Soil moisture heterogeneity during deficit irrigation alters root-to-shoot signalling of abscisic acid
Soil moisture heterogeneity during deficit irrigation alters root-to-shoot signalling of abscisic acid
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DOI：
10.1071/fp07009
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发表时间：
2007-01-01
影响因子：
3
通讯作者：
Dodd, Ian C.
中科院分区：
文献类型：
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作者：
Dodd, Ian C.
比较了不同灌溉方式对番茄叶片木质部ABA浓度（[X-ABA]（叶片））的影响。在部分根区干燥（PRD）过程中，水分在根系中的分布不均匀，部分用于灌溉，其余部分用于干燥土壤。在常规亏缺灌溉（DI）条件下，植株吸收的水量与珠三角植株相同，但水分在整个根系中分布均匀。当植物根系被允许探索两个不同的土壤区室时，在土壤中度干燥的情况下，DI植物的[X-ABA]（叶片）高于PRD植物，但随着土壤进一步干燥，PRD植物的[X-ABA]（叶片）高于DI植物。两组植株叶片中[X-ABA]含量的差异不是由于全盆土壤含水量（theta pot）或叶片水势（psi leaf）的差异造成的。为了研究根系不同部位对[X-ABA]（叶片）的贡献，我们将单个枝条嫁接到两个盆栽植株的根系上，使嫁接结合呈倒“Y”形。从离体叶片中收集汁液后，除去嫁接接穗以下的枝条，可以从每个根系中收集汁液。同样，在土壤相对湿润时，DI植物的[X-ABA]（叶片）高于PRD植物，而在土壤相对干燥时则相反。根木质部KABA浓度（[X-ABA]（根））随土壤含水量（θ）的降低呈指数增长。在DI植物中，来自盆栽的[X-ABA]（根）（或[X-ABA]（根）的算术平均值）对[X-ABA]（叶）的变异量的影响相似。在PRD植物中，来自水侧的[X-ABA]（根）低估了[X-ABA]（叶），而来自干侧的[X-ABA]（根）高估了[X-ABA]（叶）。[X-ABA]（根）的算术平均值最好地解释了[X-ABA]（叶）的变化，这意味着在土壤水势（psi土壤）下，根系的干燥部分（J（干））继续流出汁液，而在以前对珠三角植物的研究中，J（干）在土壤水势（psi土壤）下停止流动（Yao et al. 2001）。评估J（干燥）和psi（土壤）之间的关系可能有助于维持根系干燥部分ABA（和其他生长调节剂）的输出，从而在珠江三角洲期间实现理想的园艺成果。
The effects of different irrigation techniques on leaf xylem ABA concentration ([X-ABA](leaf)) were compared in tomato (Lycopersicon esculentum Mill.). During partial rootzone drying (PRD), water was distributed unevenly to the root system such that part was irrigated while the remainder was allowed to dry the soil. During conventional deficit irrigation (DI), plants received the same volume of water as PRD plants, but water was distributed evenly to the entire root system. When the plant root system was allowed to explore two separate soil compartments, DI plants had a higher [X-ABA](leaf) than PRD plants with moderate soil drying, but PRD plants had a higher [X-ABA](leaf) than DI plants as the soil dried further. The difference in [X-ABA](leaf) between the two sets of plants was not because of differences in either whole pot soil water content (theta pot) or leaf water potential (psi leaf). To investigate the contribution of different parts of the root system to [X-ABA](leaf), individual shoots were grafted onto the root systems of two plants grown in two separate pots, so that the graft union had the appearance of an inverted 'Y'. After sap collection from detached leaves, removal of the shoot below the graft union allowed sap collection from each root system. Again, DI plants had a higher [X-ABA] (leaf) than PRD plants when the soil was relatively wet, but the opposite occurred as the soil dried. Root xylem KABA concentration ([X-ABA](root)) increased exponentially as soil water content (theta) declined. In DI plants, [X-ABA](root) from either pot (or the arithmetic mean of [X-ABA](root)) accounted for a similar amount of the variation in [X-ABA](leaf). In PRD plants, [X-ABA] (root) from the watered side underestimated [X-ABA](leaf), whereas [X-ABA](root) from the dry side overestimated [X-ABA](leaf). The arithmetic mean of [X-ABA](root) best explained the variation in [X-ABA](leaf), implying continued sap flow from the dry part of the root system (J(dry)) at soil water potentials (psi soil) at which J(dry) had ceased in previous studies of PRD plants (Yao et al. 2001). Evaluating the relationship between J(dry) and psi(soil) may assist in maintaining export of ABA ( and other growth regulators) from the drying part of the root system, to achieve desirable horticultural outcomes during PRD.