拉枝对玉露香梨枝条生长及果实糖含量和蔗糖代谢酶活性的影响OA

[Objective]The study aimed to analyze the effects of branch bending angle on branch growth and sugar metabolism and accumulation in Yuluxiangli under a trellis cultivation mode,providing a theoretical ba-sis for improving fruit quality.[Method]Using Yuluxiangli in trellis cultivation mode,branch bending treat-ments at 30°,60°,and 90° were applied to the main extension branches of the trellis.Unbent branches served as the control.Fruit setting rate and branch composition were calculated,and length and diameter of the new shoots of the main extension branches,single fruit weight,longitudinal and transverse diameters of fruits at maturity were measured.Fruit sugar contents(soluble sugars,fructose,sucrose,glucose,and sorbitol)and activities of su-crose metabolizing enzymes(sucrose phosphate synthetase(SPS),sucrose synthetase(SS-Ⅱ),neutral inver-tase(NI),and acid invertase(AI))were quantified.[Result]The larger the branch bending angles of the main branch of Yuluxiangli in tre-llis cultivation mode,the slower the growth of the new shoot.All branch bending treatments increased fruit setting rate,having no significant effect on the composition of branches.At a 60° bend-ing angle,fruit setting rate and ratios of medium and short branches increased,while ratios of long branches de-creased.With the increase of bending angle,the transverse and longitudinal diameters of fruit first increased and then decreased.With fruit ri-pening,the transverse diameter,longitudinal diameter and single fruit weight gradu-ally increased,reaching the maximum value at maturity.In the middle and later stages of fruit ripening,fructose and glucose contents increased rapidly,with fructose becoming the predominant sugar in fruit.The sweetness in-dex first increased and then decreased,peaking at 80 d,a trend consistent with fructose content dynamics.In early fruit development,acid invertase(AI)and neutral invertase(NI)activities remained low,but increased gradually with fruit development.Sucrose synthetase(SS-Ⅱ)activity decreased in early development,but in-creased during later stages.Sucrose phosphate synthetase(SPS)activity increased continuously throughout fruit development.[Conclusion]The 60° branch bending treatment was beneficial to increase the fruit setting rate and ratios of medium and short shoots in trellised Yuluxiangli pear trees.It promoted leaf photosynthetic efficiency,and more effectively enhanced the sugar accumulation and activities of sucrose metabolizing enzymes in fruits.