孕穗开花期持续低温对不同熟期水稻气孔导度的影响

分别以9023、9035、9036为早熟、中熟、晚熟水稻的代表品种,应用人工气候箱在孕穗开花期进行低温处理,旨在分析沈阳地区孕穗开花期不同强度低温对不同熟期水稻叶片气孔导度的影响。低温设置以前一天相同时刻的温度值为基准,设比外界温度低3℃(D3)和低5℃(D5)两个处理水平,持续处理5d,以自然条件下生长的水稻为对照(CK),利用LI-6400光合测定仪测定水稻倒2叶的CO_2响应曲线和光响应曲线。结果表明:(1)CO_2响应过程中,与CK相比,D3和D5的持续低温处理皆可导致9035和9036的气孔导度显著降低,而9023(早熟)仅D5的持续低温导致其气孔导度降低;(2)光响应过程中,与CK相比,D3和D5的持续低温处理使9035(中熟)和9036(晚熟)气孔导度降低,且降低幅度随低温强度的增强而增大,但持续低温处理显著增加了9023(早熟)的气孔导度(P0.01);(3)气孔限制是引起9035(中熟)遭遇低温后光合速率下降的主要原因,而9023(早熟)和9036(晚熟)光合速率的变化主要由非气孔限制导致。说明中熟(9035)和晚熟(9036)水稻品种对低温处理响应较敏感,而早熟(9023)品种对低温不敏感。

Effects of Consecutive Low Temperature on Stomatal Conductance of Rice with Different Maturity Periods at Booting and Blooming Stages in Shenyang Region

The experiment was conducted in climate chamber to explore the effects of different intensities of low temperature on stomatal conductance of rice with different maturity at booting and blooming stages in Shenyang region. 9023, 9035, 9036 were chosen as representative early, middle and late maturity varieties, respectively. Two temperature treatments were stetted for 5 days, which were 3℃(D3) and 5℃(D5) lower than outside temperature of the last day, CO2 and light response curves of second leaf from top were measured for treatment and control plants (grown under natural conditions as control, mark CK) by using LI-6400 photosynthesis analyzer. The results showed that:(1) during CO2 response, the leaf stomatal conductance of D3 and D5 treatment plants showed a significant decrease compared with that of CK plants for 9035(middle) and 9036(late) maturity varieties, while decrease for 9023(early) maturity variety only in D5 treatment. (2) During light response, the leaf stomatal conductance of treatment plants showed the similar variation with the results of (1) compared with that of CK plants for 9035(middle) and 9036(late) varieties, but increase for 9023(early) maturity variety in D3 and D5 treatment(P<0.01).(3) Stomatal limitation mechanism is the main mechanism that leads to decrease of photosynthetic induced by low temperature for 9035(middle) variety, whereas, the decline in photosynthetic rate is mainly due to non-stomatal limitation for 9023(early) and 9036(late) maturity varieties. 9035(middle) and 9036(late) varieties are more sensitive than 9023(early) maturity variety to low temperature.