Comparison of Photosynthetic Pigment Content in Leaves of Different Positions at Late Growth Stage of Wheat

Photosynthetic pigment contents of four wheat(Triticum aestivum L.) cultivars,Zhengmai 7698,Zhoumai 18,Aikang 58 and Jing 411,were determined by the method of spectrophotometric determination.The results showed that the contents of chlorophyll a,chlorophyll b,total chlorophyll and carotenoid of the four wheat cultivars were top first leafsecond leafthird leaf at heading stage and mid grain filling stage.At heading stage,the average content of chlorophyll a of the four cultivars in first leaf,second leaf and third leaf was 3.22,2.68 and 2.34 mg/g respectively,the average content of chlorophyll b was 1.02,0.89 and 0.82 mg/g respectively,and the average content of carotenoid was 0.59,0.49 and 0.43 mg/g respectively.At mid grain filling stage,the average contents of chlorophyll a,chlorophyll b and carotenoid in first leaf,second leaf and third leafs of the four cultivars were 3.22,2.68 and 1.86 mg/g;1.29,1.15 and 0.81 mg/g;0.14,0.08 and 0.05 mg/g,respectively.The photosynthetic pigment contents had no obvious difference among different cultivars.At mature stage,no obvious regular pattern was found in the photosynthetic pigment contents between different leaves,but great difference existed in different cultivars.The variation law of the chlorophyll a/b was similar to photosynthetic pigment content,and it increased with the increase of leaf position at heading stage and mid filling stage.While at mature stage,the chlorophyll a/b decreased obviously and was higher in third leaf than in first leaf,and maintained stable at the same leaf position between different cultivars.