中度盐碱地蓖麻生长和地上部干物质积累特性的研究

Growth characteristics and aboveground dry matter accumulation of castor plant grown on medium saline soil

以淄蓖5号和云蓖泰国202为试验品种,研究沿海滩涂中度盐碱地上种植密度和施氮量对蓖麻生长特性和地上部干物质积累的影响。结果表明:淄蓖5号和云蓖泰国202适宜的种植密度分别为13 000、16 000株·hm-2;2个品种适宜的施氮量均为120 kg·hm-2;氮肥在苗期和蕾期各施用50%时株高、真叶数和地上部干物重较为适宜,籽粒产量较高。灌浆成熟期地上部干物重和产量之间呈显著或极显著的正相关关系,开花期地上部干物质积累量与籽粒产量存在开口向下的一元二次方程关系,开花后的地上部干物质积累量与籽粒产量存在显著或极显著的正相关关系,表明提高开花后蓖麻植株的光合生产是提高蓖麻产量的关键。

Planting density and nitrogen application are two essential factors affecting growth characteristics and above ground dry matter accumulation of castor plants （Ricinus ccornmunis L）. A field experiment was conducted to investigate the effects of planting density and nitrogen application amount on growth characteristics and dry matter accumulation of Zibi 5 and Yunbi TCO 202 plants grown on medium saline soil. The suitable planting density for Zibi 5 and Yunbi TCO202 was 13 000 and 16 000 plant · hm-2, respectively. The suitable nitrogen application amount for both cultivars was 120 kg · hm-2. When the nitrogen fertilizer was applied equally at seedling stage and at budding stage, the plant height, leaf number and above ground dry matter accumulation of castor plants were maintained within reasonable ranges, and high castor bean yield was achieved. The dry weight of above-ground plant at grain filling and ripening stage and castor bean yield were positively correlated （P〈0.05 or P〈0.01）. The relationship between above ground dry matter accumulation during flowering stage and castor bean yield could be expressed with an inverted-U quadratic equation with one vari- able. The above-ground dry matter accumulation after flowering and castor bean yield were positively correlated （P〈0.05 or P〈0.01）. The key point of increasing castor bean yield is to enhance the photosynthetic production after the flowering stage.