Different strategies of seedlings of two Sorghum bicolor lines to deal with drought stress

MOIRA SUTKA; VICTORIA VITALI; GABRIELA AMODEO; MILENA MANZUR

Montpellier

Conferencia; Recent programs in drougth tolerance, from genetics to modelling; 2015

Sorghum [Sorghum bicolor (L.) Moench.] is an ancient drought tolerant crop with potential to replace other cereals not capable to sustain high yields in low or erratic precipitation conditions, a feature on the rise due to climate changes. Understanding the performance of this species in early phenological stages could be a useful tool for future yield improvement programs. The aim of this work was to study the response of sorghum seedlings under drought conditions in two genotypes employed as parental lines in our country: RedLandB2 and IS9530. We characterized morphological, anatomical and physiological parameters at the whole plant level under control and drought conditions in order to perform an integrated study. We found that both lines developed different physiological strategies when were exposed to water restriction. Although both lines were able to change biomass allocation to roots under drought, they showed different root architecture between them. Interestingly, both sorghum lines were able to adjust their plant resistances to water loss at different level: RedLandB2 regulates stomatal resistance (isohydric strategy), while IS9530 controls root resistance (anisohydric strategy). The latter genotype differentially adjusts root hydraulic conductance, where the cellular pathway could be more relevant in such process, involving water channel activity. Moreover, only in IS9530 root hydraulic conductance was restricted in the presence of HgCl2, in agreement with aquaporins activity. This performed approach adds new information for sorghum species that can be used to evaluate phenotypic plasticity for changing environments. Our result provides also new insight in terms of anisohydric and isohydric strategies that can be developed by plants in relation to water management. However, it is still necessary a thorough study to address the physiological/molecular mechanisms triggered in response to drought, including in this scenario the role of aquaporins.