THE EFFECT OF VARIATION IN SOIL-WATER AVAILABILITY, VAPOR-PRESSURE DEFICIT AND NITROGEN NUTRITION ON CARBON ISOTOPE DISCRIMINATION IN WHEAT
THE EFFECT OF VARIATION IN SOIL-WATER AVAILABILITY, VAPOR-PRESSURE DEFICIT AND NITROGEN NUTRITION ON CARBON ISOTOPE DISCRIMINATION IN WHEAT
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DOI：
10.1071/ar9920935
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发表时间：
1992-01-01
影响因子：
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通讯作者：
FARQUHAR, GD
中科院分区：
文献类型：
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作者：
CONDON, AG;RICHARDS, RA;FARQUHAR, GD
碳同位素鉴别（DELTA）是叶片蒸腾效率的一种综合测量方法，已被提出作为水资源有限环境下育种计划中提高水分利用效率的选择标准。本研究评估了土壤水分状况、蒸汽压亏缺和氮营养变化对植物干物质DELTA值的影响，以及常规小麦品种DELTA的环境和基因型变异的相对幅度。试验采用盆栽和大田种植的植物。两种基因型，cv。克利奥帕特拉和雅奎50E，在大（23升）容器中生长，以模拟田间条件。植物受到不同的浇水制度，不同水平的大气需求（通过在室外种植植物和不同的播种时间）和两种水平的氮营养（相当于150和30公斤N ha-1）。在新南威尔士州西南部的Moombooldool进行了一项使用8种基因型的田间试验，该地区的年降雨量和分布与东南小麦带的大部分地区是典型的。DELTA在整个季节的变化之后，对最近扩大的植物部分进行采样。在田间种植的植物中，在早期形成的叶片和籽粒之间测定的干物质DELTA下降了5 × 10（-3）。在容器种植的植物中也观察到类似的变化（7 × 10(-3)）。对于田间和容器栽培的植物，对DELTA的环境影响归因于气孔关闭，以响应土壤水分下降和/或蒸汽压赤字增加。容器栽培植物低氮营养使成熟期地上部干物质和旗叶出苗期叶面积减少30%，对叶片δ值的影响较小，但变化不大。田间试验中，不同植株部位DELTA基因型间差异均显著，典型变异为c. 1.8X10（-3）。DELTA的基因型排序随植株部位的不同而变化，但基因型与环境交互作用的幅度相对于DELTA的遗传变异较小。排名的变化主要发生在赛季后半段。这主要归因于基因型间土壤干燥速率和程度的差异。开花期土壤水分耗竭程度的变化与季节前期埋设植株部位的δ呈显著正相关。
Carbon isotope discrimination (DELTA) is an integrative measure of leaf transpiration efficiency and has been proposed as a select criterion for greater water-use efficiency in breeding programs for water-limited environments. Here we assess the effects of variation in soil water status, vapour pressure deficit and nitrogen nutrition on the value of DELTA measured in plant dry matter and the relative magnitudes of environmental and genotypic variation in DELTA among conventional wheat cultivars.Experiments were done using container- and field-grown plants. Two genotypes, cv. Cleopatra and Yaqui 50E, were grown in large (23 L) containers to simulate field conditions. Plants were subjected to contrasting watering regimes, to different levels of atmospheric demand (by growing the plants outdoors and varying sowing time) and to two levels of nitrogen nutrition (equivalent to 150 and 30 kg N ha-1). A field experiment using eight genotypes was conducted at Moombooldool in south-west New South Wales, which has an annual rainfall total and distribution typical of much of the south-east wheat belt. Changes in DELTA over the course of the season were followed by sampling recently expanded plant parts.In field-grown plants DELTA measured in dry matter fell by 5x10(-3) between early-formed leaves and the grain. A similar change (7x10(-3)) was observed in container-grown plants. For both field- and container-grown plants, environmental effects on DELTA were attributed to stomatal closure in response to declining soil water and/or increasing vapour-pressure deficit. Low nitrogen nutrition of container-grown plants, which reduced above-ground dry matter at maturity and leaf area at flag leaf emergence by 30%, had a small but variable effect on the value of DELTA.In the field experiment, variation among genotypes in DELTA of different plant parts was always significant, and was typically c. 1.8X10(-3). Genotype ranking for DELTA changed with different plant parts, but the magnitude of genotype x environment interaction was small in relation to genetic variation in DELTA. Changes in ranking mainly occurred in the latter half of the season. These were attributed primarily to differences in the rate and extent of soil drying among genotypes. Variation in the extent of soil water depletion measured at anthesis was positively correlated with DELTA of plant parts laid down early in the season.