Chinese Journal of Agrometeorology ›› 2019, Vol. 40 ›› Issue (03): 180-185.doi: 10.3969/j.issn.1000-6362.2019.03.005

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Effect of Increasing Night Temperature on Floret Opening and Grain Setting of Rice

ZHANG Wen-qian, WANG Ya-liang, ZHU De-feng, CHEN Hui-zhe, XIANG Jing, ZHANG Yi-kai, ZHANG Yu-ping   

  1. State Key Laboratory of Rice Biology/Rice Research Institute of China, Hangzhou 310006, China
  • Received:2018-09-13 Online:2019-03-20 Published:2019-03-16

Abstract: Taking indica rice varieties HHZ and HSZ as potting experimental materials, three day/night temperature treatments, namely 36℃/25℃ (T1), 36 ℃/29℃ (T2) and 36℃/33℃ (T3), were set up in artificial climate chamber, which means the daily maximum increasing temperature by 4℃ and the increasing temperature at night by 4℃ and 8℃, respectively, and 32℃/25℃ as CK. Continuous processing for 7 days from the day of heading and flowering, the flowering number, pollen vigor and anther dehiscence rate were observed hourly from 9:00 am to 11:00 am. After treatment, they were moved to the outside and were observed the fruiting rate after ripening. The results showed that, under the condition of increasing daily temperature, the increase night temperature at flowering stage put forward one hour in the flowering peak both for two varieties. Meanwhile, the increase night temperature at flowering stage caused the vitality of pollen, when night temperature increased by 4℃ (T2) and 8℃ (T3), the HHZ vitality of pollen dropped by 13.6 and 17.6 percentage point, HSZ dropped by 1.1 and 4.5 percentage point, which means the pollen vigor of HHZ was more sensitive to the increase night temperature than HSZ. Under the same conditions, the anther cracking rate of rice decreased significantly with the increasing night temperature at flowering stage (P < 0.05), the longer treatment, the greater the effect. The average rate of anther cracking was 73.2% in HHZ and 79.0% in HSZ with treatment T3. The increasing night temperature also caused the decreasing rice seed setting rate, both HHZ and HSZ showed the same tendency, but HHZ was more sensitive to the increasing night temperature than HSZ. The decreasing seed setting rate was mainly due to the decreasing anther dehiscence rate and pollen vigor.

Key words: Rice, Flowering stage, Night temperature, Seed setting rate, Floral organ