不同时期超级杂交稻光合特性及氮素利用效率研究

Study on Photosynthetic Characteristics and Nitrogen Utilization Efficiency of Super Hybrid Rice in Different Periods

为探明不同时期超级杂交稻光合特性及氮素利用效率的差异,以5个不同时期具有代表性的超级杂交稻品种为试验材料,研究其光合特性、氮素利用率及氮素光合效率的变化特点。结果表明,前3期超级杂交稻产量随着施氮量的增加呈先升高后降低的趋势,均在施氮量为300 kg·hm-2水平时最高;后2期超级杂交稻产量随着施氮量的增加而增加,但施氮量为390 kg·hm-2与300 kg·hm-2的产量差异不显著。随着施氮量的增加,各时期超级杂交稻净光合速率(Pn)、比叶重(SLW)、氮素吸收利用率(REN)均呈先增加后降低的趋势,氮素光合利用效率(PNUE)和氮素偏生产力(PEPN)呈逐渐降低趋势;在各时期超级杂交稻品种中,随着品种的演进,其叶片氮含量(LNC)和SLW均得到显著改善,而光合生理特性和PNUE则无明显的变化。综上所述,在超级杂交稻品种改良中对氮素吸收利用的提高幅度大于较光合利用明显,在今后超级杂交稻品种改良中应着重对叶片光合生理特性方面的提高。本研究结果为超级杂交稻的选育提供了理论依据。

To explore the differences of photosynthetic characteristics and nitrogen utilization efficiency of super hybrid rice in different periods, the photosynthetic characteristics, nitrogen utilization ratio and nitrogen photosynthetic efficiency of 5 representative super hybrid rice varieties in different periods were studied. The results show that the yield of the first three stage super hybrid rice increased first and then decreased with the increase of fertilizer application,the yield is the highest at 300 kg·hm-2 nitrogen application,and the yield of the second stage super hybrid rice increased with the increase of fertilizer application,but there was no significant difference between the yield of 390 kg·hm-2 and300 kg·hm-2. With the increase of nitrogen application,the net photosynthetic rate( Pn),specific leaf weight and nitrogen uptake rate( REN) of super hybrid rice were increased first and then decreased,and the photosynthetic nitrogen use efficiency( PNUE) and nitrogen partial productivity( PEPN) were decreased gradually. In the super hybrid rice varieties of different periods,leaf nitrogen content and leaf weight were improved remarkably with the evolution of the varieties, but there was no significant change in photosynthetic physiological characteristics and nitrogen photosynthetic efficiency. In summary,the improvement of nitrogen uptake and utilization was greater than that of photosynthetic utilization in super hybrid rice,so the improvement of leaf photosynthetic physiology should be increased in super hybrid rice in the future. The results of this study provides a theoretical basis for the breeding of super hybrid rice.