种植方式对冬小麦光合特性及理化性质的影响

Impact on Photosynthetic Characteristics of Winter Wheat Planting Patterns and Physicochemical Properties

[目的]通过盆栽实验,探讨不同种植方式下冬小麦在水分胁迫期间光合特性和理化性质的变化及它们之间的相关性,以期为旱地节水农业的持续发展提供理论及实践上的依据。[方法]在冬小麦花期水分胁迫自然加重条件下,选择5个时间点,每点按3次重复随机选取各处理小麦旗叶,测定其叶绿素荧光诱导动力学参数与叶片丙二醛和脯氨酸含量。[结果]水分胁迫下各处理冬小麦Fv/Fm与Fv/F0值均降低,且两者呈显著正相关关系。单播时,耐旱性强的A品种Fv/Fm、Fv/F0下降幅度与丙二醛、脯氨酸增加幅度均明显小于耐旱性弱的B品种;混播时,两品种间各指标变化幅度差异减小。同一品种不同种植方式相比较,单播时的A品种Fv/Fm、Fv/F0下降幅度与丙二醛增加幅度小于混播状态,脯氨酸增加幅度大于混播状态;单播时的B品种Fv/Fm、Fv/F0下降幅度与丙二醛、脯氨酸增加幅度均大于混播状态。单播方式下叶片脯氨酸含量与Fv/Fm之间的显著相关关系存在于耐旱性弱的B品种,而不存在于耐旱性强的A品种,混播方式下这种相关关系被打破。丙二醛含量与Fv/Fm之间无论品种和种植方式的改变其相关均不显著。[结论]单一种植时耐旱性越强的品种对水分胁迫(干旱)的反应越不敏感,对干旱的防御机制也越健全,混合种植时耐旱性强的品种反而由于其个体水分竞争力较弱,使其受水分胁迫程度加剧,抑制了耐旱力的发挥。耐旱力较弱的品种则在这种竞争中由于其较强的水分竞争力而受益,减弱了水分胁迫对其生理的抑制,也使得品种间的耐旱性差别有所减小。另外,不能单独将脯氨酸含量作为植物抗旱性的评价指标。

[ Objective ] Through pot experiment, winter wheat under different planting patterns under the water stress was chosen to study photosynthetic characteristics and the correlation among the changes of the physicochemical properties, in order to provide theoretical and practical basis for the sustainable development of water saving agriculture in dry lands. [ Method] When water stress of winter wheat was naturally increased at flowering, five points were chosen in time conditions, and each point was repeated three times. Flag leaves of wheat were randomly selected in each treatment to determine the parameters of chlorophyll fluorescence induction kinetics and MDA and proline content. [ Result] Fv/Fm and Fv/Fo of winter wheat under water stress were decreased, and both had a significantly positive correlation. At single sowing, Fv/Fm and Fv/Fo of strong drought tolerant variety A decreased with MDA, and proline content increased significantly less than that of weak drought tolerance variety of B. At mixed sowing, differences of every index of two varieties were reduced. At different ways of planting the same variety, the decrease of Fv/Fm and Fv/Fo and the increase of MDA content at single sowing of variety A were lower than those at mixed sowing, and the increase of proline content was higher than that at mixed sowing. The decrease of Fv/Fm and Fv/Fo and the increase of MDA and proline content at single sowing of variety B were higher than those at mixed sowing, A significant correlation between proline content and Fv/Fm at single sowing existed in the weak drought tolerance variety B, but didn＇ t exist in the drought resistant variety A. At mixed planting mode, this relationship was broken. The correlation between MDA and Fv/Fm under the change of varieties and planting pattern wasn＇ t signif icant. [ Conclusion] At single sowing, the response？ of cnltivars which had stronger drought tolerance to water stress （drought） wasn＇ t sensi tive to drought, and defense mechanism was more perfect. At mixed planting mode, because individual water competitive influenced by the de gree of water stress of cultivars which had drought resistance was low, the drought tolerance was inhibited. But among the competition, the cul tivars which had weak drought resistance had the benefit. The inhibition of water stress on the physiological drought tolerance was reduced, and the difference between varieties was decreased. In addition, the proline content alone couldn＇ t be used as evaluation index of drought re sistance of the plant.