| 摘要: |
| 【目的】探究钾肥种类及用量对紫花苜蓿抗寒性的影响及其与糖类物质变化的关系，旨在为紫花苜蓿秋季钾肥施用方案的制定提供理论依据。【方法】于2018年秋季的科尔沁沙地地区，以紫花苜蓿北极熊为供试品种，采用大田试验对紫花苜蓿施用K2SO4和KCl，钾肥（K2O）施用量分别为0，50，100，150，200 kg/hm2，于越冬前期挖取不同钾肥处理紫花苜蓿的根颈，人工模拟冷冻（-20 ℃）和冷藏（4 ℃）处理，测定紫花苜蓿根颈活力及可溶性糖、蔗糖、果糖、淀粉含量，并分析根颈活力与可溶性糖、蔗糖、果糖、淀粉含量之间的相关性。【结果】在相同钾肥及其用量下，冷冻处理紫花苜蓿根颈活力和淀粉含量均低于冷藏处理，但可溶性糖、蔗糖、果糖等糖类物质含量却高于冷藏处理。在冷冻处理条件下，施用150，200 kg/hm2 K2SO4（K2O）处理苜蓿的根颈活力、可溶性糖、蔗糖、果糖含量均高于施用KCl处理，K2SO4处理苜蓿根颈的淀粉含量显著低于KCl处理，在2种钾肥处理下，紫花苜蓿材料根颈活力、可溶性糖、蔗糖、果糖含量总体上以施用量为150 kg/hm2（K2O）最高，淀粉含量则以施用量为150 kg/hm2处理较低。相关性分析表明，苜蓿根颈活力与冷藏处理下的可溶性糖、果糖、淀粉含量呈显著或极显著正相关；与冷冻处理下的蔗糖、果糖呈显著或极显著正相关，与淀粉含量呈极显著负相关。【结论】在低温（-20 ℃）条件下，增施钾肥可以促进淀粉转化为蔗糖、果糖等可溶性糖类物质，从而提高紫花苜蓿的抗寒性，在科尔沁沙地施用150 kg/hm2 K2SO4（K2O）有利于紫花苜蓿的安全越冬。 |
| 关键词: 紫花苜蓿 钾肥 抗寒性 牧草栽培 施肥技术 |
| DOI： |
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| 基金项目:内蒙古自治区自然科学研究基金项目（2020MS03081）；内蒙古自治区科技储备项目(2018MDCB03)；国家自然科学基金项目（31960352） |
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| Effect of potassium fertilizer on cold tolerance and carbohydrate changes of alfalfa |
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CHEN Weidong,ZHANG Yuxia,CONG Baiming,et al
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| Abstract: |
| 【Objective】This study explored the effect of potassium fertilizer types and dosages on cold resistance of alfalfa and its relationship with changes in sugars to provide basis for the formulation of potassium fertilizer application to alfalfa in autumn.【Method】In autumn 2018,field experiment was conducted to apply K2SO4 and KCl to the alfalfa variety of ‘Gibraltar’ in the Horqin sandy land with potassium fertilizer (K2O) application rates of 0,50,100,150 and 200 kg/hm2,respectively.The root necks of alfalfa treated with different potassium fertilizer rates were excavated in the early overwintering period before artificially simulated freezing (-20 ℃) and cold storage (4 ℃) treatments.The root neck vitality and contents of soluble sugar,sucrose,fructose and starch were measured and their correlations were analyzed.【Result】Under same potassium fertilizer and dosage,the root neck vitality and starch content in frozen storage were lower than those in cold storage,but contents of soluble sugar,sucrose,fructose and other sugars were in opposite.Under freezing treatment,the root neck vigor and contents of soluble sugar,sucrose and fructose in 150 and 200 kg/hm2 K2SO4(K2O) treatments were higher than those in KCl treatment.The starch content of K2SO4 treatment was significantly lower than that of KCl treatment.In general,the root neck vitality and contents of soluble sugar,sucrose and fructose were the highest while starch content was the lowest when the application rate was 150 kg/hm2 (K2O).Correlation analysis showed that root neck vitality had significantly or extremely significantly positive correlation with soluble sugar,fructose and starch under cold storage and had significantly or extremely significantly positive correlation with sucrose and fructose under freezing storage.It also had extremely significantly negative correlation with starch.【Conclusion】Increased application of potassium fertilizer under low temperature conditions (-20 ℃) promoted the conversion of starch into soluble sugars such as sucrose and fructose,and thereby improved the cold resistance of alfalfa.Applying 150 kg/hm2 in the Horqin sandy land is beneficial to alfalfa for safe overwintering. |
| Key words: alfalfa potassium fertilizer cold resistance alfalfa cultivation fertilization technology |
