DIFFERENT WATER MANAGEMENT STRATEGIES OF TWO Sorghum bicolor PARENTAL LINES EXPOSED TO SALT STRESS

MOIRA SUTKA; VICTORIA A VITALI; . KARINA ALLEVA, MOIRA SUTKA, RICARDO DORR, MARIO PARISI Y GABRIELA AMODEO.

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Sorghum [Sorghum bicolor (L.) Moench.] is known as a tolerant crop with capacity to grow and sustain high yields in unfavorable environmental conditions. Dissecting the physiological traits involved in its water adjustment capacity in early developmental stages could improve our understanding in water use efficiency. In previous work, we characterized the differential response to water deficit of two parental lines from Argentina (RedLandB2 and IS9530; Sutka et al., 2016). Here we extend our study to salt stress to analyze the water adjustment capacity of these two genotypes at the whole plant level. Plants were grown in hydroponic conditions for 7 days and then submitted to NaCl (0 up to 300 mM) for 4 hours. Al the leaf level, relative water content is only affected in IS9530 being statistically different at the maximum salt concentration. Interestingly, the osmotic potential component of leaf water status showed a strong robustness, no differences were observed between genotypes along treatment. In contrast, leaf water potential values differ between genotypes (-0.16±0.016 and -0.28±0.031 MPa for RedLandB2 and IS9530 respectively). Stomatal conductance was coupled to root hydraulic behavior in RedLandB2 where remained invariant along treatments. In IS9530, the profile showed a decreased to 50% of the control value.At the root level, hydraulic conductivity (Lpr) maintains in RedLandB2 independently of the salt treatment while IS9530 showed a different oscillatory pattern, decreased its Lpr at 200 mM NaCl but recovered the control value at 300 mM NaCl (14.4±2.8 versus 57.8±7.1 mL g-1 h-1 Mpa-1).In the absence of a transpiration force, root exudate fluxes showed similar reduction in both genotypes but only IS9530 showed a reduced osmolarity difference between the medium and the exudate. In conclusion, all water parameters traits showed that these two lines of sorghum are able to cope with salt stress using different strategies to adjust water management.