5-ALA对苹果花粉萌发生长的抑制作用和疏花效应

Inhibitory effects of 5⁃aminolevulinic acid on Apple pollen germination and growth,and its thinning effects on flowering

[目的]研究5-氨基乙酰丙酸(5-aminolevulinic acid,简称5-ALA)对苹果疏花的作用,减少农场劳动力使用和成本投入。[方法]在苹果园疏花试验中喷施不同浓度的5-ALA,试验出苹果园疏花的最佳浓度;通过不同浓度5-ALA在授粉前后不同时间间隔处理柱头,以获得5-ALA的最佳使用时间;并通过离体培养不同浓度的5-ALA溶液对花粉粒萌发和花粉管生长的影响,进一步验证其对苹果的疏花效应和使用浓度。[结果]用0~400 mg·L^(-1)的5-ALA处理苹果盛花期的花枝,其中疏花效果最好的是200和400 mg·L^(-1)的5-ALA,坐果率仅为19.1%和21.6%,可以达到人工疏花的效果。在0~200 mg·L^(-1)的5-ALA溶液花粉萌发试验中,10 mg·L^(-1)的5-ALA可以对花粉的萌发起到促进作用,10 mg·L^(-1)的5-ALA明显使得花粉粒萌发率和花粉管的长度更加长,萌发率也比对照高了8.8%。而20、50、100 mg·L^(-1)的5-ALA均可以对花粉的萌发起到抑制作用,萌发率比对照低了约30%~40%;而200和400 mg·L^(-1)的5-ALA处理下,花粉粒几乎不萌发。虽然低浓度的5-ALA的确促进花粉的萌发(如10 mg·L^(-1)),但试验中其它浓度的5-ALA也可以降低花粉的萌发率和花粉管长度;而且授粉后24 h内喷施5-ALA是对苹果疏花效果最好的时候。[结论]与对照相比,200和400 mg·L^(-1)的5-ALA确实对苹果花粉有抑制萌发生长和疏花的作用,同时会对苹果的疏花成本有所降低,并且提高了果实品质,建议在黄土高原苹果园示范推广。

[Objective]The thinning effects of 5-aminolevulinic acid(5-ALA)on apple trees was studied with the aims to reduce labor and cost inputs in orchard management.[Methods]In the experiment,different concentrations of 5-ALA were sprayed during the thinning experiment in apple orchards to determine the optimal concentration for thinning;The stigmas were treated with different concentrations of 5-ALA at different time intervals before and after pollination to determine the best use timing for 5-ALA application.Additionally,in vitro cultures were conducted using different concentrations of 5-ALA solution to examine their effects on pollen germination and pollen tube growth,further validating their thinning effect and appropriate concentration on apple trees.[Results]Spraying apple branches during the flowering stage with 5-ALA concentrations ranging from 0 to 400 mg·L^(-1)revealed that the most effective thinning effect was observed at 200 and 400 mg·L^(-1),resulting in fruit set rates of only 19.1%and 21.6%,respectively,which achieved a comparable effect to manual thinning.In the pollen germination test using 0 to 200 mg·L^(-1)5-ALA solutions,a concentration of 10 mg·L^(-1)promoted pollen germination,significantly increasing both ger-mination rate and pollen tube length,with a germination rate 8.8%higher than the control.However,concentrations of 20,50,and 100 mg·L^(-1)5-ALA exhibited inhibitory effects on pollen germination,reducing the germination rate by approximately 30%~40%.Under the treatment of 200 and 400 mg·L^(-1)5-ALA,pollen grains hardly germinated.Although low concentra-tions of 5-ALA did promote pollen germination,such as 10 mg·L^(-1),subsequent experiments have shown that other concentra-tions of 5-ALA in the experiments also reduced the germination rate and pollen tube length.Moreover,spraying 5-ALA 24 hours after pollination yielded the best thinning effect on apple trees.[Conclusion]Compared to the control,concentration of of 200 and 400 mg·L^(-1)5-ALA indeed exhibited inhibitory effects on apple pollen germination and growth,resulting in effective thinning while reducing thinning costs and improving fruit quality.these findings suggested that the application of 5-ALA in the apple orchard in the Loess Plateau is recommended for demonstration and promotion.