冬小麦群体光照条件及其光合特征

Irradiation Condition and its Feature of Photosynthesis in Winter Wheat Population

冬小麦孕穗期冠层对光的截获率最大。由于叶龄的差异,旗叶在展开后的20—30天内,光合速率是以后光合速率的2—3倍。开花后旗叶的光合速率,约近倒4叶的2倍。一天内光合有效时间各叶片不同。孕穗期旗叶为13.5 h/d时,倒2叶为12.5 h/d,倒3叶为11.0 h/d,倒4叶为7.0h/d。 小麦孕穗和灌桨期群体光合速率最高,生育期变化曲线呈双峰型。I—P关系曲线自孕穗期至灌桨期无饱和趋势,在土壤水肥充足的条件下,光合速率变化曲线没有午休现象。

The transmissivity is the lowest, the intercaption is the highest in booting stage of winter wheat. So the problem of irradiation is significant on requirement and offer. The flag leaf's photosynthesis (P)is reduced 2-3 times after spreading 20-30th day to 30-45th day for different leaf age. During anthesis the flag leaf's P is about 2 times as many as 4th leaf from top. The active time for P in the same day is different among leaves. During the booting,it is 13. 5 h/d for flag leaf. 12. 5 h/d for 2nd leaf from top, 11.0 h/d for 3rd leaf from top and 7. 0 h/d for 4th leaf from top. The population P is higher in booting and filling than other stages. The growing and developmental phase appears double peaked curve. I-P response appears non-saturable trend from booting to filling stage. Population P don't show 'Midday Rest' under enough supply of fertilizer and soil water.