不同施磷水平对冷浸田水稻磷含量、光合特性及产量的影响

为探讨施磷对冷浸田水稻(Oryza sativa)生长的作用,研究不同施磷水平对水稻植株的磷含量、光合特性及产量的影响。结果表明,与对照相比,分蘖期增施磷肥使根、茎叶的磷含量和叶片净光合速率增加10.53%~36.84%、18.52%~37.03%和15.17%~29.88%;抽穗期使根、茎叶和稻穗的磷含量增加11.76%~23.53%、24.13%~41.38%和9.68%~22.58%,叶片净光合速率和可溶性糖含量提高13.41%~27.10%和6.03%~22.38%,而淀粉含量则降低12.05%~41.77%;成熟期的稻穗磷含量和产量增加0.71%~28.57%和4.65%~10.32%。施磷量(X)与稻谷产量(Y)满足方程:Y=-0.0835X~2+14.224X+6530.9(r=0.94*),抽穗期茎叶磷含量、叶片净光合速率与稻谷产量的相关系数分别为0.57*和0.77*。因此,冷浸田增施磷肥可提高水稻植株的磷含量、叶片净光合速率和可溶性糖含量,并降低叶片淀粉累积,从而提高稻谷产量。抽穗期是磷肥影响冷浸田水稻产量的关键时期,0.38%的茎叶磷含量可作为磷素养分丰缺的诊断指标,冷浸田水稻磷肥(P2O5)的推荐用量为85.17 kg hm–2。

Effects of Phosphorus Fertilizer on Phosphorus Content, Photosynthesis Characters and Yield of Rice in Cold Waterlogged Paddy Field

In order to understand the effect of phosphorus fertilizer on rice (Oryza sativa) grown in cold waterlogged paddy field, the phosphorus content, photosynthesis characters and yield were studied under four levels of phosphorus fertilizer. The results showed that the phosphorus contents in roots, stems and leaves, net photosynthetic rate of leaves treated with phosphorus fertilizer at tillering stage were higher than those of control by 10.53%-36.84%, 18.52%-37.03% and 15.17%-29.88%, respectively. At heading stage, the phosphorus contents in roots, stems and leaves, and panicles, net photosynthetic rate and soluble sugar content of leaves increased by 11.76%-23.53%, 24.13%-41.38%, 9.68%-22.58%, 13.41%-27.10% and 6.03%-22.38%, respectively, but the starch content reduced by 12.05%-41.77%. At mature stage, the phosphorus content of panicles and yield increased for 0.71%-28.57% and 4.65%-10.32%. There was regression equation between phosphorus fertilizer dosage (X) and rice yield (Y): Y=-0.0835X²+14.224X+6530.9 (r=0.94^*). The coefficients between rice yield and net photosynthetic of leaf, phosphorus content of stems and leaves at heading stage were 0.57^* and 0.77^*, respectively. Therefore, phosphorus fertilizer could improve phosphorus content of rice, net photosynthetic and soluble sugar content in leaves, reduce starch accumulation in leaves, thus improve rice yield. Heading stage was an important period for rice yield. It could be used as diagnostic reference index that the phosphorus content in stems and leaves was about 0.38%. The optimal dosage of phosphorus fertilizer is 85.17 kg hm^-2 for cold-waterlogged paddy field.