International Crops Research Institute for the Semi-Arid Tropics
Abstract
Chickpea is sensitive to chilling temperatures (<10°C),
especially at its reproductive phase leading to floral
abortion. The exact causes of reproductive failures are
not fully understood. In the present study, we assessed the
cold-induced damage to development and functioning of
male and female components by growing an early
flowering chickpea genotype ICCV 96029 under warm
conditions of the glasshouse (control; average maximum
and minimum temperature ≥28/15°C) as well as under
cold conditions of the field (average maximum and
minimum temperature ≤20/10°C during reproductive
phase). Low temperature of the field environment
restricted the vegetative growth and delayed all the
phenological stages in comparison to control plants.
Apart from this, it led to some vegetative aberrations like
chlorosis, necrosis of leaf tips and curling of whole leaf.
The damage to reproductive stage involved abscission of
juvenile buds and flowers and abortion of pods. On the
whole, pollen development at young microspore stage
appeared to be severely affected in stressed conditions
compared to the control conditions. Pollen viability was
suppressed during stressed conditions (60%) compared
to normal plants (95%). Stigma receptivity, in vivo pollen
germination and pollen tube growth were inhibited in the
stressed plants. Fluorescent studies showed that the
stigma either did not show any pollen load or pollen
grains did not germinate on its surface in stressed plants.
Even when the pollen grains germinated, the pollen tubes
rarely grew beyond the proximal region of the style;
mostly the pollen tubes were impaired in their growth and
did not reach the ovules leading to failure in fertilization.
The egg and secondary nucleus in such ovules ultimately
disintegrated without fertilizing and hence no seed
formation occurred