施钾对甘薯贮藏期腐烂率及碳水化合物变化的影响

Effect of potassium application on the decay rate and carbohydrate of sweetpotato during storage

为探究甘薯最宜施钾浓度以期延长甘薯贮藏和保持较好的营养品质,以‘商薯19’和‘心香’2个品种为材料,设置0 kg/hm^(2)(K_(0))、75 kg/hm^(2)(K_(1))、150 kg/hm^(2)(K_(2))、225 kg/hm^(2)(K_(3))和300 kg/hm^(2)(K_(4))5个钾肥(K_(2)O)浓度在扦插及扦插30 d后施用。甘薯块根收获、愈伤后贮藏于14℃、相对湿度为85%的环境中,测定贮藏0、15、30、60和90 d的腐烂率、营养品质以及淀粉酶活性。结果表明:K_(2)处理的‘商薯19’和K_(3)处理的‘心香’耐贮性较好,腐烂率最低,分别为18.25%和23.00%;‘商薯19’和‘心香’在贮藏期内二者淀粉含量总体呈先下降后上升的趋势,可溶性糖含量总体呈先上升后下降的趋势。其中,K_(2)处理的‘商薯19’淀粉含量最高,为82.05%。K_(3)处理的‘心香’果糖和葡萄糖含量显著高于其他处理。因此,在甘薯生长过程中,施用150 kg/hm^(2)浓度的钾肥(K_(2)O)能有效降低其在贮藏期内的腐烂率,保持较好的营养品质。

In order to investigate the effects of potassium application on root rot rate and carbohydrate content of sweet potato during storage,sweet potato varieties‘Shangshu19'and‘Xinxiang'were taken as study materials.Five potassium rates(0,75,150,225,300 kg/hm^(2),named as K_(0),K_(1),K_(2),K_(3) and K_(4),respectively)were applied at cutting day and 30 days after cutting.The rot rate,nutritional quality and amylase activity of sweet potato roots were measured at 14℃ and 85% relative humidity for 0,15,30,60 and 90 days after storage.The results showed that:‘Shangshu19'of K_(2) treatment and‘Xinxiang'of K_(3) treatment displayed better storability performances at 18.25% and 23%.During the storage,the starch contents of‘ShangShu19'and‘Xinxiang'decreased firstly and increased afterwards,while the soluble sugar content firstly increased and then decreased.Among them,the starch content of‘ShangShu19'of K_(2) treatment was the highest at 82.05%.The fructose and glucose content of‘Xinxiang'of K_(3) treatment was significantly higher than those in other treatments.Therefore,application of potassium fertilizer(K_(2)O)at the concentration of 150 kg/hm^(2) can effectively reduce the rot rate of sweetpotato during storage and maintain good nutritional quality.