【作者】 陈积山；

【导师】 常根柱； 李锦华；

【作者基本信息】 甘肃农业大学 ， 草业科学， 2008， 硕士

【摘要】 根系是植物与土壤相互作用的界面,其主要功能是吸收土壤中的水分和养分,而根系的构型对根系吸收水分和养分效率有重要影响。本研究针对根的多样性,初步探讨了幼龄苜蓿(Medicago sativa L.)在黄土高原半干旱区根系形态特征、农艺性状、根系构型划分及命名,并利用抗旱性指标分析不同根系构型的抗旱性。结果表明:1.品种间根系的主根长度和直径、一级侧根长度和直径、侧根数、根体积、根干重差异显著。在相同旱作条件下,苜蓿品种间侧根发生能力主要决定于品种的生物学特性,具有可遗传特性。2.根系形态指标间相关性分析表明,根干重分别与主根直径、侧根长度、侧根直径呈极显著正相关;侧根直径与侧根长度二者也呈极显著正相关。3.运用灰色系统关联度理论和模糊数学方法中的权重决策法对幼龄苜蓿根系形态与农艺性状指标分析。计算求得各个指标的权重系数为侧根长度>侧根数>生长高度>根夹角>主根直径>主根长度>侧根直径>根体积>生长速度>茎叶比。4.本研究通过探讨根系构型的划分及命名,确定根径比和根夹角为划分根系构型的典型指标,将轴根型苜蓿幼龄根系分为四类,即构型Ⅰ:细径小锐角型;构型Ⅱ:细径大锐角型;构型Ⅲ:粗径小锐角型;构型Ⅳ:粗径大锐角根型。5.通过抗旱性指标分析表明,可以将四类根系构型的抗旱性划分为强、弱两个抗旱能力类群。抗旱性强的根系构型为类型Ⅰ和类型Ⅲ,主要特点是含水量较大,膜透性较小,脯氨酸含量较大;抗旱性弱的根系构型为类型Ⅱ和类型Ⅳ,主要特点是含水量较小,膜透性较大,脯氨酸含量较小。6.根据根系构型的抗旱性强弱,可对属于不同根系构型的苜蓿品种的抗旱性作出推测。更多还原

【Abstract】 Root system is the medium between plant and soil,capturing water and nutrient from soil is the main function of the root,but root architectural features has important effects on the root’s ability to capture water and nutrient.Based on root,the text focus young alfalfa (Medicago sativa L.) on root morphology structure, agronomic traits, grouping and naming of root architectur, and using the indexes of drought resistance to analysis the capacity of drought resisitance of different root architectur in the arid and sim-arid regions of the Loess Plateau.The results show:1. There are distinctly difference among alfalfa cultivars in length and diameter of the main root, length and diameter of the max-secondary root, the number of the Lat.root, volume of root system and dry weight of root. Under same condition of dry farming, development ability of the max-secondary root mainly depend on plant of alfalfa cultivars, bearing a trait of inheritance.2.Based on correlation coefficient of root morphology indexes, dry weight of root is positively correlative with diameter of the main root,length and diameter of the max-secondary root, And length of the max-secondary is positively correlative with diameter of the max-secondary root.3. The root morphology and agronomic traits were evaluated using grey relevancy and decision making method of with information of Fuzzy Mathematics. The results showed that indexes of root morphology had the highest weight than of agronomic traits.4.Passing discussion partition and naming of root architectur, confirmation of root architectura must represent root morphplogy character and space character so that root indexes must be selected strictly. Lastly, root is confirmed as representative indexes for dividing root architectural, which will divide young Alfalfa root system to four groups,namly ArchitecturⅠ: thin diameter and small acute angle; ArchitecturⅡ: thin diameter and big acute angle; ArchitecturⅢ; thick diameter and small acute angle; ArchitecturⅣ: thick diameter and big acute angle.5. Using drought resistant indexes to analysis shows that the drought resistant capacity of root architectur will be divided two different drought resistant groups with strongness and feebleness. ArchitecturⅠand ArchitecturⅢare belong to the strong drought resistant group with the more containing water, the smaller relative permeability of cell memberance and the more content of free praline; ArchitecturⅡand ArchitecturⅣare belong to the feeble drought resistant group with the more containing water, the bigger relative permeability of cell memberance and the littler content of free praline.6. Based on different drought resistant capacity of root architectur, different drought resistant capacity of tested alfalfa cultivars belonged to different root Architectur will be conferred.更多还原