外源6-BA对不同生育时期淹水花生根系生长和荚果产量的影响

【目的】土柱栽培条件下,研究外源细胞分裂素(6-BA)对花生不同生育时期淹水胁迫下根系呼吸酶活性、内源激素含量及荚果产量的影响,为提高淹水胁迫下花生抗性及采用外源激素调控花生生长提供理论依据。【方法】选用山花108为试验材料,以全生育时期正常水分管理(CK)为对照,设置苗期(V3)、花针期(R3)、结荚期(R5)、饱果期(R7)4个淹水时期,于淹水10 d后喷施15 mg·L^-1的6-苄基腺嘌呤(6-BA),共9个喷施组合处理,即全生育时期正常水分管理(CK)、苗期淹水(V3-W)、苗期淹水后喷施外源细胞分裂素(V3-S)、花针期淹水(R3-W)、花针期淹水后喷施外源细胞分裂素(R3-S)、结荚期淹水(R5-W)、结荚淹水后喷施外源细胞分裂素(R5-S)、饱果期淹水(R7-W)、饱果期淹水后喷施外源细胞分裂素(R7-S)。处理后每隔5 d,取样测定根系无氧呼吸酶、有氧呼吸酶活性,内源激素含量,根系干重及根长密度等指标。【结果】淹水显著降低了20—60 cm土层的根系干重及根长密度。淹水结束后,V3-W处理20—40 cm土层无根系。2018与2019生长季,R3-...

Effects of Exogenous 6-BA on Root Growth and Pod Yield of Flooded Peanut at Different Growth Stages

【Objective】The objective of this study was to investigate the effects of flooding stress and spraying exogenous cytokinin on root respiratory enzymes activities, endogenous hormone content and pod yield at different peanut growth stages, so as to provide a theory base for improving peanut resistance to flooding and using exogenous cytokinin hormone to regulate peanut growth. 【Method】Peanut (Shanhua108) was grown in the pot culture experiments with flooding treatment during 10 days at the seedling stage (V3), the flower needle stage (R3), the pod setting stage (R5), and the full fruit stage (R7),respectively. And the normal water management during the whole growth period (CK) was used as the control. Exogenous 6-benzyladenine (6-BA) (15 mg·L^-1) were sprayed to the whole plants at a rate of 250 mL·m^-2 after waterlogging. A total of 9 spraying combinations, namely, normal water management during the whole growth period (CK), flooding at the seedling stage (V3-W), spraying 6-BA after flooding at the seedling stage (V3-S), and flooding at the flower needle stage (R3-W), spraying 6-BA after flooding at the flower needle stage (R3-S), flooding at the pod setting stage (R5-W), spraying 6-BA after flooding at the pod setting stage(R5-S), flooding at full fruit stage (R7-W), spraying 6-BA after flooding at full fruit stage (R7-S). And then the anaerobic respiratory enzymes, aerobic respiratory enzymes activity, endogenous hormone contents, root dry weight (RDW), and root length density (RLD) were determined every 5 days after treatment. 【Result】The RDW and RLD in 20-60 cm soil layers were significantly decreased by waterlogging treatment. There was no root system in 20-40 cm soil layer under V3-W treatment after waterlogging. Compared with the R3-W treatment, the values of RDW and RLD of the 20-60 cm soil layer under the R3-S treatment was increased by 5.15% and 8.59% in the growing seasons of 2018 and 2019, respectively. Flooding stress increased the activities of Alcohol dehydrogenase (ADH), Lactate dehydrogenase (LDH), and decreased the activity of Malate dehydrogenase (MDH). For example, the activity of ADH and LDH was increased under V3-W treatment by 12.49 and 18.99 times, respectively. Whereas, the activity of MDH decreased by 65.15%. In addition, compared with CK treatment, ABA content in the two growing seasons was increased by 22.51%, 15.81%, 10.57% and 5.64% under V3-W, R3-W, R5-W and R7-W, respectively. However, spraying 6-BA significantly reduced the ABA content during R3 stage, which was 7.60% lower than that of R3-W treatment. On the contrary, endogenous ZR content was reduced by flooding stress at all the growth stages. Compared to CK treatment, ZR content under V3-W, R3-W, R5-W and R7-W treatment was decreased by 16.84%, 15.61%, 15.35%, and 8.51%, respectively. While application of exogenous 6-BA decreased the ABA content, but increased the ZR content. Flooding significantly reduced the number of fruit per plant and the yield per plant in the R5 period, which decreased by 38.39% and 30.43% in 2018, respectively, and decreased by 31.60% and 25.06% in 2019. The R3 period was sprayed with 6-BA in the growth season of 2018 and 2019, increased production by 5.38% and 6.91%, respectively. 【Conclusion】 Application of exogenous 6-BA after flooding increased peanut yield due to increasing root respiration performance and the leaf photosynthetic productivity resulting from reducing the root ABA content and increasing the ZR content to enhance root ADH and MDH activity, and to increase leaf chlorophyll content and photosynthetic rate.