遮荫胁迫对不同耐阴性玉米叶绿素含量的影响

以易空秆和不易空秆的两个杂交种、易空秆和不易空秆的成对近等基因系为试材,在遮荫胁迫下对光合色素的反应差异进行比较研究。结果表明,不易空秆杂交种和不易空秆近等基因系对遮荫胁迫会产生叶绿素a、叶绿素b和总叶绿素含量升高的反应,并随遮荫强度的增加而增幅加大,易空秆品种(系)则不具备此能力。两个近等基因系的叶绿素a/b值在遮荫胁迫后均产生下降反应,但不易空秆系始终高于易空秆系。说明不易空秆品种(系)的耐阴性机制在于具有较高的叶绿素含量、遮荫胁迫下维持较高叶绿素含量的能力以及对弱光条件的主动适应能力。试验初步探明了区分易空秆和不易空秆杂交种、自交系的遮荫胁迫强度范围以及引起幼穗发育障碍、造成空秆的遮荫胁迫时期。

Effect of Shading Stresses on Chlorophyll Content of Different Shade-Tolerances Maize Varieties

Different responses of chlorophyll content to shading stress were compared by using two hybrids of vulnerable and invulnerable barren stalk and paired near-isogenic lines of vulnerable and invulnerable barren stalk as experimental materials. The results showed as follows: content of chlorophyll a, chlorophyll b and total chlorophyll of hybrid and near-isogenic line of invulnerable barren stalk increased under the shading stress and their increasing extents also increased with the increase of shading stress, which showed their better acclamatory abilities to low light intensity, however, vulnerable barren stalk hybrid and line did not have this ability. It also showed a decrease chlorophyll a/b value of paired near-isogenic line both after shading stress, while the values of invulnerable barren stalk line were always higher than those of vulnerable barren stalk line. Shade-resistant mechanism of invulnerable barren stalk hybrid and line was mainly attributed to their higher contents of chlorophyll, abilities of maintaining higher content of chlorophyll under the shading stress and better initiative acclimation to weak illumination conditions in this case. The experiment also preliminarily explored shading intensity range and shading periods leading to young ear development disabilities and barren stalk to distinguish hybrids and paired near-isogenic lines of vulnerable and invulnerable barren stalk.