施钾时期对食用甘薯光合特性和块根淀粉积累的影响

在施钾240 kg·hm^-2水平下，研究施钾时期对甘薯叶片光合特性和块根淀粉积累的影响.结果表明：与一次性施钾（全部基施）相比，分期施钾（1/2基施+1/2栽后75 d追施）提高了甘薯叶片的光合速率及叶片中磷酸蔗糖合成酶和块根中腺苷二磷酸焦磷酸化酶活性，提高了块根中淀粉积累速率(生育期平均增幅为6.7%)，显著增加了块根产量(增幅为8.2%).与不施钾处理相比，两个施钾处理均提高了叶片中蔗糖的合成能力和蔗糖在块根中转化为淀粉的能力.

Effects of potassium fertilization period on photosynthetic characteristics and storage root starch accumulation of edible sweetpotato

In this study, same amount of potassium (240 kg·hm^-2) was applied as basal dressing (treatment 1) and as 1/2 basal dressing + 1/2 top dressing at day 75 after planting (treatment 2), aimed to investigate the effects of potassium fertilization period on the photosynthetic characteristics of edible sweetpotato and the starch accumulation in storage root. As compared with treatment 1, treatment 2 improved the leaf photosynthetic rate and sucrose phosphate synthase activity and the storage root’s adenosine diphosphate glucose pyrophosphortlaseactivity, enhanced the starch accumulation rate in storage root (with an average increment of 6.7%), and increased the root tuber yield significantly by 8.2%. Both of the potassium fertilization treatments improved the synthesis of sucrose in leaf and the transformation from sucrose to starch in storage root, as compared with no potassium fertilization.