| Two sweet sorghum cultivars, mid-early maturity cultivar “Xingaoliang 3” and mid-late maturity cultivar “Xingaoliang 9”, were planted in saline-alkaline soil. Photosynthetic characteristics and agronomic traits of them were studied. The result showed that: (1) Compared to control, net
photosynthetic rate(Pn), transpiration rate(Tr), stomatal conductance(Gs), intercellular CO2 concentration(Ci), water use efficiency(WUE), and SPAD value(SPAD) were significantly lower in saline-alkaline soil, especially at late growth period. Pn, Gs, WUE, and SPAD of Xingaoliang 3 were higher whereas Tr and Ci were lower than those of Xingaoliang 9 in saline-alkaline soil. (2) The growth durati
on of “Xingaoliang 3” was shortened by 9 days, while “Xingaoliang 9” only survived until jointing stage in saline-alkaline soil. Compared to control, the biomass of two sweet sorghums in saline-alkaline soil was reduced by 57.8% and 76.5%, respectively, and sugar brix by 38.5% and 100%. (3) The correlation analysis indicated that Pn was highly correlated with Gs, PAR, and Ta. At early stage, the reduction in Pn was associated with stomatal limitation, whereas non-stomatal factor was the main cause after heading. |