不同群体结构夏玉米灌浆期光合特征和产量变化

大田试验以夏玉米为试料,采用裂裂区试验设计,密度设计包含75000、90000\,105000株/hm² 3个密度作为主区,每个密度处理包括: ①等行距60 cm×单株留苗,②等行距60 cm×双株三角留苗,③宽窄行距(宽行70 cm + 窄行距50 cm)×单株留苗和 ④宽窄行距×双株三角留苗共12种方式进行处理,测定光合及叶绿素荧光参数。研究不同群体结构对夏玉米灌浆期群体光合特性的影响。结果表明,在吐丝期,随着种植密度的增加,群体光合速率提高;蜡熟期以90000株/hm²最高,种植方式上表现为宽窄行大于等行距种植,双株留苗种植方式大于单株种植方式,差异均达到显著水平;随着种植密度的提高,群体内3个层次叶片最大光能转换效率(Fv/Fm)、光化学猝灭系数(qP)逐渐降低,种植方式基本表现为宽窄行大于等行距,留苗方式表现为双株大于单株。试验条件下,以90000株/hm²,宽窄行,双株三角留苗产量最高。

Photosyntheticcharacterization and yield of summer corn (Zea mays L.) during grain filling stage under different planting pattern and population densities

Population structure is one of the important factors affecting photosynthetic efficiency and yield formation of crop plants. A 3 x 4 factorial field experiment with maize (Zea mays L.) was arranged in a split plot design with 4 replications. Three population densities (75000, 90000, 105000 plants/hm²) were assigned in the main plots, each of which was divided into four subplots to host the planting patterns: 1) even plant spacing in a conventional 60 cm row, 2) double plants in a triangle arrangement in the same 60cm row spacing, 3) even plant spacing in a twin-row arrangement with 50 cm within each twin-row and 70 cm row spacing between two twin-rows, and 4) similar to 3), but with double plants in a triangle arrangement within each row in the twin-row arrangement. During the grain filling period, photosynthesis and chlorophyll fluorescence parameters were measured. The results showed that under the high plant density, canopy apparent photosynthesis of double-plant planting pattern in the twin-row treatment was higher (P < 0.05) than that of the even plant spacing in the conventional 60 cm row spacing. With increasing plant densities, the values of Fv/Fm, and qP were all reduced slightly to significantly, there were larger reductions in the chlorophyll florescence parameters in twin-row than in single row planting patterns, and in double-plant planting pattern than in the equal-distance single row plant spacing. The 90000 plants/hm² density in double-plant planting pattern and twin-row spacing arrangement had the greatest canopy photosynthetic productivity and greater yield.