γ-氨基丁酸对淹水胁迫下不结球白菜生长与光合特性的影响

Effects of γ-aminobutyric acid on the growth and photosynthesis of Pakchoi under waterlogging stress

以不结球白菜品种‘新夏青'为试材,采用双套盆法,研究了淹水胁迫下,叶面喷施不同浓度γ-氨基丁酸(GABA)对不结球白菜生长、光合作用的影响。结果表明:(1)淹水胁迫显著抑制了不结球白菜幼苗生长,使植株的株高、根长、叶面积,鲜重都显著降低,而叶面喷施适宜浓度GABA可有效缓解胁迫对生长的抑制,使各生长指标都显著提高,且40 mmol/L处理时效果最好。(2)淹水胁迫下幼苗叶绿素含量比正常栽培处理组显著下降,但淹水胁迫下喷施适宜浓度GABA可以提高叶绿素a、叶绿素b和叶绿素总量(a+b),其中40 mmol/L时达到最大值,有效缓解淹水胁迫对光合色素的伤害。(3)淹水处理显著降低了不结球白菜幼苗光合作用效率,幼苗Fv/Fm、qP、ETR、产量均显著下降,qN显著升高,破坏了幼苗荧光系统;幼苗净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)均显著降低,胞间CO_2浓度(Ci)显著升高,光合效率显著下降。叶面喷施适宜浓度GABA可以有效缓解淹水胁迫对光合作用的抑制。

＇XinXiaqing＇ was selected as material to study the effects of γ-aminobutyric acid（GABA） on growth and photosynthesis of Pakchio seedlings under waterlogging stress.The results showed that：（1） The waterlogging stress significantly reduced plant growth,plant height,root length,leaf area and fresh weight.Spraying GABA on leaf effectively relieved the stress of waterlogging stress,significantly improved the growth indicators of plant;and the effects of 40 mmol/L was the best.（2） The Chlorophyll content under waterlogging stress reduced more significantly than under normal cultivation,and suitable concentration of GABA could improve the content of Chlorophyll a,Chlorophyll b and Chlorophyll（a ＋ b）.The Chlorophyll content reached the maximum when GABA was 40 mmol/L,which effectively relieved the damage of waterlogging stress on photosynthetic pigment.（3） Waterlogging stress significantly reduced the Fv/Fm,qP,ETR,Yield of seedlings,increased the qN,which destroied the chlorophyll fluorescence system;significantly reduced the Pn、Gs、Tr of seedlings,increased the Ci,significantly reduced photosynthesis efficiency.Spraying appropriate GABA on leaf could effectively alleviate damage to the seedling fluorescence and photosynthesis from waterlogging stress.