刈割—追氮对小黑麦抽穗后光合特性的影响

Effects of Mowing and Topdressing of Nitrogenon Photosynthetic Characteristics in Triticale

对刈割-追氮处理的小黑麦(中饲237)抽穗后的光合指标及其相互关系进行研究。结果表明,抽穗后旗叶叶绿素总量Chl(a+b)变化为单峰曲线,施肥处理叶绿素含量大于未施肥的处理。叶绿素a和叶绿素b的比值Chl(a/b)变化不大。各处理抽穗后旗叶净光合速率(Pn)高峰出现的时间均在抽穗后18d左右,抽穗后Pn值保持较高水平的时间较长,但下降速度存在差异。除不刈割返青期追氮(处理Ⅱ)、返青期刈割后追氮(处理Ⅲ)两个处理外各处理单茎旗叶同化速率(FLAR)的变化与Pn的变化基本保持一致。处理Ⅱ在Pn方面占优势,但其FLAR小,单株旗叶同化的养分少。旗叶叶面积与Pn呈极显著负相关,Chl(a+b)与Pn之间的相关系数达显著水平。

The photosynthetic physiological indexes after heading and their relationships under different mowed and fertilized N treatments in Triticale (Zhongsi237) were studied. The results showed that the curve of Chlorophyll (a+b) within the flag leaves after heading under different treatments displayed only one peak, and content of Chlorophyll (a+b) under N treatment was higher than that of unfertilized ones. The peaks of net photosynthetic rate (P_n) under different treatments after heading appeared in almost the 18th day after heading, and P_n remained high for quite a long time, but their descending speed showed difference. The changes of FLAR under different treatments were the same as those of P_n, except treatmentⅡ,Ⅲ. Although treatment Ⅱhad advantages in P_n, the FLAR were low, and its flag leaves of single plant assimilated less nutrient substances. There was negative correlation at extremely significant level between P_n and FLA, and a positive correlation at significant level between Chlorophyll (a+b) and P_n.