【作者】 张敏；

【导师】 盛建东； 冯固；

【作者基本信息】 新疆农业大学 ， 土壤学， 2016， 硕士

【摘要】 提高植物磷效率的有效途径之一是充分挖掘植物高效吸收利用土壤磷的生物学潜力。农田土壤中存在大量的土著丛枝菌根(AM)真菌,作物不可避免地要被这些AM真菌所侵染。因此,菌根作物吸收磷实际上是由根系途径和菌根途径共同完成。本论文采用营养液和盆栽的方法,在温室条件下首先比较了棉花磷效率,然后通过5个土壤供磷强度的试验确定AM真菌对菌根和非菌根棉花生长和磷吸收效率最大的土壤适宜供磷强度,最后又进一步设置低磷、适宜供磷和高磷3种条件下比较了1950s-2010s不同年代培育的棉花品种的菌根响应度的差异。得出的主要结果如下:(1)棉花磷吸收效率和利用效率都存在显著的基因型差异。在营养液培养条件下新陆早13号和19号两个棉花基因型的生物量和总根长对供磷强度的响应仅在不供磷与供磷条件下有显著差异,而两个基因型仅在不供磷条件下,新陆早13号在各个供磷强度的根系磷吸收效率均高于新陆早19号。土培条件下,随土壤供磷强度增加棉花生物量和根系生长均显著增加。低磷条件下(Olsen-P为6-18mg·kg-1),新陆早19号的生物量和根长显著高于新陆早13号;高磷条件下(Olsen-P为46-73mg·kg-1),两品种之间的差异没有达到显著水平。这进一步说明所选用的棉花基因型磷效率差异主要表现在对低磷胁迫的响应,新陆早19号属于低磷高效的基因型和新陆早13号属于低磷低效基因型。(2)棉花的根系形态特征参数(根系长度和根系体积)对供磷强度的响应不敏感。在营养液培养条件下,根系形态对供磷强度的响应不敏感,仅在不供磷与供磷条件下存在显著差异;供磷强度达到50μmol·L-1后随着供磷强度增加,棉花根系长度不再增加。土培条件下,土壤供磷强度为46-73mg·kg-1时棉花的总根长显著高于供磷强度为6-18mg·kg-1条件下的根长,土壤供磷强度在6-18mg·kg-1条件下的总根长没有显著差异;在土壤供磷强度为9-73mg·kg-1时,新陆早19号的总根长显著高于新陆早13号。这进一步证实新陆早19号属于磷高效基因型。(3)棉花根系生理特征参数(分泌磷酸酶活性和质子与有机酸的数量)对供磷强度的响应的敏感程度不同的指标表现不一。在营养液培养和土培两种不同生长条件下,随供磷强度的增加根表磷酸酶显著下降,在各个供磷强度下品种间的磷酸酶活性均没有显著差异。营养液培养条件下,营养液实际p H(pH6.2)条件下的酸性磷酸酶比pH5.2大的多;而土培条件下,土壤实际p H(pH8.2)条件下的磷酸酶比pH5.2的酸性磷酸酶小很多。说明棉花根系表面的磷酸酶活性受pH的变化较大,在p H6.2时最高;磷酸酶活性在pH5.2和pH8.2两种条件下的变化是同步的。评价根表或根际土壤磷酸酶活性,应以环境实际pH值作为测量条件。(4)棉花生长对AM真菌的响应受土壤供磷强度的强烈影响。低磷(6-9mg·kg-1)条件下,两个棉花品种的生物量、磷吸收量、根长和根际碱性磷酸酶受AM真菌的影响较小;中度供磷(18mg·kg-1)条件下,AM真菌对棉花生物量、磷吸收量、根长和根际碱性磷酸酶的影响达到最大值;高磷(48-73mg·kg-1)条件下,AM真菌对棉花生物量、磷吸收量、根长和根际碱性磷酸酶的影响减弱,甚至出现负效应。菌根侵染率与棉花生物量菌根响应度和磷吸收菌根响应度均呈显著正相关关系,说明菌根侵染率可以作为棉花菌根响应度的筛选指标。(5)不同年代培育的棉花品种的菌根响应度存在差异。不同年代培育的棉花品种生物量的菌根响应度表现出二种类型:一种是在低、中、高三种供磷强度下均表现出正菌根效应(比如苏K202号、军棉一号、新陆早2号、新陆早13号和新陆中54号)。另一种是在低磷和适磷条件下表现出正菌根效应,而在高磷条件下则表现出负菌根效应(比如新陆早1号、新陆中21号和新陆早57号)。对磷吸收效率相关性状进行主成分分析,结果表明,较低磷条件下第一主成分(48%)以菌根性状为主,第二主成分(21%)以菌根性状和根系性状为主;高磷条件下第一主成分(31%)以根系性状为主,第二主成分(23%)以菌根性状为主。通过上述结果可以获得如下结论:新陆早13号和新陆早19号在土壤和营养液两种生长介质中根系形态存在差异,不同供磷强度下棉花的根系形态和磷酸酶活性能出现可塑性变化。适宜土壤供磷强度条件下,棉花生长和磷吸收对AM真菌的响应最大。不同年代培育的棉花品种菌根响应度存在差异。更多还原

【Abstract】 Exploiting crop biological genetic potential is an effective way to improve the efficiency of phosphorus crop.Arbuscular mycorrhizal fungi(AMF) are ubiquitous in agricultural ecosystems and then crops live in association with AMF. So in an AM plant, P can be absorbed through both the root and mycorrhizal uptake pathways. In this paper, the screening of cotton phosphate efficiency, and through five phosphorus supply to confirm optimal-P supply, with the effect of AM fungi on the growth and phosphorus uptake of cotton, and set low-P, medium-P, high-P to study the differences in mycorrhizal responsiveness of cotton cultivars bred in different years. The main conclusions are as follows:(1)There were significant differences in P uptake efficiency and utilization efficiency of cotton.Under nutrient solution culture Xinluzao13 and Xinluzao19 biomass and root length had significant difference only under the conditions between of no phosphorus and of phosphorus supply, and two genotypes the root phosphorus uptake efficiency of Xinluzao13 was higher than that of Xinluzao19 only under no phosphorus supply. Under soil culture cotton biomass and root length significant increased with the increased of phosphorus supply. Xinluzao19 significantly higher than Xinluzao13 under low-P supply(Olsen-P was 6-18mg·kg-1), cotton cultivars had no significant difference under high-P supply(Olsen-P was46-73mg·kg-1). This further illustrates the difference of genotype phosphorus efficiency in cotton was mainly in response to low phosphorus stress, Xinluzao19 belong to low P high phosphorus efficiency genotype and Xinluzao13 belong to low P low phosphorus efficiency genotype.(2)Response of morphological characteristics of cotton root parameters(root length and root volume)to phosphorus supply was not sensitive.Under nutrient solution culture the response of root morphology to phosphorus supply was not sensitive, there was a significant difference only under the conditions between of no phosphorus and of phosphorus supply. When phosphorus supply was higher than 50μmol·L-1, the increase of phosphorus supply will not improve root length anymore. Under soil culture when phosphorus supply was 46-73mg·kg-1 the root length significantly higher than phosphorus supply was 6-18mg·kg-1,when phosphorus supply was 6-18mg·kg-1 was not significantly difference; when phosphorus supply was9-73 mg·kg-1, the root length of Xinluzao19 was higher than that of Xinluzao19. This further illustrates Xinluzao19 belong to high phosphorus efficiency genotype.(3)Response of physiological characteristics of cotton root parameters(the secretion of phosphatase activity and secretion of protons and the number of organic acids) to phosphorus supply depend on different indicators. Under the nutrient solution culture and soil culture the activity of phosphatase on cotton root surface decreased sharply with the increase of phosphorus supply, and the phosphatase activity of two cotton cultivars had no significant difference under all phosphorus supply. Under nutrient solution culture the activity of acid phosphatase at actual pH(pH=6.2) was higher than pH5.2, but under soil culture the phosphatase at soil actual pH(pH=8.2) was lower than the acid phosphatase at pH5.2. This indicated thatcotton root surface phosphatase activity change with pH, maxmium with pH=6.2. Phosphatase activity in pH 5.2 and pH8.2 under two conditions of change was synchronous. Evaluate root surface or rhizosphere soil the phosphatase activity, the environment actual pH should be used as the measuring condition.(4)Effects of AM fungi on the growth of cotton were controlled by soil phosphorus supply. Two cotton cultivars of biomass 、 P content、root length and rhizosphere alkaline phosphatase activity less affected by AM fungi under low-P(6-9mg·kg-1); the effect of AM fungi on cotton of biomass、P content、root length and rhizosphere alkaline phosphatase activity reached the maximum under medium-P(18mg·kg-1); the effect of AM fungi on cotton of biomass、P content、root length and rhizosphere alkaline phosphatase activity weakened, even negative effects under high-P(48-73mg·kg-1). Mycorrhizal was positively correlated with cotton mycorrhizal biomass responsiveness and mycorrhizal phosphorus uptake responsiveness. This indicated that mycorrhizal colonization can be used as a screening index on cotton mycorrhizal responsiveness.(5)Old and recently released cultivars differed in their response to AMF. Two kinds of responses(in terms of shoot growth) were observed: the positive response in low-P(Olsen-P)、medium-P and high-P trearment(i.e. cultivars SK202、JM1、XLZ2、XLZ13 and ZM54); the positive response in low-P and medium-P or the negative response in high-P soil(i.e. cultivars XLZ1 、 ZM21 and XLZ57). Principal component analysis of the correlation of phosphorus uptake efficiency showed that, in the low-P soil the first PC(48%) comprised mycorrhizal traits, and the second PC(21%) comprised mycorrhizal and root traits,while in the high-P soil the first PC(31%) comprised root traits, and the second PC(23%) comprised mycorrhizal traits.The following conclusions can be obtained by the above results: Under the nutrient solution culture and soil culture root morphology was different on P efficiency of Xinluzao13 and Xinluzao19. There is a plasticity change between root morphology and phosphatase activity under different phosphorus supply.The effect of AM fungi on the growth and phosphorus uptake of cotton was maximum under optimal-P supply. There was difference in mycorrhizal response of cotton cultivars bred in different years.更多还原