生态环境学报
生態環境學報
생태배경학보
ECOLOGY AND ENVIRONMENT
2014年
3期
477-484
,共8页
桑树%重金属%丛枝菌根%土壤pH%有机分泌物
桑樹%重金屬%叢枝菌根%土壤pH%有機分泌物
상수%중금속%총지균근%토양pH%유궤분비물
mulberry%heavy metal%arbuscular mycorrhizael%soil pH%organic exudate
桑树(Morus alba)可与丛枝菌根(AM)真菌形成互利共生体,丛枝菌根真菌能对桑树的重金属元素吸收产生积极的响应。然而,这种响应随环境条件的变化而有所不同。贵州荔波和黄平两地种植养蚕桑树,提高桑叶质量对养蚕业具有重要意义。荔波和黄平两地均处于喀斯特地区,土壤pH因石灰岩和砂岩交叉分布而有所差异。本文将揭示土壤因素是如何影响桑树与丛枝菌根真菌互利共生体的形成从而影响桑树对重金属元素的吸收。实验结果表明,荔波桑地平均土壤 pH (4.92±1.03)明显低于黄平(5.96±1.08)。土壤酸性直接影响 AM 真菌的分布,荔波的偏酸性土壤环境有利于真菌生长,且有利于桑树与丛枝菌根真菌共生关系的形成。此外,偏酸性土壤条件有利于增加重金属元素的生物可利用性,从而加强植物体对重金属元素的吸收,包括有毒元素 Cd。与黄平相比,生长在荔波的桑树叶片具有较高含量的重金属元素。荔波桑树叶片中的糖类含量明显低于黄平的,分别为(67±27)mg·g-1、(105±57)mg·g-1;而荔波桑树根系中的糖类含量明显高于黄平,分别为(125±43)mg·g-1、(91±43)mg·g-1。该结果说明,与黄平(具有较高的土壤pH)相比,荔波(具有较低的土壤pH)桑树叶片中的光合作用产物将更多地被输入到桑树的根系中。真菌是专性共生物,如果没有植物所供给的光合产物,真菌就不能生存。根系分泌物的另一个重要作用是溶解重金属,使它们具有较强的移动能力,以便被宿主植物所吸收。这就解释了为什么在较低土壤pH环境条件下生长的桑树的叶片含有较高含量的重金属元素。因此,菌根植物根系的分泌作用是一个非常重要的过程。尽管桑树具有耐干旱贫瘠的能力,且能够适应于喀斯特环境,但桑树喜好的是环境仍是偏酸性且养分充足的土壤。
桑樹(Morus alba)可與叢枝菌根(AM)真菌形成互利共生體,叢枝菌根真菌能對桑樹的重金屬元素吸收產生積極的響應。然而,這種響應隨環境條件的變化而有所不同。貴州荔波和黃平兩地種植養蠶桑樹,提高桑葉質量對養蠶業具有重要意義。荔波和黃平兩地均處于喀斯特地區,土壤pH因石灰巖和砂巖交扠分佈而有所差異。本文將揭示土壤因素是如何影響桑樹與叢枝菌根真菌互利共生體的形成從而影響桑樹對重金屬元素的吸收。實驗結果錶明,荔波桑地平均土壤 pH (4.92±1.03)明顯低于黃平(5.96±1.08)。土壤痠性直接影響 AM 真菌的分佈,荔波的偏痠性土壤環境有利于真菌生長,且有利于桑樹與叢枝菌根真菌共生關繫的形成。此外,偏痠性土壤條件有利于增加重金屬元素的生物可利用性,從而加彊植物體對重金屬元素的吸收,包括有毒元素 Cd。與黃平相比,生長在荔波的桑樹葉片具有較高含量的重金屬元素。荔波桑樹葉片中的糖類含量明顯低于黃平的,分彆為(67±27)mg·g-1、(105±57)mg·g-1;而荔波桑樹根繫中的糖類含量明顯高于黃平,分彆為(125±43)mg·g-1、(91±43)mg·g-1。該結果說明,與黃平(具有較高的土壤pH)相比,荔波(具有較低的土壤pH)桑樹葉片中的光閤作用產物將更多地被輸入到桑樹的根繫中。真菌是專性共生物,如果沒有植物所供給的光閤產物,真菌就不能生存。根繫分泌物的另一箇重要作用是溶解重金屬,使它們具有較彊的移動能力,以便被宿主植物所吸收。這就解釋瞭為什麽在較低土壤pH環境條件下生長的桑樹的葉片含有較高含量的重金屬元素。因此,菌根植物根繫的分泌作用是一箇非常重要的過程。儘管桑樹具有耐榦旱貧瘠的能力,且能夠適應于喀斯特環境,但桑樹喜好的是環境仍是偏痠性且養分充足的土壤。
상수(Morus alba)가여총지균근(AM)진균형성호리공생체,총지균근진균능대상수적중금속원소흡수산생적겁적향응。연이,저충향응수배경조건적변화이유소불동。귀주려파화황평량지충식양잠상수,제고상협질량대양잠업구유중요의의。려파화황평량지균처우객사특지구,토양pH인석회암화사암교차분포이유소차이。본문장게시토양인소시여하영향상수여총지균근진균호리공생체적형성종이영향상수대중금속원소적흡수。실험결과표명,려파상지평균토양 pH (4.92±1.03)명현저우황평(5.96±1.08)。토양산성직접영향 AM 진균적분포,려파적편산성토양배경유리우진균생장,차유리우상수여총지균근진균공생관계적형성。차외,편산성토양조건유리우증가중금속원소적생물가이용성,종이가강식물체대중금속원소적흡수,포괄유독원소 Cd。여황평상비,생장재려파적상수협편구유교고함량적중금속원소。려파상수협편중적당류함량명현저우황평적,분별위(67±27)mg·g-1、(105±57)mg·g-1;이려파상수근계중적당류함량명현고우황평,분별위(125±43)mg·g-1、(91±43)mg·g-1。해결과설명,여황평(구유교고적토양pH)상비,려파(구유교저적토양pH)상수협편중적광합작용산물장경다지피수입도상수적근계중。진균시전성공생물,여과몰유식물소공급적광합산물,진균취불능생존。근계분비물적령일개중요작용시용해중금속,사타문구유교강적이동능력,이편피숙주식물소흡수。저취해석료위십요재교저토양pH배경조건하생장적상수적협편함유교고함량적중금속원소。인차,균근식물근계적분비작용시일개비상중요적과정。진관상수구유내간한빈척적능력,차능구괄응우객사특배경,단상수희호적시배경잉시편산성차양분충족적토양。
Mulberry is colonized by Arbuscular mycorrhizal (AM) fungi. The AM symbiosis is important for heavy metal absorption by host mulberry. However, the symbiont of mulberry with AM fungi should change with various soil conditions. Mulberry is usually established for sericulture in Libo and Huangping areas of southwest China. Therefore, the leaf quality is important for sericulture. Libo and Huangping are located in limestone areas, among where sandstone distributed, resulting in different soil pH in collected samples in both Libo and Huangping. Our results showed that average soil pH of Libo soils (4.92±1.03) was significantly lower than that of Huangping soils (5.96±1.08). Soil acidity directly affects the distribution of AM fungi. Relatively lower soil pH of Libo soils should be favorable to the growth of fungi, therefore, to the formation of symbionts, resulting in higher bioavailability of heavy metals in soils, and higher absorption of heavy metals by mulberry. In addition, sugar concentration of mulberry foliage from Libo (67±27) mg·g-1 was significantly lower than that from Huangping (105±57) mg·g-1, but sugar concentration of mulberry roots from Libo (125±43) mg·g-1was significantly higher than that from Huangping (91±43) mg·g-1 Those results indicate that compared with Huangping (with higher soil pH), more products of photosynthesis enter to roots from Libo (with lower soil pH). Fungi are obligated symbionts and cannot survive without photosynthate supply from plants. Another role of root exudates is the solubility of heavy metals, resulting in higher ability of movements, and easily absorption by host plants. Therefore, it is why mulberry foliagein from Libo with lower soil pH having higher concentrations of heavy metal. Although mulberry can adapt to Kast areas with drought and poor nutrients of environments, their favorable soil is relatively acidified with rich nutrients.