赤霉素GA4+7种子引发处理对玉米光合作用及产量的影响

研究了外源赤霉素处理玉米种子对其光合特性的影响，可为通过外源激素调控玉米生长和种子加工技术开发提供依据。以玉米种子‘郑单958’为材料，设置10、60、120 mg/L 3个质量浓度的GA4+7m（GA4）:m（GA7）=40:60]进行浸种后回干的引发处理，以常规不处理的种子为对照，测定了大田试验玉米叶片光合参数、叶绿素荧光参数、叶面积及光合产物积累量及光合色素含量。结果表明:GA4+7种子引发处理可提高玉米叶片的净光合速率、气孔导度、胞间CO2浓度、单株叶面积、干物质积累量以及光合色素含量，同时可降低叶绿素a与叶绿素b比值，有效降低初始荧光（F0），增大最大荧光（Fm）、PSⅡ的光能转换效率（Fv/Fm）和实际量子效率（F/Fm'），提高百粒重和籽粒产量，其中以60 mg/L的GA4+7处理（G2）效果最明显。在三叶期、七叶期与拔节期，G2处理玉米的净光合速率分别比对照提高74.3%、42.6%和39.6%（差异显著，P0.05），单株叶面积分别提高30.9%、48.5%和24.1%（差异显著，P0.05），干物质积累量分别增加19.6%、46.9%和52.9%（差异显著，P0.05），总叶绿素含量分别提高21.5%、12.1%和11.1%（差异显著，P0.05），百粒重和籽粒产量显著高于对照，分别提高6.0%和9.7%（P0.05）。

Effect of gibberellin (GA4+7) priming treatment on photosynthesis and yield of maize

In this study, the effect of gibberellin seed soaking on photosynthesis of maize has been studied, which provided a theoretical basis for the application of exogenous hormone on maize growth and seed processing. The seeds of maize (Zhengdan 958) were taken as experimental materials. 10, 60, 120 mg/L gibberellin (GA4+7) solutions were employed to soak and dry the seeds. The parameters of leaf photosynthesis and chlorophyll fluorescence, photosynthetic pigment content, leaf area and photosynthate accumulation were tested in the field. The results showed that priming the seeds with GA4+7 can improve the net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, leaf area per plant, dry matter accumulation and photosynthetic pigment content and reduce the ratio of Chl a and Chl b, which effectively decreased the initial fluorescence (F0) and increased the maximal fluorescence (Fm), photochemical efficiency of PSⅡ(Fv/Fm) and quantum yield (⊿F/Fm'). Thus, it enhanced the hundred kernel weight and grain yield, and the most obvious effect was the sample treated with 60 mg/L GA4+7 (G2) among all these experiments results. In three-leaf stage, seven-leaf stage and jointing stage, compared with the control, the net photosynthetic rate of G2 significantly increased by 74.3%, 42.6% and 39.6% (P 0.05), respectively. The leaf area per plant significantly improved by 30.9%, 48. 5% and 24.1% (P 0.05), respectively. Moreover, dry matter accumulation sharply increased by 19.6%, 46.9% and 52.9% (P 0.05), respectively. The chlorophyll content was raised by 21.5%, 12.1% and 11.1% (P 0.05), respectively. As a result, the hundred kernel weight and the grain yield has increased by 6.0% and 9.7% (P 0.05), respectively.