–1离心5 min, 压滤、定容后
即可用于淀粉浓度测定。
可溶性糖和淀粉浓度测定: 取含20–80 μg糖溶
1 mL, 转移到玻璃管中, 加入1 mL (溶于80%
醇的) 28%苯酚溶液, 然后立即将5 mL浓硫酸加入
液面, 摇晃玻璃管1 min, 静置15 min, 采用紫外可
见分光光度计(T6新世纪, 北京普析通用仪器有限
责任公司, 北京), 490 nm处测吸光值, 再根据蔗
糖的标准曲线计算出可溶性糖和淀粉的浓度。
1.4 数据分析
树木各个组织中NSC及其组分含量由其生物
量和NSC及其组分浓度的乘积获得。树叶、树枝、
树干和粗根的生物量采用该林分中这3种树种的异
速生长方程(Wang, 2006)测算获得。心材和边材生
物量由上述测得的树干生物量乘以心材或边材占
树干生物量的比例获得, 其中该比例由其体积和密
度的乘积获得。心材和边材的体积采用相应的基于
胸径的异速生长方程(Wang et al., 2010)获得; 心材
和边材密度则采用钻取的树芯的体积和干重计算
获得。树皮生物量占树干总生物量的比例采用东北
地区以往相关文献(詹鸿振等, 1990; 刘世荣等,
1992; 刘志刚等, 1994; 王德义等, 1998; 尹守东,
2004; 李雪莹, 2005; 胡海清和郭福涛, 2008; 鲍春
生等, 2010)获得的平均值, 即红松为8.4%, 兴安落
叶松为12.5%, 蒙古栎为15.4%。中根和细根生物量
占总生物量的比例较小, 采用了该林分以往的测定
数据(Zhang & Wang, 2010)树干和根系的浓度采用
加权浓度。为了消除树木个体大小对比较不同树种
NSC及其组分含量的影响, 在计算个体生物量时,
将所有树种标准化为统一胸径(30 cm)采用方差分
(ANOVA)LSD多重比较不同树种和组织中
NSC的浓度和含量的所有差异的显著性。所有的统
1 样木及其所在林分的基本特征
Table 1 Basic characteristics of the sampled trees and stands
DBH, diameter at breast height
树种
Species
叶性状
Leaf trait
林分密度
Stand density
(tree·hm–2)
坡度
Slope
(°)
坡向
Slope aspect
平均胸径
Mean DBH
(cm)
平均树高
Mean tree height
(m)
蒙古栎
Quercus mongolica
落叶阔叶
Deciduous broadleaved
2 495 23
South
41.2 17.0
兴安落叶松
Larix gmelinii
落叶针叶
Deciduous coniferous
1 823 2
西南
Southwest
35.6 27.7
红松
Pinus koraiensis
常绿针叶
Evergreen coniferous
2 683 8
西
West
31.2 18.4
1248 植物生态学报 Chinese Journal of Plant Ecology 2011, 35 (12): 1245–1255
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计分析均采用SPSS 15.0统计软件完成。
2 结果
2.1 非结构性碳水化合物的树种和组织间差异
树种、组织及其交互作用显著地影响可溶性
糖、淀粉和总NSC的浓度(2)可溶性糖浓度波动
0.65 (红松树干)8.45 g·100 g–1 DM (兴安落叶松
)之间(1), 其中, 兴安落叶松的加权浓度最高
(2.97 g·100 g–1 DM)、红松次之(2.82 g·100 g–1 DM)
蒙古栎最低(2.04 g·100 g–1 DM)。淀粉浓度波动在
1.96 (蒙古栎枝)5.95 g·100 g–1 DM (蒙古栎根)
, 其中以兴安落叶松的加权浓度最高(3.58 g·100
g–1 DM)、蒙古栎次之(2.66 g·100 g–1 DM)、红松最
(2.63 g·100 g–1 DM)。总NSC浓度波动在3.00 (
松树干)13.90 g·100 g–1 DM (落叶松根), 其中以
兴安落叶松的加权浓度最高(6.55 g·100 g–1 DM)
松次之(5.45 g·100 g–1 DM)、蒙古栎最低(4.70 g·100
g–1 DM)从组织平均值来看, 树干的可溶性糖、
粉和总NSC平均浓度均最低, 分别为0.902.39
3.29 g·100 g–1 DM; 树叶的可溶性糖和总NSC平均
浓度最高, 分别为7.1110.65 g·100 g–1 DM, 而树
根的淀粉平均值最高(4.72 g·100 g–1 DM)3种树种
树干中NSC组分均以淀粉为主; 叶中NSC组分均以
可溶性糖为主; 而根系和树枝中的NSC组分因树种
而异, 其中兴安落叶松和红松根系中的NSC组分以
可溶性糖为主, 蒙古栎根系中的NSC组分则以淀粉
为主。3种树种从树叶到树干NSC平均浓度分别减
少了66.42% (蒙古栎)66.37% (兴安落叶松)
73.89% (红松)
3种树种的NSC含量标准化为树木胸径为
1 三种树种各组织中非结构性碳水化合物及其组分的浓
(平均值±标准误差)。图中ab表示显著性差异组别(
α
=
0.05)
Fig. 1 Concentrations of nonstructural carbohydrate (NSC)
and its components in the tissues of the three tree species (mean
± SE). Larch, Larix gmelinii; Oak, Quercus mongolica; Pine,
Pinus koraiensis. a and b in the figures stand for the significant
difference groups (
α
= 0.05).
2 非结构性碳水化合物及其组分浓度影响因子的方差分析
Table 2 ANOVA of factors influencing concentrations of nonstructural carbohydrate (NSC) and its components
非结构性碳水化合物组分
NSC component
变异来源
Source of variation
自由度
df
F
F-value
概率
p
可溶性糖 Soluble sugar 树种 Species 2 20.7 <0.01
组织 Tissue 3 110.5 <0.01
树种×组织 Species × Tissue 6 8.4 <0.01
淀粉 Starch 树种 Species 2 6.4 <0.01
组织 Tissue 3 29.9 <0.01
树种×组织 Species × Tissue 6 9.1 <0.01
总量 Total 树种 Species 2 16.5 <0.01
组织 Tissue 3 90.0 <0.01
树种×组织 Species × Tissue 6 4.7 <0.01
于丽敏等: 三种温带树种非结构性碳水化合物的分配 1249
doi: 10.3724/SP.J.1258.2011.01245
30 cm后比较发现, NSC的含量随树种、组织而存在
显著差异(2)3种树种的可溶性糖、淀粉和总NSC
含量的大小顺序均为: 兴安落叶松>蒙古栎>红松,
但是不同树种的各个组织中的NSC及其组分含量
呈现出不同的排列顺序(2)
2.2 非结构性碳水化合物的分布格局
NSC在树体内的相对分布格局因树种和NSC
分不同而变异很大(3)蒙古栎的树干和树枝中的
可溶性糖含量各占其总量的1/3, 而兴安落叶松
红松则以树根为主, 分别占总量的47.1%45.9%,
2 三种树种各组织中非结构性碳水化合物及其组分的含
量。三种树种的树木胸径均标准化为30 cm。图中ab表示
显著性差异组别(
α
= 0.05)
Fig. 2 Contents of nonstructural carbohydrate (NSC) and its
components in the tissues of the three tree species. The diame-
ters at breast height of all trees for the three species are nor-
malized to 30 cm. Larch, Larix gmelinii; Oak, Quercus mongo-
lica; Pine, Pinus koraiensis. a and b in the figure stand for the
significant difference groups (
α
= 0.05).
3 三种树种非结构性碳水化合物及其组分在组织中的分
配。
Fig. 3 Allocation of nonstructural carbohydrates (NSC) and
its components within the tissues for the three tree species.
Larch, Larix gmelinii; Oak, Quercus mongolica; Pine, Pinus
koraiensis.
其次是树枝(分别占27.2%29.6%)3种树种淀粉含
量分布的大小顺序均为: 树干>树根>树枝>树叶,
但蒙古栎树根中淀粉的含量(40.2%)显著高于兴安
落叶松和红松根中的含量(25.3%), 而前者树枝中
淀粉的含量(14.1%)却显著低于后者(22.6%)3种树
种树根和树枝中总NSC含量相近, 平均分别占总量
34.9% 24.4%, 但红松树干中总NSC 含量
(28.3%) 显著低于蒙古栎和兴安落叶松(平均为
36.7%)。红松树叶中NSC及其组分的含量均显著高
于其他树种(3)
2.3 非结构性碳水化合物在根系中的分布
3种树种根系中的NSC及其组分的浓度没有统
一的模式(4)。兴安落叶松和红松(除了红松的淀
4 三种树种根系中非结构性水化合物及其组分的浓度
(平均值±标准误差)。图中ab表示显著性差异组别(
α
=
0.05)
Fig. 4 Concentrations of nonstructural carbohydrate (NSC)
and its components in the roots of the three tree species (mean
± SE). a and b in the figures stand for the significant difference
groups (
α
= 0.05). Larch, Larix gmelinii; Oak, Quercus mon-
golica; Pine, Pinus koraiensis.
1250 植物生态学报 Chinese Journal of Plant Ecology 2011, 35 (12): 1245–1255
www.plant-ecology.com
粉之外)的可溶性糖浓度、淀粉浓度和总NSC浓度在
粗根、中根和细根之间均无显著差异。兴安落叶松
树根的可溶性糖、淀粉和总NSC的平均浓度分别为
8.714.9813.69 g·100 g–1 DM; 而红松树根的可溶
性糖、淀粉和总NSC平均浓度分别为5.223.11
8.32 g·100 g–1 DM然而, 蒙古栎的总NSC及其组分
随树根大小变化显著(4), 可溶性糖浓度大小为:
细根(3.19 g·100 g–1 DM) >中根(2.89 g·100 g–1 DM)
>粗根(2.61 g·100 g–1 DM), 而淀粉和总NSC浓度的
趋势则与糖的顺序相反, 浓度大小分别为: 粗根
(6.429.02 g·100 g–1 DM) >中根(5.118.01 g·100
g–1 DM) >细根(2.896.08 g·100 g–1 DM)
3种树种的NSC及其组分的含量在根系内的相
对分配格局较为一致, 均以粗根为最重要的储存组
(5), 其中的可溶性糖、淀粉和总NSC含量平均
分别占根系中总量的88.0%90.6%89.9%
2.4 非结构性碳水化合物在树干中的分布
3种树种树干中的NSC及其组分浓度在树干不
同高度(胸高和树冠中部)差异均不显著(p > 0.05),
但是其树干心材与边材之间的浓度差异却随树种
NSC组分而异(6)3种树种心边材的可溶性糖
浓度虽然差异不显著(p > 0.05), 但均表现为边材浓
度大于心材。然而, 3种树种心边材的淀粉和总NSC
5 三种树种非结构性水化合物及其组分在根系中的分
配。
Fig. 5 Allocation of nonstructural carbohydrate (NSC) and its
components within the roots of the three tree species. Larch,
Larix gmelinii; Oak, Quercus mongolica; Pine, Pinus koraien-
sis.
浓度(除了红松的总NSC之外)差异显著, 其中兴安
落叶松和红松的淀粉和总NSC浓度均为心材高于
边材, 而蒙古栎则呈相反趋势。
树干心边材中的NSC其组分含量的相对分
配格局随树种和组分而异(7)除了兴安落叶松和
红松的可溶性糖含量以边材为主(分别占51.0%
58.1%), 其他树种的NSC及其组分含量均以心材
占优势, 心材的淀粉和NSC含量分别占树干总量的
61.0%–76.9%63.0%–70.8%
6 三种树种边材和心材中非结构性水化合物及其组分的
浓度(平均值±标准误差)图中ab表示显著性差异组别(
α
=
0.05)
Fig. 6 Concentrations of nonstructural carbohydrate (NSC)
and its components in the sapwood and heartwood of the three
tree species (mean ± SE). a and b in the figures stand for the
significant difference groups (
α
= 0.05). Larch, Larix gmelinii;
Oak, Quercus mongolica; Pine, Pinus koraiensis.
于丽敏等: 三种温带树种非结构性碳水化合物的分配 1251
doi: 10.3724/SP.J.1258.2011.01245
7 三种树种非结构性水化合物及其组分在边材和心材的
分配。
Fig. 7 Allocation of nonstructural carbohydrate (NSC) and its
components in the sapwood and heartwood of the three tree
species. Larch, Larix gmelinii; Oak, Quercus mongolica; Pine,
Pinus koraiensis.
3 讨论
3.1 非结构性碳水化合物浓度的差异
3种温带树种各组织的NSC加权浓度处于以往
研究的变化范围内(Gaucher et al., 2005), 但是本研
究没有测定树皮的NSC浓度, 而是用边材的浓度代
替树皮的NSC浓度。因为树皮的NSC浓度通常高于
边材(Tromp, 1983), 因此, 尽管树皮在树木生物量
中占的比例很小, 但本文仍然可能会低估树干的
NSC浓度。3种温带树种的树干和树枝的NSC浓度
(分别为3.00–3.695.47–8.09 g·100 g–1 DM; 1)
Hoch (2003) 报道的温带树种(分别为2.0–6.5
2.0–19.5 g·100 g–1 DM)相符, 但是树叶的NSC浓度
(9.47– 11.50 g·100 g–1 DM)略低于后者(10–17 g·100
g–1 DM)。另 外 , 本研究中的树叶和树枝的NSC浓度
均低于长白山岳桦(Betula ermanii) (分别为12–16
8–11 g·100 g–1 DM) (周永斌等, 2009), 可能是因为
亚高山树木为了在低温、风雪等胁迫环境下维持正
常的生理活动而储存了较多NSC的缘故(Ericsson et
al., 1996; Körner, 2003)
不同树种的NSC浓度(2)和含量(3)差异显
, 可能反映了其生长策略的不同(Mooney &
Hays, 1973)。虽然红松和蒙古栎不同组织中的NSC
组分浓度变化有时不一致(1), 但总体上落叶树种
NSC组分浓度和含量通常高于常绿树(3)。这 可
能是因为落叶树在秋季落叶前积累更多的NSC
, 以便应对冬季的维持呼吸消耗和早春展叶生长
的需要(Kobe, 1997)。其中兴安落叶松组织的NSC
浓度及其组分(1)3种树种中均为最高, 这可能
是该树种能适应高寒恶劣环境而成为北方森林的
优势树种的生理机制之一。周永斌等(2009)也报道
长白山岳桦枝叶中的可溶性糖的比例随海拔升高
而增加, 以抗御低温胁迫。
3种树种各组织中NSC的浓度大小顺序(>>
>树干; 1C)Barbaroux(2003) 的研究结果
(即粗根>>树干)类似。产生这种不同组织之间浓
度差异的主要原因可能与树体内的碳源汇及其强
度有关。叶和根是树木代谢活动最旺盛的组织,
是整株树木的NSC, 而根的维持和生长消耗大量
的碳, 是重要的NSC汇。Lacointe(1993)用碳标记
也发现核桃(Juglans regia)的幼嫩组织比其他组织
优先获得NSC可见, 源和高强度的汇组织, NSC
浓度可能较高, 尤其是NSC中可溶性糖的浓度较高
(1)。然 而 , 3种树种的树叶中NSC浓度差异不显著
(1), 支持生长季中后期常绿和落叶树种树叶中
NSC浓度相似的论点(Hoch et al., 2003)Gaucher
(2005)也报道糖槭(Acer saccharum)和加拿大黄桦
(Betula alleghaniensis)在生长季中期树叶的NSC
度相似, 且月份之间差异不显著。
3种树种的NSC组分浓度随根径的变化格局不
一致, 其中红松和兴安落叶松NSC组分浓度的根径
差异基本不显著, 但蒙古栎根系中可溶性糖的浓度
由粗根中根细根呈现递增趋势, 而淀粉和总
NSC浓度则呈现递减趋势(4)造成这种现象的原
因还不清楚。我们推测这可能与树种的抗旱性及不
同根径根的功能有关。蒙古栎主要分布在阳坡上部
干旱瘠薄的立地上, 是东北温带森林中抗旱性最强
的树种之一; 而细根是树木吸收水分和养分的功能
器官。在NSC组分中, 可溶性糖主要起渗透压调节
作用, 而淀粉则是树体中储存的NSC, 两者因环境
条件的变化会发生相互转化(Salleo et al., 2009)。蒙
古栎通过增加细根中可溶性糖的浓度提高水分吸
收能力, 可能是对干旱立地条件适应的一种生理机
制。
树干是树木NSC的主要储存组织, 尤其是蒙古
1252 植物生态学报 Chinese Journal of Plant Ecology 2011, 35 (12): 1245–1255
www.plant-ecology.com
栎树干NSC的相对含量在3种树种中最高(3),
中可溶性糖绝对含量也最高(2), 且边材NSC组分
浓度显著高于心材(6)这可能与该树种的木材特
性和水分利用策略有关。蒙古栎作为环孔材被子植
, 其导管弦径较大、导管分子长, 特别是早材的
输水效率很高, 但同时对干旱胁迫又很脆弱, 甚至
在每日中午也会因水分供应不足而发生导管空穴
化和栓塞, 使水力导度下降80% 以上(Taneda &
Sperry, 2008)。通过将边材薄壁细胞内的淀粉转化
为可溶性糖(Bucci et al., 2003; Salleo et al., 2009),
可能有效地修复导管的栓塞。
树干中NSC及其组分的纵向和径向变化目前
尚无一致的结论。我们的测定结果表明, 树冠中部
和胸高处树干的NSC及其组分浓度差异不显著,
PiispanenSaranpää (2001)对垂枝桦(Betula pen-
dula)的研究结果一致。然而, Barbaroux(2003)
道无梗花栎(Quercus petraea)和欧洲山毛榉(Fagus
sylvatica)树干的NSC浓度从基部到顶部显著增加。
以往一些研究报道NSC浓度随着生长芯深度的增
加而下降(Magel et al., 1994; Hoch et al., 2003)这从
理论上看似乎合理。这是因为树干的边材含有大量
具有生理活性的薄壁细胞, 行使液流传导、树干支
撑、物质储存等功能; 而心材主要由起机械支撑作
用的死细胞构成(Kozlowshi & Pallardy, 1997)。然
, 我们研究结果显示, 心材和边材的NSC浓度
的差异随树种和NSC组分而变, 表现为心边材的可
溶性糖浓度无显著性差异, 但其淀粉和总NSC浓度
差异显著, 且在针叶树(兴安落叶松和红松)和阔叶
(蒙古栎)中存在相反的格局(6)Newell(2002)
在研究4种热带树种时通常钻取6 cm长的生长芯,
但在偶然钻取的10 cm长的生长芯中却测得大量的
NSCWürth(2005)也发现树干深处含有很高的
NSC浓度, 推测是心材中活跃的射线组织引起的。
3.2 非结构性碳水化合物的分配格局
树木NSC的分配格局受生物因子(如遗传特性、
生长阶段、密度竞争等; Litton et al., 2004; 平晓燕
, 2010)和环境因子(如光照、水分、养分、温度、
CO2浓度等)的综合影响(Rachmilevitch et al., 2006),
与树种在各自生境中的长期生存策略密切相关
(Imaji & Seiwa, 2010a)在同一树种中, 从绝对浓度
, 组织中可溶性糖浓度越高, 其淀粉浓度也越高;
但组织中可溶性糖浓度越高, 其淀粉的相对浓度越
, 两者呈现出显著的互补关系。可溶性糖是树体
中活跃的碳储存物质, 其分配格局反映了树木的生
长状况。蒙古栎可溶性糖含量由树枝树干树根
呈现减少的趋势(3)这表明强阳性树种蒙古栎在
生长盛期主要将碳投资在地上生长, 以便在与周围
植物的光竞争中获得更大的优势(Imaji & Seiwa,
2010b), 从而获得更多的光合产物。相反, 针叶树种
兴安落叶松和红松除了将较大比例的可溶性糖分
配给树枝外, 将更多的可溶性糖投资到根系(1,
3), 这与此时期这两种针叶树种根系生产量显著
大于蒙古栎相符(Quan et al., 2010)。淀粉作为树体
内不活跃的储存物质, 其储存库的大小由组织的浓
度和生物量联合决定, 3种树种均表现为树干>树根
>树枝>树叶。然而, 蒙古栎树根淀粉的含量显著高
于针叶树的含量, 而前者树枝的淀粉含量却显著低
于后者。这与可溶性糖的分布格局正好相反(3)
虽然NSC组分的分配格局在树种之间差异很大,
3种树种的总NSC在树根和树枝中的分配趋于平衡
(3)
粗根中NSC及其组分含量显著高于中根和细
(5), 一方面是因为粗根的生物量远大于中根和
细根, 另一方面是因为粗根的主要功能是储存
(Gaucher et al., 2005)和机械支持作用, 而细根则行
使水分和养分的吸收功能(Gholz & Cropper, 1991)
树干中NSC在心边材之间的分配格局主要是
由其浓度和生物量比例决定的。虽然3个树种的可
溶性糖浓度均表现为边材高于心材, 但蒙古栎的可
溶性糖库却是心材(7)淀粉是树干中广泛而大量
储存的NSC, 在树干中的浓度远高于可溶性糖的浓
, 因而使树干中总NSC随心边材的变化趋势与淀
粉的变化趋势一致, 均以心材占优势(7)
4 结论
3种树种的平均水平看, 兴安落叶松组织的
NSC浓度和含量均为最高; 蒙古栎和红松在不同组
织中的NSC组分浓度变化不同, 但是前者的NSC
其组分的含量显著高于后者。从组织的平均水平看,
叶和根中的NSC及其组分浓度较高; 树干的纵向变
异不显著, 但径向差异因树种和NSC组分而异,
现为心边材的可溶性糖浓度差异不显著, 但其淀粉
和总NSC浓度差异显著; 根系中的根径变异在2
针叶树种中不显著, 而在蒙古栎中显著。
于丽敏等: 三种温带树种非结构性碳水化合物的分配 1253
doi: 10.3724/SP.J.1258.2011.01245
在生长盛期, 蒙古栎将可溶性糖主要投资到地
上生长, 2种针叶树将更多的可溶性糖投资到根
; 淀粉的主要储存库为树干, 在树体内的分布格
局与可溶性糖相反, 从而使总NSC在树根和树枝中
的分配趋于较平衡状态。在树干中, 除了2种针叶树
的可溶性糖库以边材为主外, 心材是淀粉和总NSC
的主要储存库。在树根中, 粗根是NSC及其组分的
优势储存库。3种树种的NSC及其组分的浓度变化
以及分布规律是树木生长过程中各组织的生理功
能和环境因子相互作用的结果, 反映了不同树种的
生长策略和树体内碳源汇强度的变化。
致谢 十二五科技支撑项目(2011BAD37B01)
业公益性行业科研专项(200804001)国家自然科学
基金(30625010)和国家林业局重点项目(2006-77)
同资助。感谢张全智在样地调查中提供的帮助。帽
儿山森林生态站提供了野外基础支持。
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特邀编委: 张守仁 责任编辑:
... We also found that neglecting bark NSC influenced the inter-specific NSC comparison at each sampling time, across sampling periods, and across functional type comparisons. Inter-specific differences in NSC concentrations and distribution in twigs (Barbaroux et al. 2003;Schӓdel et al. 2009), stems (Yu et al. 2011;Zhang et al. 2014), and leaves occur in the same habitat at the same period in temperate tree species due to different growth strategies and ecological adaptations. It is generally believed that the proportion of parenchyma (sum of ray parenchyma and axial parenchyma) in the xylem for broad-leaved tree species is higher than that of coniferous trees, leading to higher NSC concentrations in the former (Kramer and Kozlowski 1979), but this is not always consistent or universal. ...
... In general, twig sugar, starch, and TNC concentrations for the seven tree species measured in our study were comparable to values measured in new branches and slightly higher than those in old/larger branches (≥ 2-year-old branches and diameter ≤ 3 cm) for temperate tree species (Zhang et al. 2013). The range of NSC concentrations measured in twigs in our study was similar to the range of observations measured by the other authors for twigs in other temperate tree species (Hoch et al. 2003;Yu et al. 2011). ...
... The distribution of NSC components in branches varies among species. For example, sugar was the main NSC component in twigs of temperate trees in the middle of the growing season (Barbaroux et al. 2003;Yu et al. 2011;Zhang et al. 2013;Salomón et al. 2016); however, current-year twig NSC of F. sylvatica seedlings (Gansert and Sprick 1998), branch NSC of Q. petraea and F. sylvatica in October (Barbaroux et al. 2003), shoot NSC in Acer rubrum, Q. rubra, and Q. velutina seedlings (Maguire and Kobe 2015), and 1-year-old twig for Q. pyrenaica in April and October (Salomón et al. 2016) were dominated by starch. Critically, these patterns differed significantly when looking at twig NSC concentrations in separate tissues (Barbaroux et al. 2003;Hoch et al. 2003;Schӓdel et al. 2009;Puri et al. 2015). ...
Article
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Key message Bark was the major NSC component in twigs across species. Future research should increasingly follow a bark–xylem approach for a better understanding of NSC distribution and its function in the twig. Abstract Despite extensive research on non-structural carbohydrates (NSC), the distribution of total NSC (TNC) and its primary components (sugar and starch) to the bark and xylem of twigs remains poorly understood. We determined seasonal NSC dynamics in twig bark and xylem in seven temperate tree species exhibiting different xylem anatomies and leaf habits. Seasonal trends in sugar were similar across species with concentrations peaking at least 15 days earlier in the spring for xylem than bark. However, evergreens exhibited maximum bark starch concentrations in early spring, followed by declines throughout the growing season, whereas deciduous species exhibited early spring declines in bark starch, followed by late growing season increases. Evergreens exhibited limited seasonal variation in xylem starch concentrations, whereas deciduous species exhibited variation in xylem starch concentrations that was similar to variation in bark starch. With a few exceptions, concentrations and seasonal amplitudes for sugar, starch, and TNC were generally higher in bark than xylem. Sugar concentrations were generally higher than starch, especially in the bark, which resulted in variability of TNC concentrations in bark or xylem. NSC concentrations varied significantly between xylem and the entire twig when bark was not explicitly considered. Averaged across species, sugar, starch, and TNC content in bark accounted for 66%, 54%, and 61% of total twig content, respectively, even though bark only accounted for 53% of the total twig mass. We recommend quantifying bark sugar and starch separately from xylem when determining twig NSC concentration and content.
... Hence, the study of plant NSC characteristics has become a hot topic reflecting the adaptability to environmental changes (Myers and Kitajima, 2007). Research on plant NSC mainly focuses on the allocation patterns of NSC (Yin et al., 2009;Yu et al., 2011), spatial-temporal distribution characteristics , and response to environmental changes, such as nitrogen and phosphorus addition , drought stress , CO 2 doubling (Dong et al., 2015), and high-temperature stress (Li N. et al. 2014); However, there is limited exploration of rainfall changes (Zheng et al., 2014). Studies have shown that water changes have a significant impact on the content and composition of NSC in plants ; Goodsman et al. (2010) discovered that nitrogen addition led to a decrease in starch content in the roots of Pinus tabulaeformis. ...
... The occurrence of extreme rainfall events (prolonged rainfall duration and heavy rainfall) is caused by global climate change (Diffenbaugh and Giorgi, 2012). Plant biomass is affected by water mainly (Yu et al., 2011). Studies have shown that increasing rainfall promotes the accumulation of plant biomass while prolonging rainfall duration has the opposite effect (Fay et al., 2000;Ansley et al., 2014). ...
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With global climate change and rising temperatures, rainfall will change. The impact of global rainfall changes on ecosystems has prompted people to delve deeper into how changes in rainfall affect plant growth; Plant biomass, nutrient element content, and non-structural carbohydrate content are very sensitive to changes in precipitation. Therefore, understanding the impact of rainfall changes on seedlings is crucial. However, it is currently unclear how the seedlings of Fraxinus malacophylla Hemsl in rocky desertification areas respond to changes in rainfall. In this study, the response of biomass, nutrient accumulation, and NSC content of Fraxinus malacophylla Hemsl seedlings to different rainfall intervals and rainfall during the dry and rainy seasons was studied. Use natural rainfall duration of 5 days (T) and extended rainfall duration of 10 days(T+) as rainfall intervals; average monthly rainfall was used as the control (W), with a corresponding 40% increase in rainfall (W+) and a 40% decrease in rainfall (W-) as rainfall treatments. The research results indicate that the biomass of roots, stems, and leaves, as well as the accumulation of C, N, and P in Fraxinus malacophylla Hemsl seedlings increase with the increase of rainfall, while the soluble sugar and starch content show a pattern of first increasing and then decreasing. The biomass and nutrient accumulation of each organ showed root>leaf>stem. Except for the beginning of the dry season, prolonging the duration of rainfall in other periods inhibits the biomass accumulation of Fraxinus malacophylla Hemsl seedlings, and promotes the accumulation of C, N, and P nutrients and an increase in soluble sugar and starch content. There was a significant positive correlation (P<0.05) between the nutrient contents of C, N, and P in various organs, as well as between soluble sugar and starch content; And N: P>16, plant growth is limited by P element. These results indicate that changes in rainfall can affect the growth and development of Fraxinus malacophylla Hemsl seedlings, increasing rainfall can promote biomass and nutrient accumulation of Fraxinus malacophylla Hemsl seedlings, and prolonging rainfall intervals and reducing rainfall have inhibitory effects on them. The exploration of the adaptation of Fraxinus malacophylla Hemsl seedlings to rainfall patterns has promoted a basic understanding of the impact of rainfall changes on the growth of Fraxinus malacophylla Hemsl. This provides a theoretical basis for understanding how Fraxinus malacophylla Hemsl can grow better under rainfall changes and for future management of Fraxinus malacophylla Hemsl artificial forests in rocky desertification areas.
... Barbaroux et al. (2003) discovered that the NSC concentrations rose with root diameter in Quercus petraea and Fagus sylvatica roots. In addition, Yu et al. (2011) noted that the fine roots of Quercus mongolica had a lower NSC concentration than the medium roots and coarse roots. Our research only partially supported these findings. ...
... According to Barbaroux et al. (2003), the main NSC reservoir with the greatest amount of biomass was thought to be the stem of Quercus petraea and Fagus sylvatica. The leaves of Picea abies and Pinus cembra (Oren et al., 1988;Gruber et al., 2011), as well as the roots of Pinus elliottii (Gholz and Cropper, 1991) and Pinus koraiensis (Yu et al., 2011), were said to have exceptionally big sugar pools, starch pools, and NSC pools, respectively, according to certain researchers. Thus, the growth traits, survival strategy, and cold tolerance of tree species might account for the disparities in NSC pool dispersion. ...
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Despite the importance of non-structural carbohydrates (NSC) for growth and survival in woody plants, we know little about whole-tree NSC storage. Here, Catalpa bungei trees fertilized using different schedules, including water and fertilizer integration, hole application, and no fertilization, were used to measure the spatial variations of sugar, starch, and NSC concentrations in the leaf, branch, stem, bark, and root. By calculating the volume of whole-tree NSC pools and the contribution of distinct organs, we were also able to compare the storage under various fertilization regimes. We found that the spatial distribution patterns of each organ undergoing different fertilization regimes were remarkably similar. Height-related increases in the sugar and NSC concentrations of the leaf and bark were observed. The concentrations of sugar and NSC in the branch did not appear to vary longitudinally or horizontally. The sugar and NSC concentrations in the stem fluctuated with height, first falling and then rising. The coarse root contained larger amounts of NSC components in comparison to fine root. Contrary to no fertilization, fertilization enhanced the distribution ratio of the leaf, branch, and stem NSC pools while decreasing the distribution ratio of the root NSC pool. Particularly, the addition of fertilizer and water significantly increased the biomass of the organs, enhancing the carbon sink of each organ and whole-tree in comparison to other fertilization regimes. Our main goal was to strengthen the empirical groundwork for comprehending the functional significance of NSC allocation and stock variations at the organ-level of C. bungei trees.
... Before testing non-structural carbohydrates, the samples were first dried for half an hour in a 105 • C oven to inactivate enzymes and then dried to a constant weight at 65 • C. Next, the dried samples were then ground by a grinder, passed through a 100-mesh screen, and sealed into a self-sealing bag for testing. Non-structural carbohydrate content (starch and solute sugars) was tested with an improved anthrone colorimetric method (Jan and Roel, 1993;Yu et al., 2011;Song et al., 2016;Li et al., 2022). A dried sample with a weight of 0.100 g was transferred to a 15-ml centrifuge tube with 10 ml distilled water. ...
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Newly sprouted culm (culm_new) of Moso bamboo can complete its height growth within 1 or 2 months without growing any leaf. This explosive growth without enough leaf photosynthesis may rely heavily on external carbon input, such as carbon storage in the rhizomes or culms from the nearby mother culms (culm_mother). However, the existing studies have not explored the role of new photosynthesized carbon by the nearby culm_mother and the corresponding water dynamics. Therefore, this study monitored non-structural carbohydrates in the culm_mother and water transfer between the culm_new and their attached culm_mother in a 3-month experiment. Nine pairs of newly sprouted and attached culm_mother were categorized into three groups with three different treatments, that is, (1) control without any treatment, (2) cutting off rhizomes between the culm_new and culm_mother (Treatment I), and (3) removing all leaves of culm_mother based on the Treatment I (Treatment II). The differences between non-structural carbohydrates of the culm_mother in the control and treatment I were defined as transferred carbohydrates transferred outward from culm_mother. The difference between treatments I and II was defined as newly photosynthesized carbohydrates of the culm_mother. Before the culm_new leafing, there were significant transferred carbohydrates and newly photosynthesized carbohydrates from the culm_mother. In contrast, the carbon transfer became fewer after leafing. At the same time, the sap flow direction in the rhizomes indicated water flows from culm_new to culm_mother during the day and vice versa at night of the culm_new at the pre-leafing stage. These findings may suggest that the explosive growth of the culm_new relies on both previous carbon storage and newly photosynthesized carbohydrates, and the carbon transfer may be coordinated with water transportation between the culms. Further study may pay attention to the potential support from the overall network of the bamboo stand or groves.
... The whole-tree total NSC pool was calculated as the sum of the four organs. To eliminate the effect of individual tree size on comparison of the NSC and its components among different tree species, we used standardized DBH (30 cm) and standardized tree height (18 m) for both tree species to calculate the individual tree biomass (Furze et al., 2019;Yu et al., 2011). Therefore, differences in organ NSC storages truly reflected changes in NSC concentration. ...
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Nonstructural carbohydrates (NSC) are indicators of tree carbon balance and play an important role in regulating plant growth and survival. However, our understanding of the mechanism underlying drought-induced response of NSC reserves remains limited. Here, we conducted a long-term throughfall exclusion (TFE) experiment to investigate the seasonal responses of NSC reserves to manipulative drought in two contrasting tree species (a broadleaved tree Castanopsis hystrix Miq. and a coniferous tree Pinus massoniana Lamb.) of the subtropical China. We found that in the dry season, the two tree species differed in their responses of NSC reserves to TFE at either the whole-tree level or by organs, with significantly depleted total NSC reserves in roots in both species. Under the TFE treatment, there were significant increases in the NSC pools of leaves and branches in C. hystrix, which were accompanied by significant decreases in fine root biomass and radial growth without significant changes in canopy photosynthesis; while P. massoniana exhibited significant increase in fine root biomass without significant changes in radial growth. Our results suggested that under prolonged water limitation, NSC usage for growth in C. hystrix is somewhat impaired, such that the TFE treatment resulted in NSC accumulation in aboveground organs (leaf and branch); whereas P. massoniana is capable of efficiently utilizing NSC reserves to maintain its growth under drought conditions. Our findings revealed divergent NSC allocations under experimental drought between the two contrasting tree species, which are important for better understanding the differential impacts of climate change on varying forest trees and plantation types in subtropical China.
... Since our samples from northern Mongolia were taken during the late growing season in 2017, and both regions suffered drought in 2017, we suggest that enhanced shoot starch (and also NSC because of very low SS in shoots) was a result of drought events, rather than long-term climate regimes. Our result is consistent with Larix gmelinii in continuous forest in a neighbor region (Yu et al., 2011). High NSC in branches was also observed in Panama after extreme drought stress, which was explained as a reserve carbon supply to leaves in the alpine timberline (Hoch and Körner, 2003a). ...
Article
Isolated patchy forests in the arid timberline of Inner Asia are facing increasing risk of forest mortality with increasing drought frequency. The allocation of nonstructural carbohydrates (NSC) helps forests adapt to increasing drought. Previous studies that focused on site-level observations of NSC responses to changes in seasonal rainfall suggested that NSC in branches and stems showed no difference under different levels of drought stress. We conducted large-scale sampling of Larix sibirica-dominated forest patches of different sizes at 7 sites with different mean annual precipitation (MAP) in northern Mongolia in August 2017. Results showed that MAP determines the leaf and stem soluble sugar (SS), leaf and branch starch concentrations of Larix sibirica. The branch stores more starch at lower MAP. A comparison of seasonal NSC dynamics between wetter and dryer sites in the arid timberline of northern China shows that starch in stems is significantly higher for both Pinus sylvestris var. mongolica and Betula platyphylla at drier sites in the dry year 2017 than the normal year 2016. Our two lines of evidence suggest that the enhanced shoot starch allocation is an immediate response of trees to drought, rather than an adaptation strategy to regional climate dryness, although a spatial pattern may exist.
... Studies (Das et al. 2005;Tan et al. 2009) have shown that the flood tolerance of a plant and its later recovery and growth may be highly correlated with the levels of carbohydrate storage in the plant itself. NSCs are important substances that are involved in plant life processes (Pan et al. 2002;Yu et al. 2011). The NSC contents in plants generally reflect the overall supply of carbon to plants; moreover, they represent the growth status of plants, their ability to buffer the effects of external interference and stress, and their adaptation strategies (Wurth et al. 2005;Myers and Kitajima 2007). ...
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This study investigated the physiological and ecological processes of Taxodium distichum in the water-level-fluctuating zone (WLFZ) of the Three Gorges Reservoir (TGR). We determined the contents of non-structural carbohydrates (NSCs), N and P in the aboveground parts and root systems of T. distichum individuals that had experienced 3 yearly flooding cycles. These flooding cycles were driven by the operation of the reservoir in the Zhong County vegetation restoration demonstration area. This flooding inhibited the growth of T. distichum. The plant heights and canopy diameters of the flooded groups were significantly smaller than those of the control group. The flooding facilitated the synthesis of NSCs, and the soluble sugar content in the NSCs increased. The flooding inhibited the uptake of N and P, but the N/P ratios remained stable. The ratios of NSCs to N or P increased. T. distichum adapts well to submergence because of its regulation of NSC synthesis and storage, its balancing of the inputs of photosynthetic products to growth and storage, and its storage of material during exposure to maintain physiological activities during winter submergence and the energy sources required for growth during exposure. This study may provide a useful reference for use in vegetation reconstructions in areas with hydrological characteristics similar to those of the TGR.
... Physiological variables were sampled before and 24 h after no-choice feeding, separately. The soluble sugar concentration was analyzed using the colorimetric method [92] [93]. The total phenolic concentration was determined according to Malinowski et al. [50]. ...
Article
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Alkaloids are usually thought to be responsible for protecting endophyte-infected (EI) grasses from their herbivores. For EI grasses that produce few alkaloids, can endophyte infection enhance their resistance to herbivores? Related studies are limited. In the Inner Mongolian steppe, Achnatherum sibiricum is highly infected by Epichloë endophytes, but produces few alkaloids. Locusts are the common insect herbivores of grasses. In this study, A. sibiricum was used as plant material. Methyl jasmonate (MJ, when applied exogenously, can induce responses similar to herbivore damage) treatment was performed. The effects of endophyte infection and MJ treatment on the resistance of A. sibiricum to Locusta migratoria were studied. We found that locusts preferred EF (endophyte-free) plants to EI plants in both choice and no-choice feeding experiments. Endophyte infection enhanced the resistance of A. sibiricum to locusts. Endophyte infection decreased soluble sugar concentrations, while it increased the total phenolic content and phenylalanine ammonia lyase (PAL) activity, which may contribute to the resistance of A. sibiricum to locusts. There was an interaction effect between MJ treatment and endophyte infection on the growth of the host. MJ treatment was a negative regulator of the plant growth-promoting effects of endophyte infection. There was no interaction effect between MJ treatment and endophyte infection on the defense characteristics of the host. In groups not exposed to locusts, MJ treatment and endophyte infection had a similar effect in decreasing the soluble sugar content, while increasing the total phenolic content and the PAL activity. In groups exposed to locusts, the effect of MJ treatment on the above characteristics disappeared, while the effect of endophyte infection became more obvious. All of these results suggest that even for endophytes producing few alkaloids, they could still increase the resistance of native grasses to insect herbivores. Furthermore, endophyte infection might mediate the defense responses of the host, independent of jasmonic acid (JA) pathways.
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Aims Temperate forest tree species adopt different strategies in storing and utilizing non-structural carbohydrates (NSC). Trunk is the main storage pool of NSC. However, the radial variation and interspecific difference of trunk NSC are still unclear, and how wood porous group—non-porous wood (gymnosperms), diffuse-porous wood and ring-porous wood (both are angiosperms)—influences NSC concentrations of trunks is still uncertain. The objective of this study was to explore the variation of trunk NSC concentrations of major tree species in temperate forests with wood porosity and trunk tissues. Methods We selected 32 tree species in a broadleaved and Pinus koraiensis mixed forest in Muling City, Heilongjiang Province. Bark, sapwood, and heartwood of stem at the breast height were collected to analyze the variation of NSC concentrations with wood porosity and tissue. Important findings (1) Tree species, tissue and wood porosity significantly affected the NSC concentration of trunk. The interspecific variation of concentrations of soluble sugars, starch, total NSC and sugar/starch in the three tissues was large, with the lowest coefficient of variation of 37% (total NSC concentration in bark) and the highest of 101% (starch concentration in heartwood). Tissue, species and their interactions significantly affected trunk NSC concentration. (2) The concentrations of soluble sugar, starch and total NSC decreased with the increasing radial depth. The concentration of soluble sugars and sugar/starch in bark of non-porous species was significantly higher than those of diffuse-porous and ring-porous species. The concentration of starch and total NSC in sapwood was in the order of ring-porous > diffuse-porous > non diffuse-porous wood species. (3) The ratio of soluble sugars, starch and total NSC concentrations in sapwood to in heartwood was about 1 for non-porous wood species, which was significantly lower than those for diffuse-porous and ring-porous wood species, and the correlation of the starch concentration between sapwood and heartwood of non-porous wood was more significant than that of the other two wood-porous types, indicating that the functional differentiation between sapwood and heartwood was clearer for angiosperms than for gymnosperms. These results revealed that wood porosity influenced storage strategy of NSC in trunks of temperate tree species, and it was necessary to distinguish trunk tissues in the study of the whole-tree NSC storage and the ecophysiological function of trees.
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In 3-year-old walnut, a significant part of the starch reserves was converted into soluble sugars in the aerial parts and the fine roots in winter, but at the whole tree level most reserves were used in spring. The reserves stored in autumn were mobilized massively at the very beginning of bud break, and allocated for the most part to respiration. The summer reserves were mobilized to a lesser extent; they were for the most part incorporated in new tissues. The dynamics of reserve mobilization differed among organs. Older (2-year-old) reserves were mobilized to a very slight extent, although they remained available.
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The temperate forest in northeastern China accounts for more than one-third of Chinese forest resources (both area and stocking volume), and plays a key role in the national and global carbon budgets and climatic system. However, few allometric equations exist for accurately estimating biomass and carbon budgets of the forest. In this study, allometric equations were developed relating component biomass to diameter at breast height (DBH) and tree height (H) to DBH for 10 co-occurring tree species in the Chinese temperate mixed forest. The 10 species were Korean pine (Pinus koraiensis Sieb. et Zucc.), Dahurian larch (Larix gmelinii Rupr.), Mongolian oak (Quercus mongolica Fisch.), white birch (Betula platyphylla Suk.), Amur cork-tree (Phellodendron amurense Rupr.), Manchurian walnut (Juglans mandshurica Maxim.), Manchurian ash (Fraxinus mandshurica Rupr.), aspen (Populous davidiana Dode), maple (Acer mono Maxim.), and Amur linden (Tilia amurensis Rupr.). The biomass components included stem, current-year branch, older branch, current-year foliage, older foliage, stump, and coarse root (diameter >= 5 mm). Harvested tree DBH ranged from 2.4 to 57.1 cm. Generalized biomass allometric equations that ignored tree species, based on DBH and fitted on a log-log scale, explained more than 90% of variability in woody component biomass, but the species effect was significant (alpha = 0.05). Including tree height as the second independent variable in the allometric equations improved the accuracy of biomass estimates, especially for foliage biomass. The relative differences in biomass estimated from the generalized, DBH-only, and DBH-H combined equations varied from -50.6% to 43.9% depending upon model form, species, and biomass component. Foliage biomass was more variable than other component biomass both across and within tree species. Some potential sources of error in biomass estimation were also discussed.
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