ABSTRACT

Water deficiency is the main bottleneck in potato production in many regions worldwide. The generation of higher tuber yields per unit of water is a key goal for both agronomists and potato growers. In this study, we found that under moderate deficit irrigation (DI; 50% relative water content (RWC)) at the seedling stage of potato growth, the leaf area index (LAI) and dry matter accumulation were lower than control; however, they caught up with and surpassed the control at later developmental stages with a normal water supply, and a higher yield was ultimately achieved. The LAI and total dry weight under severe water stress (35% RWC) also surpassed the control at harvest; however, the final yield remained low, due to the low distribution of dry matter into the tubers. Abscisic acid (ABA) increased under DI conditions at the seedling stage, while gibberellin (GA1 and GA3) levels decreased. Moreover, endogenous ABA increased as plant development proceeded from seedling stage to tuber initiation stage, regardless of water stress. Exogenous ABA application promoted dry matter accumulation and distribution into the tubers. Therefore, it may be that ABA, as a major signaling molecule, mediates water stress to regulate tuber sink capacity at early development period. Through a feedback regulation stronger source capacity was stimulated by sink enhancement mediated by moderate water stress at the seedling stage, reached a higher tuber yield finally by reestablishment of sink-source relationship.

摘要

缺水是全球许多地区马铃薯生产的主要瓶颈。每单位水产生更高的块茎产量是农学家和马铃薯种植者的关键目标。在本研究中，我们发现在马铃薯生长苗期中度亏缺灌溉（DI；50%相对含水量（RWC））下，叶面积指数（LAI）和干物质积累低于对照；但在发育后期，在正常供水的情况下赶上并超越了控制，最终获得了更高的产量。严重水分胁迫（35% RWC）下的 LAI 和总干重在收获时也超过了对照；然而，由于干物质在块茎中的分布很少，最终产量仍然很低。在幼苗期 DI 条件下，脱落酸 (ABA) 增加，而赤霉素（GA1和GA3）水平下降。此外，无论水分胁迫如何，随着植物发育从幼苗期到块茎萌发期，内源性 ABA 增加。外源ABA应用促进了干物质积累和分布到块茎中。因此，ABA作为主要的信号分子，可能在发育早期介导水分胁迫以调节块茎库容量。通过反馈调节，苗期适度水分胁迫介导的库增强刺激了更强的源能力，最终通过重建库源关系达到更高的块茎产量。外源 ABA 应用促进了干物质积累和分布到块茎中。因此，ABA作为主要的信号分子，可能在发育早期介导水分胁迫以调节块茎库容量。通过反馈调节，苗期适度水分胁迫介导的库增强刺激了更强的源能力，最终通过重建库源关系达到更高的块茎产量。外源 ABA 应用促进了干物质积累和分布到块茎中。因此，ABA作为主要的信号分子，可能在发育早期介导水分胁迫以调节块茎库容量。通过反馈调节，苗期适度水分胁迫介导的库增强刺激了更强的源能力，最终通过重建库源关系达到更高的块茎产量。