香格里拉葡萄产区根际土壤微生物增强作物干旱适应性的初步研究

Preliminary Study on the Enhancement of Crop Drought Adaptation by Rhizosphere Microorganisms in Shangri-La Grape Region

【目的】评价香格里拉葡萄产区赤霞珠根际土壤微生物帮助植物抵御干旱胁迫的能力,为利用微生物缓解环境胁迫对植物的不良影响提供理论依据。【方法】干旱胁迫下,比较香格里拉4个不同区域的赤霞珠根际土壤的浸提液和浸提过滤液(除去微生物)对番茄生物量及叶片中与活性氧清除相关酶含量的影响;分离(LB平板)、鉴定(16S rDNA)并筛选(对峙培养)出奔子栏葡萄园根际土壤中对尖孢镰刀菌拮抗活性较强的菌株,进一步测定干旱胁迫下拮抗菌株对番茄幼苗生长的影响。【结果】干旱胁迫下,与浸提过滤液相比,来自4个区域的土壤浸提液可以增加番茄植株的生物量,提高过氧化氢酶(CAT)和过氧化物酶(POD)的活性,增加脯氨酸(Pro)的含量,降低丙二醛(MDA)的含量。此外,从奔子栏的赤霞珠根际土壤中共分离获得90株细菌,其中有12株细菌对供试尖孢镰刀菌具有较强的拮抗活性。干旱胁迫下,大部分拮抗菌液处理后均能增加番茄幼苗的全株和茎叶鲜质量,其中来自芽孢杆菌属(TR56S44)、红球菌属(T123-S42)以及鞘氨醇单胞菌属(4TZ16)的3个菌株的效果较显著(P<0.05)。【结论】香格里拉4个产区的赤霞珠根际土壤浸提液可通过提高番茄植株体内CAT和POD活性以及增加Pro的含量来清除细胞内积累的MDA,从而增强番茄抵御干旱胁迫的能力。其中,奔子栏葡萄园赤霞珠根际土壤中分离筛选的拮抗细菌可以促进番茄幼苗的生长,增加植株茎叶及根的鲜质量,有助于缓解干旱胁迫对植物生长的影响。

[Purpose]To evaluate the ability of rhizosphere microbes from Cabernet sauvignon grown in Shangri-La grape region to help plants resist drought stress,and to provide a theoretical basis for utilizing microorganisms to mitigate the deleterious impact of environmental stress on plants.[Methods]The effects of extracts and filtrates(microorganisms removed)from C.sauvignon rhizosphere soil in four different regions of Shangri-La on tomato biomass were compared,scavenging reactive oxygen in tomato leaves under drought stress were determined.After isolation(LB plates),identification(16 S rDNA)and screening of strains which showed strong antagonistic activity against Fusarium oxysporum in the rhizosphere soil of C.sauvignon in Bengzilan area,the effect of antagonistic bacterial suspensions on the growth of tomato seedlings under drought stress was further determined.[Results]Compared with the filtrates,the soil extracts from four regions increased the biomass,the activity of catalase(CAT)and peroxidase(POD),and the content of proline(Pro),decreased the content of malondialdehyde(MDA)in tomato plants under drought stress.In addition,a total of 90 bacterial strains were isolated from the rhizosphere soil of C.sauvignon in Benzilan area,12 of which showed strong antagonistic activity against F.oxysporum.Under drought,the whole plant,stem and leaf fresh weight of tomato seedlings increased after treated by most of the antagonistic bacterial suspensions,especially three strains from Bacillus(TR56 S44),Rhodococcus(T123-S42)and Sphingomonas(4 TZ16)showed significant effects respectively(P<0.05).[Conclusion]Rhizosphere soil extracts of C.sauvignon from four regions of Shangri-La could enhance tomato resistance to drought stress by increasing CAT and POD activities and Pro contents to remove intracellularly accumulated MDA.Among them,the antagonistic bacteria strains isolated and screened from the C.sauvignon rhizosphere soil in Benzilan promoted the growth of tomato seedlings and increased the fresh weight of plant stems,leaves and roots,which relieved the drought stress on plant growth.