Low temperature-induced aberrations in male and female reproductive organ development cause flower abortion in chickpea

Chickpea (Cicer arietinum L.) is susceptible to low temperature (LT) at reproductive stage. LT causes flower abortion and delays pod set in chickpea until terminal drought becomes an issue, thereby decreasing yield potential. In chickpea, flower and anther/pollen development as well as LT-induced abnormalities on anther and pollen development are described inadequately. In the present manuscript, we report flower development stages, anther development stages, and aberrations in male gamete formation in chickpea under LT. Flower length was linearly correlated to flower and anther stages and can be used to predict these stages in chickpea. LT affected male gamete development in a flower/anther age-dependent manner where outcome ranged from no pollen formation to pollen sterility or no anther dehiscence to delayed dehiscence. In anthers, LT inhibited microsporogenesis, microgametogenesis, tapetum degeneration, breakage of septum and stomium, and induced pollen sterility. Whereas disruption of male function was the prime cause of abortion in flowers below vacuolated pollen stage, flower abortion was due to a combination of male and female reproductive functions in flowers with mature pollen. The study will help in elucidating mechanisms governing flower development, anther and pollen development, and tolerance/susceptibility to LT.