对生玉米叶面积分布、蒸腾速率和水分利用率的研究

Studies on Distribution of Leaf Area, Transpiration Rate and Water Use Efficiency in Oppositifolious Maize

研究了６个品种（系）的对生和互生玉米的叶面积分布、蒸腾速率（Ｔ_ｒ）和水分利用率（ＷＵＥ）。 结果表明，对生玉米单株叶数和叶面积比互生玉米分别高出１９２％～２２０％和１３０％～１９０％。两者的不 同叶位与叶面积之间均呈极显著的二次抛物线回归关系，即判断得最大叶面积的叶位数为６。后期（灌 浆期起），对生玉米叶绿素含量高于互生的，差异显著。在睛天，对生和互生玉米的Ｔ_ｒ、气孔导度（Ｇ_ｓ） 以中午前后最高，其日变化与光量子通量密度（ＰＦＤ）、叶温（Ｔ_１）、叶片一大气之间的水蒸气压亏缺 （ＶＰＤ）等因子显著相关，ＰＦＤ对Ｔ_ｒ、Ｇ_ｓ影响较明显。对生玉米Ｔ_ｒ和Ｇ_ｓ低于互生的，两者之间的净光 合速率（Ｐ_ｎ）差异不显著，对生玉米的ＷＵＥ高于互生的，差异显著。表明对生比玉生玉米对干旱条件 的适应性较强。

The results indicated that the leaf number and leaf area in plant of oppositifolious maize had increased by 192 % - 220 % and 130% - 190 %, respectively, as compared to that in plant of alternative, but the mean leaf area of oppositifolious maize was lower than that alternative. As it is seem from results that there was a significant parabolical regression relationship between different leaf position and leaf area in oppositifolious and alternative maize, i. e., according to the model of nonlinear regression, 6 of the leaf position in largest leaf area are estimated. After filling stage, cholorophyll content in oppositifolious maize was higher than in alternative. On clear days the diurnal fluctuation of transpiration rate (Tr) and stomatal conductance (Gs) of oppositifolious and alternative maizes leaves shows a single peak, being highest before and after noon, and related significantly to photon flux density (PFD), leaf temperature (T1) and vapor pressure deficiency (VPD). PFD has a significant effect on Tr, and Gs. The results also indicated that there was no significant difference between oppositifolious and alternative maizes to Pn But Tr and Gs in oppositifolious maize was lower than alternative, and water use efficiency (WUE) was higher than that alternative, (α= 0. 05), indicating that the oppositifolious maize adapted to drought condition better than alternative did.