不同矿化度咸水灌溉对小麦产量和生理特性的影响

为充分利用河北低平原区蕴藏丰富的咸水资源,缓解淡水资源匮乏的矛盾,在连续定位灌溉田间试验的基础上,采用裂区设计,以灌溉水矿化度作为主处理,以不同小麦品种作为副处理,研究了不同矿化度梯度咸水灌溉对小麦产量、叶片相对电导率、丙二醛(MDA)含量、脯氨酸(Pro)含量以及叶片Na+、K+、Ca2+及K+/Na+等指标的影响及其与品种耐盐性的关系。研究结果表明,随灌溉水矿化度的增加叶片的细胞膜透性增强,同时膜脂氧化产物MDA增加、渗透调节物质脯氨酸增多、叶片中Na+累积增多,而高矿化度下Ca2+和K+/Na+比值明显降低;从品种的产量和耐盐指数来看,"石家庄8号"较"衡4399"表现较强的耐盐特性。从生理指标来看,"石家庄8号"较"衡4399"细胞膜更稳定,"衡4399"用2 g.L 1以上咸水灌溉其膜透性显著增加,而"石家庄8号"需要4 g.L 1以上咸水灌溉膜透性才显著提高。另外"石家庄8号"的耐盐性还与其维持较高的K+和较低的脯氨酸水平以及较高的K+/Na+比值有关,而与Na+、Ca2+绝对含量关系不明显。从MDA来看,返青期和孕穗期"石家庄8号"较"衡4399"水平低,但到抽穗期和灌浆期其积累量较"衡4399"反而要高。灌溉水的矿化度超过4 g.L 1时,两个小麦品种产量明显降低但耐盐性强的"石家庄8号"减产幅度相对较小。因此咸水灌溉小麦品种选择十分重要,从作物耐盐性和产量考虑,多年连续灌溉咸水的矿化度不宜超过4 g.L 1。

Impact of saline water irrigation with different salinities on yield and physiological indices of wheat

To make full use of salt water resources in minimizing the severity of scarcity of fresh water resources in the Low Hebei Plain, the impacts of salt water irrigation on wheat yield and selected leaf physiological indices were analyzed. The indices included relative electrical conductivity, MDA (malondialdehyde) content, Pro (proline) content, and concentrations of K⁺, Ca²⁺ and Na⁺, as well as K⁺/Na⁺ ratio. And their relationships with salt tolerance of wheat varieties were discussed too. The analysis was based on data from a long-term field trial of salt water irrigation. In the trial, the split-plot design was used with irrigation water salinity as main plots and wheat variety the sub-plots. The results showed that cell membrane permeability, MDA content, Pro content and Na+ concentration increased in leaves with increasing salinity of irrigation water. However, K⁺/Na⁺ ratio and Ca²⁺ concentration declined for increasing salinity treatments. Based on yield and salt tolerance index analysis, the "Shijiazhuang 8" variety was more salt-tolerant than "Heng 4399". For the physiological indices, "Shijiazhuang 8" cell membrane was more stable than "Heng 4399" cell membrane. For "Heng 4399", membrane permeability increased sharply at a irrigation water salinity of 2 g·L^-1. Sharp increase in membrane permeability of "Shijiazhuang 8" was only noted at a irrigation water salinity of 4 g·L^-. In comparison with "Heng 4399", salt tolerance characteristics of "Shijiazhuang 8" were related to its ability to maintain higher levels of K⁺ and K⁺/Na⁺ and lower levels of Pro, however, it was less related with Na⁺ and Ca²⁺ concentrations. For MDA level, "Shijiazhuang 8" was lower during reviving and booting periods compared with "Heng 4399", but higher during heading and milking periods. Yields of both "Shijiazhuang 8" and "Heng 4399" decreased significantly when irrigation water salinity was above 4 g·L^-1, but the decrease was always less in "Shijiazhuang 8" than in "Heng 4399" under similar treatments. With the continuous use of saline water irrigation, it was necessary to keep irrigation water salinity under 4 g·L^-1. Also choosing salt tolerant varieties was very critical for high harvest in the Low Hebei Plain.