Comparison of water flow capacity in leaves among sweet corn genotypes as basis for plant transpiration rate sensitivity to vapor pressure deficit
Jafarikouhini, N., Sinclair, T. R., & Resende, M. F., Jr. (2022, February 15). CROP SCIENCE.
Abstract Genotypes in crop species have been identified that initiate partial stomata closure at elevated atmospheric vapor pressure deficit (VPD), which results in conserved soil water for crop use during subsequent water‐deficit episodes and thereby allowing for possible yield increase. In sweet corn ( Zea mays L), 17 genotypes have been previously identified with the VPD‐responsive trait, although the VPD value at the initiation of stomata closure varied among genotypes. A hypothesis to explain variation in transpiration response to VPD is that water flow capacity in the leaves differs among genotypes. To gauge water flow capacity in leaves, the rate of stomata opening was observed visually after stomata closure was induced by 3 kPa VPD. The stomata opening time was rapid and varied among genotypes from 90 to 179 s. However, there was no correlation between opening time and the VPD at which partial stomata closure was initiated in intact plants. An additional set of experiments was done to examine whether genotypic differences in a subpopulation of silver‐inhibited aquaporins might contribute to differences in leaf water flow. There was a correlation among genotypes between slow opening time of the stomata and greater inhibition of transpiration rate following feeding leaves with silver ion. However, the response to the silver treatment did not correlate with the VPD at which transpiration decrease of intact plants was initiated. These results indicate that the differences observed in the water flow capacity in sweet corn leaves were not major factors accounting for the genotypic differences in whole‐plant transpiration response to elevated VPD.