玉米杂交种对缺磷反应的生理机制及基因型差异

【目的】揭示玉米杂交种对缺磷反应的生理机制,为高产高效品种的大面积推广应用提供科学依据。【方法】以蠡玉16、冀单28和宽诚10杂交玉米为供试作物,通过供磷和缺磷营养液培养研究缺磷对不同基因型玉米生长发育,根系形态、活性和生理特性的影响,并比较基因型间差异。【结果】与供磷比,缺磷的3个品种株高、地上部和整株干重及磷增长量均降低,根干重和根冠比均增加;根长依次增加61%、62%和18%,根半径降低19%、29%和4%,根表面积增加31%、18%和13%;总吸收面积和比表面积降低;pH降低1.3、0.8和0.7个单位;吸收H2PO4?和耐低磷能力提高;根组织中酸性磷酸酶活性提高。不同基因型间存在显著差异。【结论】缺磷时,蠡玉16干重增长最大,原因是其有较大的根长和根表面积,较活跃的根系吸收活性,较多的质子分泌,较强的耐低磷能力,较大的吸收速率和根内酸性磷酸酶活性。

Physiological Mechanism of Maize Hybrids in Response to P Deficiency and Differences Among Cultivars

[Objective]The objective of this study was to elucidate the physiological mechanisms of the maize hybrids under P deficiency condition,and to provide a scientific evidence for extension and utilization of cultivars with higher yield and efficiency.[Method]Three maize hybrids,Liyu 16,Jidan 28,and Kuancheng 10,were used as the testing materials and subjected to two phosphorus levels:sufficiency and deficiency.Effects of P deficiency on plant development,root morphology,activity and physiological characters were investigated among three cultivars at the seedling stage in hydroponic culture.[Result]The results showed that under P-deficiem condition,the height dry weight and P content increment in shoot and whole seedling all decreased while the dry weight of roots and ratio of root to shoot increased.Moreover,root length enhanced by 61%,62%,and 17%,root radius depressed by 19%,29%,and 4%,and root surface areaincreased by 31%,18%,and 13%,respectively,compared with plants with P.Total uptake area and specific surface areaof rootswere bothlow,and pH in the nutrient medium respectively reduced by 1.3,0.8,and 0.7 units,but the three cultivars all had higher uptake kinetics of H_2PO_4~- and stronger abilities to endure P deficiency.The acid phosphatase (APase)activities in root tissue were improved.However,there were still significant differences among the cultivars.[Conclusion]Comparedwith Jidan 28 and Kuancheng 10,Liyu 16 had higher dry weight increment,root length and root surface area,root activity and proton exudation,stronger tolerance ability to P deficiency,larger uptake kinetics of H_2PO_4~- and APase activity in root tissue.