Seedling Vulnerability to Abiotic Stressors: Recovery and Phenylpropanoids

From germination, young seedlings can experience many abiotic stimuli in the environment. We have characterized how seedlings responding to abiotic signals may be influenced by products of the shikimic acid and phenylpropanoid pathway in young (0 to 6-day-old or to 8 day old), completely dark-grown (etiolated) soybean, rice and other crop seedlings. One commonality for all seedlings is that the timing of stress and the concentrations of particular metbolites is critical to responses to abiotic stimuli, which were studied first in the model organism Arabidopsis in order to better study the genetics of the responses. Thresholds and responses to salt, chilling, heat, and different qualities of UV were studied, and the quantity of phenylalanine in the young seedling is of critical importance. In particular, we examined how the mtr1 mutant of rice responded to particular abiotic conditions and biochemical treatments. Particular developmental indicators in the young seedling of soybean were observed for electron microscopy, biochemical and whole plant phenotypes. Chemical constituents of the young leaves were different, as evaluated by absorbance spectra. For young soybean, stress and/or biochemically manipulated plants were used to evaluate the palatability of leaves to soybean pests in comparison to untreated/non-stressed young soybean.