关键词: 二氧化碳, 天气条件, 光合作用, 杂交水稻, FACE(Free Air CO₂ Enrichment)

Abstract: The relationship between seed size and number is an important topic in the research of plant reproduction strategy. The seed number, size, and aborted number in each fruit ofParis polyphylla var.yunnanensiswere investigated in Jingdong (1984 m a.s.l.) and Zhenyuan (1025 m a.s.l.) of Puer, Yunnan Province, to better understand: (1) the effects of altitude on seed size and number and (2) the relationship between the aborted seed number and the seednumber/size. The results showed that there was no significant difference in total seed number per fruit between Jingdong and Zhenyuan (P>0.05). The filled seed number per fruit in Jingdong was significantly higher than that in Zhenyuan (P<0.05), and the aborted number wassignificantly lower than that in Zhenyuan (P<0.01). The seed size in Zhenyuan was slightly though not significantly higher than that in Jingdong (P>0.05). The seed abortion rates were positively correlated with the seed numbers in Zhenyuan (P<0.01), and the similar correlation with the seed size was observed in Jingdong (P<0.05). The negative correlation between seed size and seed number was found at different altitudes, suggesting the existence of seed sizenumber tradeoff inP. polyphylla var.yunnanensis. The regression coefficient between the seed size and number in Zhenyuan was significantly lower than that in Jingdong (P<0.05), implying the sensitivity of the tradeoff between seed size and number ofParis polyphylla var.yunnanensis to the changes of altitude.

Key words: weather condition, hybrid rice, FACE (Free Air CO₂ Enrichment), carbon dioxide (CO₂), photosynthesis