盾叶薯蓣、黄山药、小花盾叶薯蓣的光合特性比较

 在植株的旺盛生长期分别测定了盾叶薯蓣、黄山药、小花盾叶薯蓣叶片的叶绿素含量和净光合速率,试验结果表明:叶绿素含量以盾叶薯蓣最高,小花盾叶薯蓣和黄山药的含量相近,从同种植物的不同叶位来看,不论是盾叶薯蓣、小花盾叶薯蓣还是黄山药都表现为中部叶片含量最高、基部叶片次之,顶部叶片最低的规律;盾叶薯蓣的净光合速率最高,其次是黄山药,小花盾叶薯蓣最低。同种植物,中部壮叶龄的光合作用强于基部的,顶部嫩叶的光合作用最弱,这与叶绿素含量成正相关;这3种薯蓣的净光合速率日变化进程均呈一条典型的双峰曲线,上下午均有一个峰值,上午的峰值高于下午,在这两个峰值之间形成一个低谷,即薯蓣的光合作用也有“午休”现象。

Comparison on the Photosynthetic Characteristics of Dioscorea zingiberensis,D.panthcica and D.parriflora

Photosynthetic rate and chlorophyll contents of Dioscorea zingiberensis, D.panthaica and D.parriflora were analyzed by using functional leaves. The results indicated: D. zingiberensis was the highest, D. parriflora and D. panthacica were similar in the chlorophyll content. They also followed the regulation that the chlorophyll content is higher in mid-position leaf and the lowest in the top-position leaf; D. zingiberensis was the highest, D. panthacica middle,and D. parriflora the lowest in photosynthetic rate, showing a positive proportion to chlorophyll content; they showed a double-peak curve, i.e., the peak in the morning and higher than in afternoon and a low valley at noon in day change trend of the photosynthetic rate.