冬小麦节水栽培群体“穗叶比”及其与产量和水分利用的关系

建立高光效低耗水的群体结构是小麦节水高产栽培的核心内容.为此,需要明确节水高产群体的适宜调控指标.以穗叶比(单位面积穗数与上三叶总面积之比,穗/m2)为指标,在不同品种、不同灌水和种植密度条件下研究了小麦群体穗叶比的变化,并分析了穗叶比与群体光合性能、水分利用的关系.结果表明,在相同密度下,随着灌水减少,孕穗、开花和灌浆期的穗叶比均相应增大；在限水灌溉下,随密度增加穗叶比也相应增加.不同品种的穗叶比也存在明显差异.在适宜叶面积基础上,随穗叶比增加,群体中非叶面积指数(NAI)增加,冠层内光照状况明显改善,群体光合效率提高；非叶器官贮藏物质转移率增加,收获指数提高.在一定范围内,随穗叶比增加产量明显增加,而耗水量显著减少,从而使水分利用效率得到提高.研究认为,群体穗/叶比是衡量小麦节水栽培库源关系是否协调的适宜指标.试验中小麦节水省肥高产栽培适宜的穗叶比值为230-270穗/m2.

The ear-leaf ratio of population is related to yield and water use efficiency in the water-saving cultivation system of winter wheat

The key of water-saving and high-yield cultivation in wheat is to establish the population structure with high photosynthetic efficiency and low water consumption. For this reason, it is need to define the suitable control index of wheat population for water-saving and high-yield. In this paper, the ear-leaf ratio (the ratio of the number of ears to the total area of up 3 leaves in crop population, ears/m²) as a control index was studied including it''s variation and it''s relationships to photosynthetic performance of population and water use under the conditions of different varieties, irrigation treatments and planting densities. The results showed that, the ear-leaf ratios at the booting, anthesis and filling stage all increased as irrigation reduced or planting density increased. Under the condition of water-limited irrigation, there was significant difference in the ear-leaf ratio among varieties. On the basis of suitable leaf area, with the increase in the ear-leaf ratio, the non-leaf area index (NAI) of the population was increased, the illumination condition within the canopy was bettered obviously, the photosynthetic efficiency of the population was improved; the transfer percentage of reserves in non-leaf organs to grain was increased, the harvest index was increased; the yield was increased significantly and the water consumption was significantly decreased, which made the water use efficiency increase. Thus, it is put forward that the ear-leaf ratio of population is a suitable index to measure if the relationship between sink and source is compatible in the wheat water-saving cultivation system. The suitable ear-leaf ratio is 230-270 ears/m² in the water-saving, fertilizer-saving and high-yield wheat cultivation.