摘要:为探明果粮间作模式下树冠遮阴对间作冬小麦灌浆期光合特性和产量的影响，为新疆南疆果粮间作模式的选择和优化提供理论依据，本研究以扁桃-冬小麦间作模式为研究对象，设置重度遮阴和轻度遮阴2个处理，以单作小麦为对照，对间作区域光合有效辐射（PAR）、小麦产量及灌浆期叶片光合色素和可溶性蛋白含量、光响应曲线、荧光动力学参数、群体光合速率进行测定。结果表明：间作区域遮阴程度受树冠结构和间作区域距树体距离共同影响，主干分层形扁桃（重度遮阴）近冠和远冠间作区域小麦灌浆期PAR日均值为自然光强的18.61%和25.90%，小冠圆头形扁桃（轻度遮阴）对应值为56.00%和64.53%。与扁桃间作导致小麦旗叶Chla+b含量和Chla/b比值降低；PAR日均值≤56.00%自然光时，小麦旗叶可溶性蛋白质含量显著降低；PAR日均值≤25.90%自然光时，旗叶光系统Ⅱ的实际光合效率（ΦSPⅡ）、光化学淬灭系数（qP）、最大净光合速率（Pmax）及群体光合速率日均值均显著降低；PAR日均值≥64.53%自然光时小麦群体光合速率存在明显的补偿现象。综上，扁桃-冬小麦间作模式下，小麦光合能力及产量与遮阴程度密切相关，重度遮阴导致小麦单叶和群体光合能力及产量显著降低；轻度遮阴条件下，小麦旗叶光合能力无显著变化，群体光合速率存在明显的补偿现象，对产量无显著影响。
关键词:扁桃-冬小麦间作/
树形/
遮阴强度/
间作区域/
光合特性/
产量
Abstract:Fruit tree-wheat intercropping is practiced in large parts of southern Xinjiang, a region where agroforestry intercropping is the main type of agricultural production. In the present study, a field experiment was conducted to investigate the effects of the shading degree from fruit tree canopies on the grain yield and photosynthetic characteristics of wheat at the grain filling stage. This study aimed to provide information for the selection of management standards and the optimization of the intercropping system in southern Xinjiang. In the experiment, 'Xindong 20' (Triticum aestivum L. var. Xindong 20), the main winter wheat cultivar in South Xinjiang, was used as the research object, and two treatments (heavy and light shading) were established by cutting the almond (Amygdalus communis L.) canopy of the almond-winter wheat intercropping system; delayed open-central canopy (DC) and a semicircle small-canopy (SC), respectively. Monocultured wheat was used as the control. The yield and yield components, photosynthetic pigments and soluble protein contents, light response curves, chlorophyll fluorescence induction of the flag leaves, and the canopy apparent photosynthetic rate of the intercropped wheat were investigated in three areas: near the canopy west of the almond trees, near the canopy east of the almond trees, and far from the canopy. The results indicated that the shading degree of the tree canopy was closely associated with the canopy size and the distance between the intercropping area and the tree. The daily mean values of photosynthetically active radiation (PAR) in the intercropping areas near and far from the almond canopy were 18.61% and 25.90% with DC, and 56.00% and 64.53% with SC of the natural light intensity during the wheat-filling period, respectively. The content of Chla+b and the Chla/b ratio in the wheat flag leaves were reduced in both shading treatments. When the daily mean strength of PAR was ≤56.00% of the natural light intensity, the soluble protein content in the wheat flag leaves was significantly reduced. When the daily average intensity of PAR was reduced to 25.90% and 18.61% of the natural light, the indices of optical system Ⅱ actual photosynthetic efficiency (ΦSPⅡ), photochemical quenching coefficient (qP), and maximum net photosynthetic rate (Pmax) of the flag leaves, as well as the daily mean canopy photosynthetic rate (CAP) value, were significantly reduced. Under the light shading intercropping condition, when the daily mean intensity of PAR reached ≥ 64.53% of the natural light intensity, the CAP value exhibited an obvious increased (compensation phenomenon). In the almond-winter wheat intercropping system, the influence of a weak light environment caused by the tree canopy on wheat photosynthetic capacity and yield was closely related to the degree of shading. Heavy shading resulted in a significant decrease in single-leaf Pn and CAP and caused a significant decrease in yield. Under light shading conditions, the photosynthetic capacity of wheat flag leaves did not change, while CAP had a significant compensation phenomenon and no significant influence on grain yield.
Key words:Almond-winter wheat crop intercropping/
Tree form/
Shading degree/
Intercropping area/
Photosynthetic characteristics/
Grain yield
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