Effects of temperature on pollen viability and in vivo pollen tube growth in Citrus sinensis

Abstract

Temperature is the major factor in global warming and strongly influences the success of plant sexual reproduction. Therefore, there is
an urgent need to assess the vulnerability of species for breeding and planning effective actions. In this study, effects of different tempera-
tures and storage duration on pollen viability and in vivo pollen tube growth were analysed in Citrus sinensis ‘Kozan yerlisi’. The pollens
were obtained before anthesis and stored at 10 °C, 20 °C and 30 °C for 1, 2 or 3 days before analysis.
The pollen viability decreased with increasing temperatures and storage duration from 61.3% to 5.8%. In vivo pollen germination results showed that for one day storage, the pollen growth rates were similar to the control treatment while storing pollens two or three days differed from the control. Pollen germination after storage at 10 °C was lower and not efficient, while after storage at 30 °C no pollen tube germination at all was seen on the stigma. At the same time, storing pollen in low temperature caused delay in pollen tube germination and pollen tube growth, suggesting that pollen that are stored in low temperatures pass into a dormancy process for three to five days.
In conclusion, this study indicated that pollen storage in 30 °C for a long time causes loss of pollination ability while storage in 10 °C
causes dormancy in pollen.