【作者】 李岳峰；

【导师】 徐国华；

【作者基本信息】 南京农业大学 ， 植物营养， 2008， 博士

【摘要】 禾本科与豆科作物间作是在产量和资源利用率方面有着显著优势的一种广泛应用的种植模式,而且也是农业可持续发展方面的一项重要生产措施。水稻和绿豆都是热带和亚热带地区重要的粮食作物,水稻旱作不仅具有重要的节水意义,而且使得水稻和其他作物间作成为可能。在旱作水稻/绿豆间作系统中,绿豆生育期短,不仅可以早腾茬,而且由于其含氮量高,C/N比窄,残留在土壤中的绿豆根系将快速矿化分解,为水稻后期的生长提供养分。丛枝菌根真菌(AMF)是土壤中广泛分布的一类土壤微生物,几乎陆地植物的80%都可以与其共生形成丛枝茵根。丛枝菌根形成以后,能够促进宿主植物对土壤矿质元素的吸收,调节宿主植物的代谢,增强植物的抗逆性。因此,AMF繁殖体在现代可持续农业上可以作为土壤生物改良剂。然而,丛枝菌根在间作系统中的作用仍不清楚。本研究以旱作水稻和绿豆间作系统为研究对象,采用盆栽试验系统研究了不同AM真菌、不同供磷水平、不同分隔方式、不同水分状况等条件下,间作系统中菌根的形成、茵根对改善绿豆的固氮效率及旱作水稻和绿豆对氮吸收和转移的影响以及菌根对改善旱作水稻和绿豆磷素吸收的影响。主要研究结果如下：1.对旱作水稻／绿豆间作系统幼苗接种3种不同的丛枝菌根真菌[Glomus caledonium(Gc), Acaulospora laevis(Al),G. mosseae(Gm)],测定不同菌种对旱作水稻/绿豆间作系统根系的侵染状况,接种AMF后,水稻的菌根侵染率在12.5%-36.7%,绿豆的菌根侵染率在54.8%-66.7%。在三个不同的菌种中,尤以Gc的接种效果最佳。接种这三种不同AMF对间作系统作物接种的侵染以及建立共生体的能力不同,对作物生长发育的促进效应有明显差异。其中绿豆对Gm的依赖性最高,达47%。菌根侵染率对绿豆干重有显著的影响,菌根侵染率和绿豆作物地上部干物重和根系干物重都呈极显著正相关关系,相关系数分别为r=0.993和r=0.783。接种丛枝菌根真菌可显著增加水稻/绿豆间作系统作物对N、P的吸收,但这三种AMF对水稻和绿豆的可溶性糖和可溶性蛋白含量的影响无显著差异。2.选用G. caledonium菌种,研究了不同磷营养条件下丛枝菌根对水稻/绿豆间作系统中作物生长的影响。结果表明,土壤有效磷含量直接关系到丛枝菌根的形成和发育。接种AMF后,水稻中的P含量显著高于不接种处理；在10 mgP.kg-1水平下,水稻和绿豆对菌根菌的依赖性最高,这时水稻的侵染率也最高。在所有的磷水平下,接种AMF均显著提高水稻和绿豆的叶绿素含量,而且随着磷水平的提高,水稻和绿豆的磷含量、磷吸收量以及叶片叶绿素含量均随之增加。在旱作水稻/绿豆间作系统中,接种AMF对绿豆吸磷量的提高效果最佳,10 mgP.kg-1条件下,绿豆的吸磷量提高了98.34%。在不同施磷水平下,水稻和绿豆的根系活力和叶片可溶性糖量随磷水平的提高而增加。3.采用15N标记法,在旱作水稻/绿豆之间通过塑料网膜、尼龙网和无分隔三种种植方式研究菌根在旱作水稻和绿豆根间物质传递中的作用。结果表明,在AM形成的菌丝桥的作用下,水稻的总吸磷量提高了57%,绿豆的P和N的总吸收量分别提高了65%和64%,并且绿豆的根瘤量增加了54%。在无间隔条件下,当接种AMF时,绿豆向水稻的N转移率从5.4%提高到了15.7%,而且在根系不分隔或者用30 um尼龙网将两种作物的根系分隔但菌丝能穿过之间没有显著差异。我们发现无论接种或者不接种AMF从水稻到绿豆叶片的15N转移率仅2.7%。可以推断,禾本科与豆科植物间作能提高菌根侵染率,丛枝菌根的形成能显著增加水稻和绿豆对N、P的吸收、显著提高绿豆结瘤数以及绿豆向水稻的氮素转移。4.采用土培试验研究了不同土壤水分条件下接种AMF(G caledonium)对水稻/绿豆间作系统营养、生理代谢和抗旱性的影响。结果表明,水分胁迫严重抑制植株的生长,但对丛枝菌根的生长发育和侵染率影响不大。接种AMF不仅有利于植株对N、P的吸收,而且改善了植株的水分状况,增加可溶性糖累积,降低脯氨酸含量,减轻水分胁迫对植株生长的抑制。因此,菌根可以改善植株的水分状况,增加叶片相对含水量。5.研究了接种不同AMF对水稻/绿豆间作系统叶片抗氧化酶活性的影响。结果表明：接种AMF能提高作物体内的蛋白质含量,降低MDA的含量,增强叶片超氧化物岐化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)和多酚氧化酶(PPO)活性。抗氧化酶的活性与AMF对植株的侵染率有很好的相关性。表明接种AMF有利于增强水稻/绿豆间作系统中植株的抗逆性。总之,在水稻和绿豆间作系统中,AMF能显著提高水稻和绿豆的菌根侵染率和丛枝丰富度,提高抗氧化胁迫的能力以及氮、磷吸收和转移,该研究结果为在田间接种丛枝菌根真菌来发挥作物潜能、提高作物生产效率提供了一条新途径,为田间采用旱作水稻与绿豆间作的栽培措施,以达到节水、高产、环保和资源高效利用提供理论依据。更多还原

【Abstract】 Cereal-legume intercropping is a widely used agricultural practice with a significant advantage in yield increasing and in resource utilization, which has been considered as an important practice in the sustainable agriculture development. Rice(Oryza sative) and mungbean (Vigna radia ta L.) are important food crops in the world, especially in tropical and subtropical regions. Arbuscular mycorrhiza fungi (AMF) distribute widely in the environment, which are found in about 80% of the terrestrial plants. Significant roles of arbuscular mycorrhizal fungi have been obtained for the plant, for example, they can promote the absorption of phosphorus in roots, accelerate the growth of plants, protect the plant against disease. The fungi in return benefit from the supply of carbohydrates derived from plant leaf photosynthesis. Thus, propagula of AMF have been used as biological soil amendments in modern sustainable agriculture. However, the contribution of arbuscular mycorrhiza, the common existed mutualistic symbiosis between most of crop roots and mycorrhizal fungi, has not yet been fully understood in the intercropping system.To evaluate the contribution of AMF in rice and mungbean intercropping system, we inoculated AMF to intercropped rice and mungbean. By labeling 15N isotope, the interactions among AMF, rice and mungbean were conducted to test the hypothesis that AMF could improve the efficiency of biological N fixation by the legume plants, utilization of N and P and total plant yield for the two crops.1. Intercropping of rice(Oryza sativa var. Japonica Nipponbare) and mungbean (Vigna radia ta L. var. Chuanyuan) in sterilized medium was inoculated with Glomus caledonium, Acaulospora laevis and G. mosseae for both crops, and Rhizobium Leguminosarum for mungbean. It showed that all of the three AMF could result in forming of arbuscular mycorrhizal for both rice and mungbean. The inoculation rate was 12.5%-36.7% for rice and 54.8%-66.7% for mungbean. Meanwhile the promoting effect of different AMF on plant growth was varied considerably, but the infection rate、hyphal length and stimulating effect of different AMF isolates on plant growth were differed markedly, suggesting G. caledonium was the effective isolate.Inoculation AMF to the both intercropped crops increased the the acquisition of P by both crops and the leaf chlorophyll content and the growth of the mungbean very significantly. The soluble sugar content, soluble protein content in leaves of AMF-inoculated plants were also increased largely in comparison to that in untreated plant leaves. The improvement of rice and mungbean growth and physiological characters were resulted mainly from directly increased phosphorus acquisition by fungal tissues and subsequently promoting phosphorus content of inoculated plants.2. The effect of phosphate application on AMF colonization and inoculation biological response with G. caledonium in sterilized medium was evaluated by a pot experiment. The highest mycorrhizal colonization into rice was obtained in the treatment of 10 mg/kg P applied in the culture medium, while it was 20 mg/kg P for mungbean. There was no significant effect of AMF inoculation on the growth of rice/mungbean seedlings at low and middle levels of P-application (0-10 mg/kg P for rice,0-20 mg/kg P for mungbean). However, the high level of P (50 mg/kg P) inhibited AMF infection in both plant roots and alightly decreased the dry weight of inoculated rice in comparison with that non-inoculation rice. The total uptake of phosphorus, chlorophyll content in the leaves and the plant growth was imrproved and were related to the infection rate of AMF in the mungbean.3. Using the methods of plastic net and nylon membrane partition and tracing 15N transferring between the intercropped upland rice and mungbean, we assayed the contributions of inoculation with arbuscular mycorrhiza fungi (AMF), G. caledonium 90036, on nutrient acquisition and biomass yield of rice and mungbean. Treatments with separation of the whole root systems by a plastic net, with and without barrier of nylon membrane to allow penetration of the fungal hyphae were used in the intercropping system. The results demonstrated that intercropping with legume crops significantly improved the formation of arbuscular mycorrhiza, particularly in the upland rice roots. The improved inoculation of mycorrhiza by the intercropping increased total P uptake by 57% in rice, total P and N acquisition by 65% and 64% in mungbean, respectively, and 54% of nodulation in the mungbean. The percentage of total 15N transfer from mungbean to rice leaves was increased by 5.4-15.7% due to inoculation with AMF. In contrast, only 2.7% of transfer from rice to mungbean and no AMF effect were detected. It is concluded that cereal and legume crop intercropping could increase mycorrhizal innoculation, which in turn improves the nodulation, leading to N and P acquisition and N transfer in the legume.4. The effects of AMF G. caledonium on the intercropping system of rice and mungbean growth, physiological metabolism and drought resistance of rice/mungbean in pot culture under different water content were assessed. The results showed that water stress seriously repressed plant growth, but did not influence the growth and AMF infection of plants. The P and N uptake of plant could be enhanced andsubaequently improved plant water status. While the repression degree of water stress on plant growth was greatly reduced, many photosynthesis parameters of inoculated plants were obtained mainly through direct water uptake by fungal tissues and through the improvement of nutrition. The accumulation of soluble sugar decreased proline content and effectively adjusted permeation ability of cell indirectly, and promoted the drought resistance of rice/ mungbean plants.5. In a pot experiment, the effects of inoculation with thre different AMF strains on the stress of rice/mungbean were studied. Three AMF strains used are G. caledonium, A. laevis and G. mosseae and the plants were sampled at the 30,45,60 days after inoculation with AMF. The AMF treatments decreased the content of malondialdehyde(MDA) in the leaves, but significantly increased the concentrations of soluble protein, and the activity of superoxide dismutase(SOD), catalase(CAT), peroxidase (POD), phenylalanine ammonialyase(PAL) and polyphenol oxidase(PPO) in the leaves of AMF inoculated plants. It is concluded that the AMF inoculation decreased the degree of stresses of the intercropped rice/mungbean under water and nutrient deficient conditions.The present study demonstrate that inoculation of a screened AMF G. caledonium to the plants in cereal-legume intercopping system might be a novel approach to high-yield, environment-friendly and effective utilization of water and nutrient resources in agriculture production.更多还原