外施GABA对玉米幼苗农艺性状及其光合特性的影响

Effects of Exogenous GABA on Agronomic Traits and Photosynthetic Characteristics of Maize Seedlings

为确定高效促进玉米生长的GABA最佳喷施浓度,本试验以稷秾107号为材料,于五叶一心时实施叶面喷施不同浓度GABA处理,研究其对幼苗农艺性状、地上部干重鲜重及光合特性的影响。结果表明,GABA(30~75 mmol/L)处理后玉米幼苗株高、茎粗、叶宽、地上部鲜重干重均高于对照。GABA(15~75 mmol/L)处理后玉米幼苗的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)呈上升趋势,胞间CO_(2)浓度(Ci)呈下降趋势。60 mmol/L GABA处理玉米幼苗株高、茎粗、叶宽、地上部鲜重干重和Pn、Tr、Gs显著升高(P<0.05),Ci显著降低(P<0.05)。相关性分析表明,玉米幼苗叶片的净光合速率与株高、叶宽,蒸腾速率与株高均呈显著正相关,胞间CO_(2)浓度与地上部干重鲜重、净光合速率、蒸腾速率、气孔导度均呈显著负相关。不同浓度GABA处理玉米幼苗考察指标的综合得分依次为:60 mmol/L>45 mmol/L>30 mmol/L>75 mmol/L>90 mmol/L>15 mmol/L>CK。说明60 mmol/L GABA处理玉米幼苗农艺性状及光合特性考察指标的综合评价值最高,60 mmol/L GABA为最佳叶面喷施浓度。

In order to determine the optimum spraying concentration of GABA,the experiment was conducted with Jinong 107 as material by spraying different concentrations of GABA at five-leaf-one-heart stage,and the changes of agronomic traits and photosynthetic characteristics of maize seedlings were analyzed.The results showed that the plant height,stem diameter,leaf width,fresh and dry masses of aboveground part were higher compared with the control after 30~75 mmol/L GABA treatment.After 15~75 mmol/L GABA treatment,the photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Gs)showed upward trends,while the intercellular carbon dioxide concentration(Ci)showed a downward trend.After 60 mmol/L GABA treatment,the plant height,stem diameter,leaf width,fresh and dry masses of aboveground part,Pn,Tr and Gs of maize seedlings increased significantly(P<0.05),and the Ci reduced significantly(P<0.05).Correlation analysis showed that Pn was significantly positively correlated with plant height and leaf width,Tr was significantly positively correlated with plant height,and Ci was significantly negatively correlated with fresh and dry masses of aboveground part,Pn,Tr and Gs.The comprehensive evaluating score of maize seedlings treated with different concentrations of GABA was sequenced as 60 mmol/L>45 mmol/L>30 mmol/L>75 mmol/L>90 mmol/L>15 mmol/L>CK.It indicated that 60 mmol/L was the optimal spraying concentration of GABA for maize.