Paul Greer

Texas A&M University | TAMU · Department of Horticultural Sciences

Globally, a small number of plants have adapted to terrestrial outcroppings of serpentine geology, which are characterized by soils with low levels of essential mineral nutrients (N, P, K, Ca, Mo) and toxic levels of heavy metals (Ni, Cr, Co). Paradoxically, many of these plants are restricted to this harsh environment. Caulanthusampexlicaulis var....

This review discusses our research at Texas A&M University, demonstrating that the accumulative hours of low temperature of the fall and winter of the Chihuahuan Desert stimulates rubber biosynthesis in the indigenous rubber plant, Parthenium argentatum Gray (guayule), by inducing the activities of new enzymes and forming undifferentiated cortical...

Studies have indicated the presence of both a de novo biosynthesis of new polyisoprene chains and the elongation of pre-existing rubber-PP chains in rubber particles from Ficus elastica Roxb. and small rubber particles from Hevea brasiliensis (Willd. ex A. Juss.) Müll. Arg. In this paper, we have isolated rubber particles from the cortical parenchy...

The low temperatures of the Chihuahuan Desert stimulate rubber biosynthesis in guayule plants, primarily by promoting rubber-producing cortical parenchyma cells and inducing the activity of enzymes in the pathway of rubber biosynthesis. Further progress in increasing rubber production in guayule requires a better understanding of the ultrastructure...

Exposure of guayule plants to low temperature promotes the development of rubber-producing undifferentiated cortical parenchyma.Electron photomicrographs of cross-sections 1 cm below the stem tip of guayule plants grown at 27–32 °C days and 7 °C nights with a 16 h photoperiod for 6 months showed cortical parenchyma containing micro-vacuoles appress...

In this paper we have examined rubber particle formation in cortical parenchyma cells of guayule (Parthenium argentatum Gray) plants exposed to the low temperature of the fall and winter of the Chihuahuan Desert that stimulates rubber formation.Plants were transplanted to field plots in May in Ft. Stockton, TX. In September most of the cortical par...

Guayule (Parthenium argentatum Gray) is a rubber plant indigenous to the Chihuahuan Desert of Northern Mexico and Southwestern Texas. In this review we report the nature of the physiological, cellular and biochemical responses of these plants to the low temperature of the desert in the biosynthesis of rubber.Studies on rubber formation in guayule i...