Alternation of wet and dry sides during partial rootzone drying irrigation alters root-to-shoot signalling of abscisic acid
Alternation of wet and dry sides during partial rootzone drying irrigation alters root-to-shoot signalling of abscisic acid
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DOI：
10.1071/fp06203
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发表时间：
2006-01-01
影响因子：
3
通讯作者：
Davies, William J.
中科院分区：
文献类型：
--
作者：
Dodd, Ian C.;Theobald, Julian C.;Davies, William J.
部分根区干燥(PRD)是一种灌溉技术，将水分不均匀地分配到根系，使部分灌溉，而其余部分被允许干燥土壤。番茄(Lycpers sice esculentum Mill.)将植物的根种植在两个土柱中，以比较PRD灌溉期间湿柱和干柱交替(PRD，PRD-A)与保持相同的湿柱和干柱(固定PRD，PRD-F)的生理后果。当PRD植株比水分充足的植株少受50%的水分时，木质部ABA浓度([X-ABA])增加，气孔导度降低。虽然两组PRD植株获得的水分相同，但PRD-A植株的[X-ABA]比PRD-F植株增加了2倍，这进一步降低了气孔导度。[X-ABA]的差异在交替的一小时内被检测到，但不会持续到交替的光周期之后。[X-ABA]随全盆土壤水分(theta(Pot))和叶水势(psi(Leaf))的下降而线性增加，但两组PRD植株间[X-ABA]的差异不是由于盆栽或psi(叶)的差异。在PRD-F植物中，随着土壤逐渐干燥，根系中未浇水的部分对蒸腾作用的贡献成比例地减少(姚等人。2001年，植物、细胞和环境24,227-235)。在PRD-A植物中，我们假设，重新给根系的干燥部分浇水允许这些根对总液流的贡献成比例地更大，从而在土壤干燥期间积累的根ABA库耗尽时，释放ABA脉冲到蒸腾流中。由于PRD-A引起的[X-ABA]的增加随着POT和PSI(叶)的下降而增加，为了最大化这种ABA脉冲的累积生理效应的最佳交替频率必须考虑到叶片水分的可能的负面影响。CIT随着土壤水分状况的下降而下降。
Partial rootzone drying ( PRD) is an irrigation technique where water is distributed unevenly to the root system such that part is irrigated while the remainder is allowed to dry the soil. Tomato ( Lycopersicon esculentum Mill.) plants were grown with their roots in two soil columns to compare the physiological consequences of alternation of wet and dry columns during PRD irrigation ( alternate PRD, PRD-A) with retention of the same wet and dry columns (fixed PRD, PRD-F). When PRD plants received 50% less water than well-watered ( WW) plants, xylem ABA concentration ([ X-ABA]) increased and stomatal conductance decreased relative to WW plants. Although both sets of PRD plants received the same amount of water, [ X-ABA] of PRD- A plants increased up to 2-fold above that of PRD- F plants, which further decreased stomatal conductance. Differences in [ X-ABA] were detected within an hour of alternation, but did not persist beyond the photoperiod of alternation. [ X-ABA] increased linearly as whole-pot soil water content (theta(pot)) and leaf water potential ( psi(leaf)) declined, but the difference in [ X-ABA] between the two sets of PRD plants was not due to differences in either pot or psi(leaf). In PRD- F plants, the unwatered part of the root system contributes proportionally less to the transpiration stream as the soil progressively dries ( Yao et al. 2001, Plant, Cell & Environment 24, 227 - 235). In PRD- A plants, we hypothesise that re-watering the dry part of the root system allows these roots to contribute proportionally more to total sap flux, thus liberating a pulse of ABA to the transpiration stream as the root ABA pool accumulated during soil drying is depleted. Since the enhancement of [ X-ABA] caused by PRD- A increased as pot and psi(leaf) declined, an optimal frequency of alternation to maximise the cumulative physiological effects of this ABA pulse must consider possible negative impacts of leaf water de. cit as soil water status declines.