不同时期干旱胁迫对甘薯内源激素的影响及其与块根产量的关系

在人工控水条件下, 以抗旱品种济薯21和不抗旱品种济紫薯1号为试验材料, 设置全生育期干旱胁迫(DS)、发根分枝期干旱胁迫(DS1)、蔓薯并长期干旱胁迫(DS2)、快速膨大期干旱胁迫(DS3) 4个处理, 全生育期正常灌水(WW)为对照, 研究其对甘薯内源激素及块根产量的影响。结果表明, 与对照相比, 2个品种不同年份的所有干旱胁迫处理的鲜薯和薯干产量均显著下降。其中, DS薯干产量减产幅度最大, 济薯21和济紫薯1号3年平均分别减产44.62%和56.21%; 其次是DS1, 减产32.03%和44.03%; 再次是DS2, 减产30.41%和39.39%; DS3的减产幅度最小, 为13.66%和17.88%。抗旱品种济薯21的减产幅度小于不抗旱品种济紫薯1号。干旱胁迫抑制了甘薯地上部生长及块根的形成和膨大, 两个品种的单株叶片数、蔓长、地上部干重、地下部干重和块根淀粉率, 与对照相比, 各时期均表现为, DS的减少幅度最大, 其次是DS1和DS2, DS3的减少幅度最小。不同时期干旱胁迫均引起叶片和块根中GA、IAA和ZR含量下降, ABA含量上升。地上部干重与叶片GA、IAA和ZR含量呈显著正相关, 与ABA含量呈显著负相关; 地下部干重与块根GA、IAA和ZR含量呈显著正相关, 与ABA含量呈显著负相关。总之, 不同时期干旱胁迫均导致甘薯产量下降, 且胁迫时间越早, 对甘薯内源激素和块根产量的影响越大, 发根分枝期是甘薯对水分最敏感的时期。

Effects of Drought Stress at Different Growth Stages on Endogenous Hormones and Its Relationship with Storage Root Yield in Sweetpotato

Field experiments were conducted under a rain exclusion shelter using two sweetpotato (Ipomoea batatas (L.) Lam) cultivars (Jishu 21, drought-tolerant, and Jizishu 1, drought-sensitive) with four drought stress treatments during the whole growth period (DS), root branching stage (DS1), the intermediate stage (storage root initiation) (DS2), and the final stage (storage root bulking) (DS3). A sep-arate well watered experiment was as a control (WW). Compared with the control, the fresh and dry weight of two cultivars in all treatments decreased significantly in three years. The dry weight of DS treatment had the highest decrease, with an average of 44.62% and 56.21% for Jishu 21 and Jizishu 1, respectively. The impact of DS1 was the second, with an average decrease of 32.03% and 44.03% for Jishu 21 and Jizishu 1, respectively, followed by DS2, with an average decrease of 30.41% and 39.39%, respectively. The impact of DS3 was the lowest, with an average decrease of 13.66% and 17.88%, respectively. The impact of drought stress on dry weight of Jishu 21 was lower than that of Jizishu 1. The drought stress significantly inhibited the growth of aboveground part, and the formation and bulking of storage roots. Number of leaves per plant, vine length, dry weight of aboveground and underground parts, and starch content were decreased under drought stress, compared with the control. DS had the highest impact, followed by DS1 and DS2; DS3 had the lowest impact. GA, IAA, and ZR contents in leaves and roots of both cultivars decreased, while ABA content increased. There were significant positive correlations between dry weight of aboveground part and GA, IAA, and ZR contents in leaves, dry weight of underground part and GA, IAA, and ZR contents in storage roots. However, ABA content in leaves and storage roots was negatively correlated with dry weight of aboveground part and underground part, respectively. In summary, drought stress applied during different growth stages reduced the yield of fresh and dry roots. The earlier the application of drought stress, the greater influence on levels of endogenous hormones and storage root yields. Root branching stage of sweetpotato is most sensitive to drought stress.