杂草稻苗期强竞争性的生理机制

为揭示杂草稻比栽培稻苗期生长迅速的机制,随机选择均匀分布于江苏省6个市的杂草稻样品和典型粳稻品种日本晴(Nipponbare),比较了其连续7 d的种子萌发率以及在14、21、28、35 d的幼苗株高变化和光合作用原初反应指标之间的差异。结果表明,江苏省6个市的杂草稻样品均比栽培稻提早2 d萌发,且均未表现出休眠性。杂草稻苗期株高在第35天时,均显著高于栽培稻。在播种后14、21、28和35 d,杂草稻光合作用原初反应的7个指标均高于栽培稻,说明杂草稻苗期具有强光合性能。研究表明,江苏省杂草稻比栽培稻早2 d萌发,至少播种后14 d苗期光合效能开始高于栽培稻,播种后28 d左右株高开始显著高于栽培稻。

Physiological mechanisms of strong competition of weedy rice at seedling stage

The differences between weedy rice and rice cultivar in seed germination, seedling height, and primary reaction of photosynthesis were compared, and the mechanisms of rapid growth ability of weedy rice were studied. Samples of weedy rice were randomly selected from six evenly distributed cities in Jiangsu Province with a typical japonica rice cultivar Nipponbare as the control. Seed germination rate was recorded consecutively for seven days. Seedling height and primary reaction parameters of photosynthesis were recorded after 14, 21, 28, 35 days, respectively. The results showed that weedy rice from six selected cities all germinated two days earlier than rice cultivar. No weedy rice showed dormancy trait in Jiangsu. All weedy rice seedlings are taller than rice cultivar 35 days after sowing (DAS). Seven primary reaction parameters of photosynthesis in weedy rice were all higher than those of rice, suggesting the higher photosynthesis ability in weedy rice. The weedy rice in Jiangsu germinated two days earlier than rice cultivar, and had higher photosynthesis ability by 14 DAS, which might lead to significantly taller seedling height 28 DAS.