不同施磷量对小麦旗叶光合性能和产量性状的影响

为揭示磷肥调控光合作用的可能机制,1999～2001年度在河北农业大学教学基地进行了不同施磷水平的田间试验。供试品种为河农859,设3个磷肥水平(分别为P2O575,225和375.kg/hm2)。结果表明,在施用P2O575～375.kg/hm2的范围内,随施磷量增加,旗叶净光合速率(Pn)、气孔导度(Gs)、叶绿素含量(Chl)、可溶性蛋白质含量(Pro)和ATP酶活性都增加,叶绿素含量缓降期(RSP)和光合速率高值持续期(PAD)延长,而胞间CO2浓度(Ci)随施磷量的变化并不规律。高施磷量(P2O5375.kg/hm2)时,旗叶的叶绿素b含量(Chlb)减少、希尔反应和非环式光合磷酸化活性受到抑制,对磷肥的响应规律基本一致。但此条件下,Pn并不低,产量构成因素和子粒产量也最高。表明,尽管以上三个指标对磷肥响应敏感,但在一定范围内波动并不影响碳固定能力,不致成为光合作用的主要限制因素。

Effects of phosphorus fertilization on flag leaves photosynthesis and yield components in wheat

Many reports have dealt with the effects of phosphorus deficiency on photosynthesis,but few researches(focused) on the effects of P under normal and excessive condition on the crop photosynthesis and yield components.In order to clarify the possible mechanism of phosphorus nutrition on various aspects of photosynthetic metabolism and yield characters,and to provide the scientific support for phosphorus fertilization recommendation,a field experiment was conducted on the Teaching and Demonstration Farm of Agricultural University of Hebei during 1999—2001 with a winter wheat(Triticum aestivum L.) cultivar Henong 859 as the test crop.The three phosphorus fertilization levels selected were P₂O₅ 75,225 and 375(kg/ha).The results showed that,within the scope of in vitro phosphorus fertilization(75—375(kg/ha),) the P_n,Gs,Chl,Pro and ATPase activities were increased,the RSP and PAD were prolonged,but the intercellular CO₂ concentration(Ci) changed irregularly with increasing of phosphorus application rates.Under high phosphorus level(375 kg/ha),Chlb content,Hill reaction and non-cycle photophosphorylation activities of flag leaves were retarded,and these parameters showed a similar regularity change indicating they were more sensitive to phosphorus than the other parameters determined.The Pn of flag leaves,however,was still quite high under the high phosphorus level(375 kg/ha),resulting in the highest yield components and grain yield.We concluded that in spite of the high response sensitivity of Chl b content,Hill reaction and non-cycle photophosphorylation activities to P,they slightly affected carbon assimilatory within the certain range and should not be considered as the major limiting factors of photosynthesis.