RNA extracted from leaves of these seedlings was used in RNA seq analysis to study gene expression patterns under well watered and water stressed conditions. The main objectives of this study are to identify genes differ entially expressed under control and stress conditions, to identify allelic variants from these genes and to study the evolutionary signatures of selection. Results Effect of water stress on physiological traits Effect of water stress on several physiological and growth traits was analysed by comparing well watered and water stressed plants. Two way ANOVA revealed significant differences between control and stress treat ments for all the physiological and biomass traits except for root to shoot ratios. While the treatment effect was significant, the population effect was not sig nificant for any of the traits.
Similarly no significant interaction between the treatment and population was observed for any of the traits. Pair Inhibitors,Modulators,Libraries wise comparisons between the populations for traits were also not signifi cant. Water stress significantly affects Leaf water Inhibitors,Modulators,Libraries relations and stomatal conductance Leaf water relations were measured on samples collected 30 days and 52 days after the imposition of stress treatment. Between the two sam pling periods, measurements of water relations were very similar in control seedlings. How ever, in stressed seedlings highly significant differences were Cilengitide observed for these traits between the two sampling periods. Within a treatment at both sampling periods, no significant differences were observed between the populations for any of the water relation traits measured.
The dif ferences between control Inhibitors,Modulators,Libraries and stressed seedlings were much more pronounced 52 days after the imposition of the stress treatment. After 30 days pre dawn water potentials had decreased to Inhibitors,Modulators,Libraries ?0. 67 MPa in stressed seedlings compared to ?0. 47 MPa in controls. By 52 days pre dawn water potentials had fallen to ?2. 89 MPa and negative tur gor pressures were observed in stressed seedlings while in controls these traits were similar to those in sampling 1. Mean stomatal conductance was higher in control seedlings than in water stressed seedlings. Re duction in the stomatal conductance of the Katherine population is higher compared to the other two popula tions, however, as with water relations, the stomatal conductance of the three populations were not significantly different.
Water stress significantly reduces biomass production under stress treatment Water stress had a significant effect on all traits related to biomass production. There was a significant decrease in the amount of water transpired and conse quently there was a significant reduction in total dry mass produced by stressed seedlings. The amount of transpiration fell from 49. 5 kg to 14. 0 kg under stress treatment and total biomass produced fell from 112. 2 g to 28. 7 g under stress treatment. Similarly transpiration efficiency decreased from 2. 24 g kg in control seedlings to 2.