不同大豆品种幼苗对低磷胁迫的生理响应及综合评价

Physiological responses of different varieties of soybean to low phosphorus stress and comprehensive evaluation

【目的】研究不同大豆品种幼苗对低磷胁迫的响应,为耐低磷大豆的筛选和育种改良提供理论依据。【方法】以13个大豆品种[黔豆11号(Qd11)、商豆1013(Sd)、牛毛黄豆(Nm)、中黄13号(Zh13)、七星1号(Qx1)、华春6号(Hc6)、中黄30(Zh30)、华夏3号(Hx3)、矮选(Ax)、华夏2号(Hx2)、绥阳豆(Sy)、中黄301(Zh301)和中黄61(Zh61)]为试验材料,设正常供磷(0.5 mmol/L KH_(2)PO_(4))和低磷胁迫(0.02 mmol/L KH_(2)PO_(4))2个磷处理,进行沙培试验,研究低磷胁迫下不同大豆品种幼苗的生长形态和生理特性,并通过隶属函数法综合评价不同大豆品种的耐低磷能力。【结果】低磷胁迫下,大豆的株高、茎粗、叶面积、地上部干重和磷含量有降低趋势,而根冠比和地上部磷利用效率有上升趋势;低磷胁迫也对大豆叶片的SPAD值和荧光参数产生影响,SPAD值、最大荧光产量(F_(m))、可变荧光(F_(v))、PSⅡ潜在活性(F_(v)/F_(o))、PSⅡ最大光化学效率(F_(v)/F_(m))多为降低趋势,而初始荧光(F_(o))多为升高趋势;此外,低磷胁迫下大豆叶片丙二醛(MDA)含量及超氧化物歧化酶(SOD)和过氧化物酶(POD)活性有上升趋势。基于耐低磷能力综合值(D),可将13个大豆品种分为耐低磷型、中间型和低磷敏感型,其中耐低磷型品种(Qx1、Sy和Hx2)整体表现为生理调节能力较强,有较高的地上部磷利用效率,能通过提高抗氧化酶活性降低叶片损伤,维持正常光系统途径;中间型品种(Ax、Zh30、Hc6和Qd11)叶片膜损伤较低,但光系统受损较大;低磷敏感类型大豆品种(Zh301、Hx3、Zh61、Zh13、Sd和Nm)地上部磷利用效率降低,生理调节能力较弱,叶片功能受损严重。【结论】不同大豆品种对低磷胁迫的响应程度存在差异,参试材料中Qx1、Sy和Hx2的耐低磷能力相对较强,能更好适应低磷环境来保证正常的生长发育和生理活动。

【Objective】To investigate how seedlings of various soybean varieties reacted to low phosphorus stress and to offer a theoretical reference for selecting and breeding more low phosphorus tolerant soybeans.【Method】Thirteen soy‐bean varieties Qiandou 11(Qd11),Shangdou 1013(Sd),Niumao soybean(Nm),Zhonghuang 13(Zh13),Qixing 1(Qx1),Huachun 6(Hc6),Zhonghuang 30(Zh30),Huaxia 3(Hx3),Aixuan(Ax),Huaxia 2(Hx2),Suiyangdou(Sy),Zhonghuang 301(Zh301),and Zhonghuang 61(Zh61)were used as test materials.Two phosphorus treatments were set up:0.5 mmol/L KH_(2)PO_(4) for normal phosphorus supply and 0.02 mmol/L KH_(2)PO_(4) for low phosphorus stress.The effects of low phosphorus stress on the growth morphology and physiological characteristics of soybean seedlings were in‐vestigated through the sand cultivation test.The ability of different soybean varieties to tolerate low phosphorus was comprehensively evaluated by the membership function method.【Result】While the root-shoot ratio and aboveground phospho‐rus use efficiency tended to rise,soybean plant height,stem diameter,leaf area,aboveground dry weight,and phospho‐rus content tended to decrease under low phosphorus stress.The SPAD values and fluorescence parameters of soybean leaves were also impacted by low phosphorus stress;there were primarily increasing trends in initial fluorescence(F_(o))and decreasing trends in maximum fluorescence yield(F_(m)),variable fluorescence(F_(v)),potential PS II activity(F_(v)/F_(o)),and maximum photochemical efficiency of PSII(F_(v)/F_(m)).Additionally,low phosphorus stress led to a tendency of decreasing the malonaldehyde(MDA)content of soybean leaves,while superoxide dismutase(SOD)and peroxidase(POD)ac‐tivities exhibited an increasing trend.The thirteen soybean varieties could be divided into three categories based on capac‐ity comprehensive value(D)of the comprehensive evaluation of low phosphorus tolerance:low phosphorus tolerant type,intermediate type,and low phosphorus sensitive type.Low phosphorus tolerant varieties(Qx1,Sy and Hx2)dem‐onstrated greater physiological regulation overall,higher aboveground phosphorus utilization efficiency,and the ability to maintain normal photosystem pathways by increasing the activity of antioxidant enzymes to reduce leaf damage;inter‐mediate varieties(Ax,Zh30,Hc6 and Qd11)had lower leaf membrane damage but greater photosystem damage;low phosphorus sensitive soybean varieties(Zh301,Hx3,Zh61,Zh13,Sd and Nm)had reduced aboveground phosphorus utilization efficiency and weak physiological regulation ability,their leaf functions were severely damaged.【Conclusion】Different soybean varieties varied in their response to low phosphorus stress.Among the materials used,Qx1,Sy and Hx2 are comparatively more tolerant of low phosphorus and better suited to low phosphorus environments to ensure nor‐mal growth,development and physiological activities.