土壤水分对春小麦碳同位素分馏与矿质元素K、Ca和Mg含量的影响

THE EFFECT OF SOLL WATER CONDITIONS ON CARBON ISOTOPE DISCRIMINATION AND MINERALS CONTENTS IN SPRING-PLANTED WHEAT

碳同位素分馏(Δ13C)是小麦蒸腾效率和产量较好的间接选择指标,但是由于Δ13C的测定分析成本较高,寻找与之密切相关的替代指标十分必要,灰分含量(ma)是一个公认的Δ替代指标。为了验证春小麦营养器官中灰分及其中主要矿质元素含量与Δ13C的关系,进行了3个水分处理的盆栽试验,即45%±5%,55%±5%和75%±5%田间持水量(FC)。结果发现:测定的指标在不同的水分处理间有显著差异,不同来源的基因型间碳同位素分馏有较大的差异,水地育成的品种或高代材料具有较高的Δ13C值,而旱地育成的品种或当地古老品种则表现出了较低的Δ13C值。在重度水分胁迫处理(T1)条件下,拔节期小麦地上整株、倒二叶以及扬花期旗叶中的灰分含量与旗叶Δ13C呈显著正相关(r=0.790,P<0.01;r=0.788,P<0.01;r=0.656,P<0.05)。在中度水分胁迫处理(T2)下,扬花期旗叶中的钾(K)含量与Δ13C呈显著负相关(r=0.813,P<0.01);在中度水分胁迫处理(T2)和正常灌水处理(T3)下,扬花期旗叶中镁(Mg)的含量与Δ13C呈显著正相关(r=0.725,P<0.05;r=0.826,P<0.01);在正常灌水处理(T3)下,扬花期旗叶中钙(Ca)的含量与Δ13C呈显著正相关(r=0.708,P<0.05)。在水分胁迫条件下叶片或地上整株中的灰分含量是Δ较好的替代指标,而旗叶中K、Mg和Ca的含量在中度水分胁迫和正常供水条件下能够较好地预测Δ值。

Carbon isotope discrimination （Δ13 C） has and grain yield in wheat. However, because of high screening criteria. Ash content （mo） has been p been proposed as indirect selection criterion for transpiration cost for Δ13C analysis, attempts have been made to identify efficiency alternative as an alternative criterion for A13C in wheat and barley. A pot experiment with three water treatments （45% ± 5% FC, 55% ± 5%FC and 75% ± 5%FC） was conducted and flag leaf Δ13C （ΔLa）, contents of ash, potassium （K）, magnesium （Mg） and calcium （Ca） were measured to study the relationships between A, mineral composition in spring planted bread wheat （ Triticum aestivum L. ）. In the light of the results obtained in this research, the traits measured showed significant differences among the three water treatments. There were variations in ΔLa between the genotypes derived from contrasting environments. The improved varieties or advanced lines bred in irrigated areas displayed higher Δ13C values, while the improved and local varieties bred in rain-fed areas exhibited lower Δ13C values. Significant positive correlations were found between Δ13C and ma in seedlings and second fully developed leaves at elongation stage and in flag leaves at anthesis stage in severe drought treatment （TI ） （ r = 0.790, P 〈 0.01 ; r = 0.788, P 〈 0.01 ; r = 0.656, P 〈 0.05, respectively）. A13 C was negatively associated with potassium （K） content in flag leaves in T2 （ r = 0. 813, P 〈 0.01 ） and positively with magnesium （Mg） content in flag leaves in T2 and T3 （ r = 0. 725, P 〈 0.05 ; r = 0. 826, P 〈 0.01, respectively） at anthesis. Significant positive correlation between Δ13C and calcium （Ca） content in flag leaves in T3 （r = 0. 708, P 〈 0.05） was also found in this study. These results suggested that mo is a possible alternative criterion of Δ13C in vegetative organs especially in stressed environments. K, Mg and Ca contents in flag leaf under moderate water stress or feasible water conditions might be new predictive criteria of ALa .