摘要
采用PEG6000人工模拟干旱条件下的土壤水势,将桑苗培育450d后,选出大小、长势基本一致的接种桑苗(F+)和非接种桑苗(F-)分别移栽入干旱胁迫基质中,胁迫3d后,进行光合参数及干旱生理生化指标的测定.结果表明,接种AM真菌后桑苗菌根侵染率逐渐升高,150d后趋近于稳定,达(83.27±2.55)%,接种90d菌根促生效应最为显著;桑根系活力随土壤水势的增大而增强,当达到-6.5Mpa时,对照桑根系达到最大值,而接种桑根系活力仍保持增强趋势;接种桑叶片中酶系统活力(SOD,POD,CAT)随胁迫强度增大而增强,总体呈先上升后平缓的趋势,但均高于非接种桑;随着土壤水势增大,叶片中叶绿素a、叶绿素b、叶绿素a+b和类胡萝卜素含量、光合速率、气孔导度、蒸腾速率值下降趋势愈明显,但接种桑相应测量指标始终显著高于对照.渗透调节物质脯氨酸、可溶性糖、可溶性蛋白等随土壤水势升高其含量均迅速增加,接种桑叶片渗透调节物质含量显著高于非接种桑对照.提出菌根桑耐旱生理生化的可能机制是:接种AM真菌能增强桑苗根系的活力,提高叶片保护酶活性,提高光合效率,增加叶片渗透物质含量,促进桑苗生长,抵御干旱胁迫能力得到增强.
PEG6000 was used to simulate drought with different soil water potentials（0,-4.3,-5.1,-6.5 and-8.4 Mpa）.Mulberry saplings of similar size and vigor cultivated for 450 days were inoculated with Gigaspora rosea,and the inoculated（F＋） and the non-inoculated（F-） saplings were transplanted into their respective drought stress matrices.Three days later,their photosynthetic parameters and drought chemo-physiological indexes were determined.The results showed that after inoculation with AM fungi the mycorrhizal colonization rates of mulberry root tips gradually increased up to 150 days and remained largely stabilized at（83.27±2.55）% thereafter.The promotion effect was the most remarkable after inoculation for 90 days.Root vigor increased with soil water potential,being the maximum with a water potential of-6.5 Mpa for the control（F-）,but continued to increase for the inoculation treatments（F＋）.The enzyme activities（SOD,POD and CAT） of F＋ first increased with increasing stress intensity and then became stabilized,and were always higher than those of F-.The contents of photosynthetic pigments（chlorophyll a,chlorophyll b,chlorophyll a＋b and carotenoid）,photosynthetic parameters [photosynthetic rate（Pn）,stomatal conductance（Gs） and transpiration rate（Tr）] showed an overall downward trend with increasing soil water potential.However,these parameters of F＋ were much higher than those of F-.Osmotic adjustment materials such as proline,soluble sugar and soluble protein increased rapidly with increasing soil water potential,and their contents in the leaves of F＋ were significantly higher than those of F-.A possible biochemical mechanism of the drought tolerance of the inoculated mulberry is offered in the paper： AM fungi can enhance the vigor of the root system,promote the activity of protective enzymes,improve the photosynthetic efficiency,increase the contents of osmotic adjustment materials in the leaves and accelerate the growth of mulberry,thus enhancing its ability to withstand drought stress.
出处
《西南大学学报（自然科学版）》
CAS
CSCD
北大核心
2013年第8期19-26,共8页
Journal of Southwest University(Natural Science Edition)
基金
重庆市科技攻关重点项目(CSTC
2011AB1028)
现代农业产业技术体系专项(CARS-22-ZJ0503)
关键词
AM真菌
接种桑
石漠化
耐旱性
生态修复
AM fungi
inoculated mulberry
rocky desertification
drought tolerance
ecological restoration
