水分调控对冬小麦根系生长及抗旱性的影响

为了研究干旱半干旱地区土壤剖面深层水分对冬小麦根系生长及抗旱性的影响,采用PVC管土柱法进行冬小麦生长水分调控试验,设计了4个处理,即处理Ⅰ为地面灌溉、处理Ⅱ为计划湿润层取根系分布深度的60%、处理Ⅲ为计划湿润层取根系分布深度的75%、处理Ⅳ为计划湿润层取根系分布深度的90%,测定了冬小麦各生育期根系形态指标和地上部分植株体干重的变化,结果表明:灌水总量一定,改变灌水方式、考虑计划湿润层的深层灌溉,能够促进冬小麦根系深扎,至成熟期,处理Ⅱ、Ⅲ、Ⅳ的根长比处理Ⅰ长27~37 cm,总根干重均增加,但根冠比减小,产量增加。适宜的根冠比能更好地协调冬小麦地上部分与地下部分之间生长关系,提高抗旱能力。处理Ⅱ和处理Ⅲ是冬小麦根冠层生长协调、提高抗旱能力较适宜的灌溉方案,可为我国北方地区冬小麦节水灌溉提供参考。

The Influence of Water Regulation on Root Morphology and Drought Tolerance of Winter Wheat

The aim of this study is to assess the effects of deep soil water on winter wheat root morphology and drought tolerance in the arid and semi-arid by using different planned irrigation wetting depths.Four water levels were set up in a pot experiment using PVC tubes, namely, surface irrigation (Ⅰ), irrigation wetting depth of 60％ root distribution (Ⅱ), irrigation wetting depth of 75％ root distribution (Ⅲ), and irrigation wetting depth of 90％ root distribution (Ⅳ).The root morphology indexes and above ground dry weight were measured to evaluate the plant growth.The results showed that the deep irrigation which changed the irrigation method from surface to plan wetting depth of root distribution could improve the down depth of winter wheat rooting under the condition of same precipitation rate.At the maturity stage, the Ⅱ,Ⅲ and Ⅳ treatments produced deeper root systems to 27～37 cm, and had higher total root dry weight and grain yield than the Ⅰ treatment.In contrast, the root to shoot ratio decreased for the Ⅱ, Ⅲ or Ⅳ treatment, because appropriate root-shoot ratio could better coordinate the relationship between the aerial and underground part of winter wheat and improve drought tolerance.Therefore, the root distribution depth of 60％ (Ⅱ) and 75％ (Ⅲ) under the experimental conditions were more suitable irrigation scheme, and could provide a reference for water-saving irrigation of winter wheat in North China.