硝态氮对去叶多花黑麦草再生性的影响及其调控机制

王 佳，王晓凌,2

(1.河南科技大学农学院，河南 洛阳 471003； 2.中国科学院植物研究所，北京 100093)

在多次牧食去叶的情况下，牧草叶片的持续再生能力体现了其耐牧性。牧草的耐牧性不仅在其抵御外界伤害、维持自身生存和繁衍的过程中起着关键的作用，而且对提高牧草产量和维持畜牧业可持续发展有着重要的意义[1-2]。

在多次去叶的情况下，牧草根系贮存的有机物是其叶片再生的主要物质来源[3-4]。然而，去叶后根系有机物的大量消耗严重影响了根系的生物功能[5-6]，改变了根系细胞分裂素的分泌和运输，从而使叶片细胞分裂素含量降低，叶片生长受阻[7-9]。因此，去叶后牧草根叶间细胞分裂素的运输是影响其叶片持续再生的重要因素。

1 材料与方法

1.1试验材料 试验在河南科技大学温室大棚进行，供试草种为一年生多花黑麦草特高(Tetragold)，种子由北京百绿集团提供。

1.3测量指标及方法 将每一桶剪割下的黑麦草新鲜叶片置于65 ℃的烘箱中烘干60 h后称量，其质量即为每桶黑麦草新生叶片生物量。伤流液的收集采用重量法测定，每次去叶后，在每桶黑麦草的剪割切口处套上装有脱脂棉的已称好质量的小塑料袋,让脱脂棉贴紧切口, 用橡皮筋扎紧袋口，12 h后收袋称量，其质量增加量除以小时数即为每小时每桶黑麦草的根系伤流量。将每次去叶后的叶片和吸附有伤流液的脱脂棉等样品放入-80 ℃冰箱中保存，用来测试激素含量。

2 结果与分析

图1 新生叶生物量和根系伤流量Fig.1 Biomass of newly grown leaves and root bleeding sap quantity

图2 新生叶、根系NO3-含量及伤流液NO3-积累量 content in newly grown leaves and roots, accumulated NO3- quantity in bleeding sap

图3 新生叶吲哚乙酸、赤霉素、脱落酸含量及伤流液吲哚乙酸、赤霉素、脱落酸积累量Fig.3 IAA, GA and ABA content in newly grown leaves, accumulated IAA, GA and ABA quantity in bleeding sap

2.4相关性分析 第2次去叶后新生叶ZR+iPA含量，第3次和第4次去叶后新生叶ZR、iPA及ZR+iPA含量均与新生叶生物量之间存在显著的正相关关系(P<0.05)。但第4次去叶后新生叶IAA、GA及ABA含量与再生叶生物量之间均无显著相关关系(P>0.05)。表明多次去叶下新生叶细胞分裂素是影响黑麦草叶片持续再生相对稳定的关键因素(表1)。

第2次至第4次去叶后新生叶ZR含量与伤流液ZR积累量、新生叶中iPA含量与伤流液iPA积累量以及新生叶ZR+iPA含量与伤流液ZR+iPA积累量之间均不存在显著相关关系(P>0.05)(表2)。说明多次去叶后根系向叶片运输的细胞分裂素对新生叶细胞分裂素含量的贡献可以忽略。

图4 新生叶细胞分裂素含量及伤流液细胞分裂素积累量Fig.4 Cytokinin content in newly grown leaves, accumulated cytokinin quantity in bleeding sap

表1 不同去叶次数新生叶各激素含量与新生叶生物量之间的相关性分析Table 1 Correlation analysis between hormone content and biomass of newly grown leaves in all treatments

表2 各激素新生叶含量与其伤流液积累量之间的相关性分析Table 2 Correlation analysis between hormone content in newly grown leaves and accumulated hormone quantity in bleeding sap in all treatments

表3 所有处理新生叶生物量、新生叶含量、伤流液积累量及根系含量之间的相关性分析Table 3 Correlation analysis among newly grown leaf biomass, content in newly grown leaves, accumulated quantity in bleeding sap and content in roots in all treatments

表4 所有处理新生叶中含量与各激素含量之间相关性分析Table 4 Correlation analysis between and hormone content in newly grown leaves in all treatments

3 讨论

4 结论

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