【作者】 吴亚维；

【导师】 马锋旺；

【作者基本信息】 西北农林科技大学 ， 果树学， 2008， 硕士

【摘要】 土壤紧实度是衡量土壤紧实程度的指标,它与土壤其他特性如土壤容重直接相关,土壤紧实、容重偏高是我国当前果树生产中普遍存在的逆境胁迫因子之一。本试验研究了不同土壤紧实度对苹果(Malus pumila. Mill)植株生长发育以及土壤微生物和土壤酶活性的影响,旨在丰富果树逆境生理理论,并为果树土壤改良提供理论依据。采用盆栽试验,研究了不同土壤紧实度对苹果幼苗生长、生物产量、叶绿素荧光参数、根系生长以及根系活力的影响;采用大田试验,研究了平邑甜茶(Malus hupehensis . Rehd)和新疆野苹果(Malus sieversii. Roem)两种不同砧木的嘎拉苹果,经不同容重土壤处理2年后植株生长特性与生物产量的差异;初步研究了土壤紧实度与水分胁迫对苹果幼苗生长的互作效应;为了进一步了解土壤紧实胁迫影响苹果正常生长的原因,对不同容重的土壤中土壤微生物数量和土壤酶活性的差异进行了初步探索。紧实土壤条件下平邑甜茶、楸子(Malus prunifolia. Borkh)以及嘎拉苹果植株的生长指标及生物产量均发生不同程度的下降;通过对平邑甜茶叶片叶绿素荧光参数的分析发现,1.55 g·cm-3处理的植株叶片内部光能转化机构功能下降,紧实土壤中平邑甜茶叶片组织中O2.-和H2O2含量的显著升高在一定程度上诱导了抗氧化酶活性的提高,但是植物体内活性氧(reactive oxygen species ,ROS)增幅更大,从而使细胞膜受到伤害,透性增大,发生膜脂过氧化,最终表现为叶片相对电导率(relative electrical conductivity,REC)和丙二醛(MDA)含量显著升高。通过不同时期对根系形态的观察看出,过于紧实土壤(1.55 g·cm-3)中生长的楸子根系生长减慢、根系数量减少、根系活力下降,1.25和1.40 g·cm-3两个处理间差异不显著。在持续干旱的情况下,一定紧实程度的土壤有利于保持土壤水分,楸子幼苗受到干旱胁迫伤害小。不同砧木的苹果植株生长受土壤紧实度影响的幅度有差异。土壤微生物数量和土壤酶活性也会受到土壤紧实度的变化的影响,适度紧实的土壤有利于土壤微生物数量尤其是细菌数量的增加,脲酶和脱氢酶活性随着土壤紧实度的增加而下降,碱性磷酸酶和转化酶在1.40 g·cm-3容重土壤中最高,过氧化氢酶随着土壤紧实度的增加而增加。总之,紧实土壤不利于苹果的生长以及生物产量的增加,然而在持续干旱的情况下紧实土壤比疏松土壤保水。土壤紧实度发生变化时,苹果植株形态和生理生化功能以及土壤的容重、土壤微生物和土壤酶土壤都会产生出适应性响应与调整。更多还原

【Abstract】 Soil compaction is an indicator measuring the degree of soil compaction,and it has a direct relationship to other properties such as soil bulk dentisity.Soil compaction, high density is one of stress factors which is prevalent in China’s current production of fruit trees.Effcets of different soil compaction on apple plant growth,soil microbial and soil enzymatic activities were studied in the experiment, aim to enrich pomology physiological theory of adverse circumstances and provide theoretical basis for soil improvement.Pot culture experiment was conducted to study the effects of soil compaction with different soil bulk dentisity(SBD,1.25 g·cm-3,1.40 g·cm-3and 1.55 g·cm-3) on apple tree growth, biological yield,chlorophyll fluorescence parameters,root growth and root activities of apple seedling.Though field experiments,difference of plant grow characteristic and biological yield of gala apple grafted on two rootstock(Malus hupehensis and Malus sieversii) growing under different SBD for two years were investigated.Interaction effects of soil compaction and water stress was researched preliminarily.In order to understand the reason that siol compaction affects apple growth, variation of microbiol number and soil enzymatic activities of different SBD were investigated preliminarily.Malus hupehensis ,Malus prunifolia and gala appale growth index and biological yield declineded at different degrees under soil compaction.Thougt the analyze of chlorophyll fluorescence parameters,we found out that conversion of light energy function of plant leaves dicreased under 1.55 g·cm-3SBD.The increase of Superoxide anion radical and Hydrogen peroxide content induced the rise activity of antioxidant enzymes,but the rise degree of reactive oxygen species (ROS) was bigger than the rise activity of antioxidant enzymes,so ROS did harm to cell membrane,which resulted in the increase of permeability of the membrane and lipid peroxidation, and which performanced in remarkable increasing of REC and MDA content of leaves.Through observation of root form and activity of Malus prunifolia seedling on different date,root of Malus prunifolia seedling under 1.55 g·cm-3SBD growed slowly,root number and activity decreased.The difference between 1.25 and 1.40 g·cm-3treatment were not significant. However, in the case of continuous drought, a certain extent soil compaction was conducive to soil moisture maintaining, injury of drought stress on plant was less than low soil bulk density.The impact of soil compaction on apple plant grafted different rootstock were different.Soil microbiol and soil enzymatic activities also were affected by the variation of soil compaction,Moderate compaction was favorable for soil microbiol number increase, especially for bacteria.With soil compaction increase,the activity of urease and dehydrogenase dropped, alkalescence phoshatase and invertase activity both were highest in 1.40 g·cm-3SBD, catalase enhanced with the soil compaction increasing.On the whole,soil compaction is not conducive to the growth of apple and the increase of biological yield.However, in the case of continuing drought compacted soil can maintain more water than loose soil. In the event of soil compaction change,apple plant morphology, physiological,biochemical functions,as well as the bulk density of soil,soil microbiol and soil enzymatic activities will produce adaptive response and adjustment.更多还原