小麦品种抗旱性与深根性和深层根系活性的关系

为明确小麦根系垂直生长与抗旱能力的关系,以不同抗旱类型品种洛旱6号、西农979和郑麦366为材料,在柱栽条件下研究了不同生育时期最大根深、根干重垂直分布、根系活性垂直变化等性状。结果表明,本试验条件下,小麦根深在挑旗期达最大值,越冬至挑旗期间根系生长速度快。挑旗期和抽穗期不同抗旱类型品种间根深差异显著,其中抗旱性强的品种最大根深较大;与抗旱性弱的品种相比,抗旱性强的品种总根干重和深层根干重小,根系生理活性强。籽粒灌浆期表现为抗旱性越强,深层根系生理活性越强。据此认为,抗旱性强的小麦品种未必具有较大的根干重或深层根干重,但其根系下扎深且深层根系生理活性较强,尤其是生育后期的根系生理活性强。

Relationship between Drought Resistance,Deep Rooting Characteristics and Vigor of Roots within Deep-Soil-Layer of Different Wheat Cultivars

Due to the difficulty to obtain complete or intact root samples,there were only few studies focusing on growth and vertical distribution of wheat root system,so that researchers know little about the relationships between drought resistance and root vertical growing.The objective of this study is to verify the relationship between wheat root growing and vertical distribution characteristics of different cultivars.Using Luohan 6 (a wheat cultivar with strong drought tolerance),Xinong 979 (a wheat cultivar with drought tolerance) and Zhengmai 366 (a wheat cultivar with weak drought tolerance) as the experimental materials,the soil cylinder experiment was conducted under the rainshed to study the maximum root depth,vertical distribution of dry root weight,and vigor of roots at different soil layers at different growing stages.The results showed that root depth of winter wheat reached the maximum at flag-leaf expansion stage in this study,and root grew fastest from wintering stage to flag-leaf expansion stage.Difference in the maximum root depth among three wheat cultivars with different drought resistance was significant,both at flag-leaf expansion stage and heading stage.The maximum root depth of Luohan 6 was deeper than that either of Xinong 979 or Zhangmai 366.Compared with Zhengmai 366,Luohan 6 had less total dry root weight per plant and less dry weight of deep-soil-layer roots,but had stronger root vigor.At grain-filling stage,the stronger drought resistance a wheat cultivar had,the stronger vigor of deep-soil-layer roots was.A drought-resistant wheat cultivar may not necessarily have more dry weight of roots per plant and dry weight of deep-soil-layer roots,but surely have the deeper rooting depth and stronger vigor of roots,especially the root vigor during the late growing period.