不同施钾量条件下甘薯块根形成的内源激素变化及其与块根数量的关系

Changes of endogenous hormones on storage root formation and its relationship with storage root number under different potassium application rates of sweet potato

为探讨不同施钾量条件下甘薯块根形成的内源激素变化及其与块根数量的关系,本试验以结薯数差异显著的鲜食型甘薯品种‘烟薯25’和‘北京553’为试验材料,以氧化钾(K2O)为供试肥料,设置0(K0)、120(K1)、240(K2)和360 kg hm-2(K3)4个钾肥梯度,研究不同施钾量对甘薯块根形成期粗根中的内源激素含量及相关代谢酶活性、收获期块根数量、块根整齐度等的影响。结果表明,与不施钾肥处理(K0)相比,施用钾肥降低了块根形成期粗根中吲哚乙酸氧化酶(indoleacetic acid oxidase,IAAO)、过氧化物酶(peroxidase,POD)的活性,提高了生长素(indole-3-acetic acid,IAA)含量;同时,增加了玉米素核苷(zeatin riboside,ZR)含量,降低了赤霉素(gibberellins,GA3)含量。施钾通过调控甘薯粗根中的内源激素水平,提升了初生形成层的活动能力,促进了不定根向块根的分化。与CK相比,增施钾肥显著提高了收获期烟薯25和北京553的单株结薯数与单薯重,提高了块根产量;烟薯25和北京553的单株结薯数增幅分别为3.16%~25.40%和3.85%~33.11%,产量增幅分别为4.22%~17.31%和3.94%~18.45%。2个品种各施钾处理相比,均为K2处理的单株结薯数最多,单薯重和块根产量最高,块根整齐度最好。

In order to explore the changes of endogenous hormones on storage root formation and its relationship with storage root number under different potassium application rates of sweet potato root,sweet potato varieties‘Yanshu 25’and‘Beijing 553’with significant differences in storage root number were used as experimental materials,potassium oxide(K2O)was used as fertilizer,and four potassium fertilizer gradients of 0(K0),120(K2),240(K3),and 360 kg hm-2(K4)were set.The effects of different potassium application rates on the contents of endogenous hormones,the activity of related metabolic enzymes,the number of storage root and root evenness in swelling roots of sweet potato during root formation and harvest stage were studied.Compared with the treatment without potassium fertilizer(K0),the application of potassium fertilizer decreased the enzyme activities of indoleacetic acid oxidase(IAAO)and peroxidase(POD),increased the content of indole-3-acetic acid(IAA),increased the content of zeatin riboside(ZR)and decreased the content of gibberellins(GA3).Potassium application enhanced the activity of primary cambium and promoted the differentiation from adventitious root to storage root by regulating the content of endogenous hormones in swelling roots of sweet potato.Compared with the control,the application of potash fertilizer significantly increased the number and weight of storage roots per plant and root yield of‘Yanshu 25’and‘Beijing 553’.The number of storage roots per plant of‘Yanshu 25’and‘Beijing 553’increased by 3.16%–25.40%and 3.85%–33.11%,respectively,and the yield increased by 4.22%–17.31%and 3.94%–18.45%,respectively.Compared with the potassium application treatments of the two varieties,the K2 treatment had the highest storage roots number per plant,the highest weight and yield of storage roots,with the best root evenness.