Water Deficit and Recovery-Induced Changes in Growth, Photosynthetic Characteristics, Antioxidant Enzymes and Yield of Two Tartary Buckwheat Genotypes

Tartary buckwheat (Fagopyrum tataricum) is an important food crop that is widely adaptable to hostile environments. In this study the responses of two Tartary buckwheat genotypes: drought-susceptible Chuanqiao No. 1 (CQ) and drought-tolerant Jingqiao No. 2 (JQ) in terms of morphology, photosynthesis, physiology and yield to a progressive water deficit and recovery treatment (WD-R) were evaluated. Plants in the well-watered (WW) treatment were watered throughout the experiment. Compared to the WW treatment, water deficit in the WD-R treatment caused decreases in plant height, stem diameter, branch number, stem node number, biomass, seed number, soil water content (SWC), leaf relative water content (RWC), net photosynthesis rate (Pn), intercellular CO2 concentration, stomatal conductance (Gs), transpiration rate (Tr) and Fv/Fm in both CQ and JQ plants. Leaf wilting, malondialdehyde content, superoxide dismutase activity, peroxidase activity, initial fluorescence (F0) and root-to-shoot ratio were significantly increased under water stress in the WD-R treatment. Under the WD-R treatment, compared to CQ, JQ maintained higher RWC, SWC, Pn, Gs, WUE, Fv/Fm, plant height, branch number, stem node number, root biomass, stem biomass, leaf biomass, total biomass, root-to-shoot ratio, seed number per plant, and yield, but a lower Tr and F0. By correlation analysis, Gs was positively correlated with leaf RWC and SWC. These differential growth indexes, biochemical traits and physiological responses might be useful for understanding drought-tolerance genotypes that can grow under water-deficit conditions with minimum yield loss. © 2021 Friends Science Publishers