紫花苜蓿光合日进程及光合产物分配对施磷的响应  

Diurnal changes in photosynthesis and photosynthetic product partitioning in alfalfa in response to phosphorus application

作　　者：孙延亮 魏孔钦 刘选帅 赵俊威 李生仪 马春辉 张前兵[1] SUN Yan-liang;WEI Kong-qin;LIU Xuan-shuai;ZHAO Jun-wei;LI Sheng-yi;MA Chun-hui;ZHANG Qian-bing(College of Animal Science&Technology,Shihezi University,Shihezi 832003,China)

机构地区：[1]石河子大学动物科技学院,新疆石河子832003

出　　处：《草业学报》2022年第12期85-94,共10页Acta Prataculturae Sinica

基　　金：国家自然科学基金项目(32001400,32260347);霍英东青年教师基金(171099);兵团科技创新骨干人才计划项目(2021CB034);国家现代农业产业技术体系资助。

摘　　要：为探讨滴灌条件下紫花苜蓿光合日进程及光合产物分配对不同施磷水平的响应,明确苜蓿地上光合产物与叶片光合参数之间的关系,通过田间试验,设置0(CK)、50(P_(1))、100(P_(2))和150 kg·hm^(-2)(P_(3))4个施磷(P_(2)O_(5))水平,在紫花苜蓿初花期选择典型晴天(10:00-20:00),采用Li-6400便携式光合仪测定紫花苜蓿叶片光合指标及环境因子日进程,并对苜蓿植株叶、茎、根中的可溶性糖和淀粉含量进行测定。结果表明,不同施磷水平下紫花苜蓿均有光合“午休”现象,气孔限制是净光合速率(P_(n))下降的主要因素。光合有效辐射(PAR)对苜蓿叶片P_(n)影响最大,而大气CO_(2)浓度(C_(a))、大气温度(T_(a))、大气相对湿度(RH)和叶面饱和蒸气压亏缺(V_(pdl))对P_(n)的影响次之。主成分分析发现,苜蓿的光合效率由高到低依次是P_(2)>P_(1)>P_(3)>CK。当施磷水平为100 kg·hm^(-2)时,苜蓿的干草产量显著提高,紫花苜蓿叶片P_(n)、蒸腾速率(T_(r))和水分利用效率(WUE)的日进程均较对照有所提高,叶片胞间CO_(2)浓度(C_(i))日进程均较对照显著降低。叶、茎和根的可溶性糖含量分别提高了11.6%、5.0%和4.6%,淀粉含量分别提高了15.2%、9.6%和5.3%,可溶性糖和淀粉的资源分配更多地表现为对叶的分配增加,对茎和根相对较少。因此,适当施磷能提高紫花苜蓿叶片的光合效率,进而显著促进苜蓿的生长发育,施磷(P_(2)O_(5))量为100 kg·hm^(-2)时对紫花苜蓿光合的提升效果最为明显。This research explored the effect of different levels of phosphorus application on diurnal variation in photosynthesis and partitioning of photosynthetic products in alfalfa under drip irrigation.In particular,the relationship between photosynthetic product levels in the plant and leaf photosynthetic parameters of alfalfa was clarified.Four phosphorus(P_(2)O_(5))application levels of 0(CK),50(P_(1)),100(P_(2))and 150 kg·ha^(-1)(P_(3))were used as treatments in a field experiment.Leaf photosynthetic parameters were measured with a Li-6400 portable photosynthesis instrument on sunny days from 10:00-20:00 during the early flowering stage,together with environment factors and sugar and starch content in the leaves,stems and roots.A feature of the results was a‘photosynthetic noon-break’phenomenon across all phosphorus application treatments,and stomatal limitation was the main factor responsible for the mid-day decline of net photosynthetic rate(P_(n)).Photosynthetically active radiation had the greatest impact on the P_(n) of alfalfa leaves,while atmospheric CO_(2)concentration,atmospheric temperature,and atmospheric environmental factors such as relative humidity and vapor pressure deficit based on leaf temp also affected P_(n).Principal component analysis showed that alfalfa photosynthetic efficiency in the four P-treatments ranked P_(2)>P_(1)>P_(3)>CK.At the 100 kg·ha^(-1)phosphorus level(compared to CK),the hay yield of alfalfa was increased significantly,the soluble sugar contents of leaves,stems,and roots were increased by 11.6%,5.0%and 4.6%,respectively,and the starch contents were increased by 15.2%,9.6%and 5.3%,respectively.Higher overall levels of soluble sugar and starch typically manifested as greater concentration increases in leaves,and relatively smaller increases in roots and stems.The diurnal troughs in P_(n),transpiration rate,leaf internal CO_(2)concentration and water use efficiency(WUE)of alfalfa leaves were less marked in the P treatments,compared with the control treatment.Therefore,appr

关 键 词：施磷 紫花苜蓿 光合日进程 光合产物 

分 类 号：S541.9[农业科学—作物学]