菌根真菌对茶树吸收磷、钾素的影响

以辐照灭菌的酸性黄壤为供试土，种植有性繁殖的茶苗并接种ＶＡ菌根真菌，以不接种菌根真菌为对照，分别追施３２Ｐ－过磷酸钙和＾８６Ｒｂ－氯化铷，试验结果表明：菌根侵染率，＾３２Ｐ组合合为５２．６０％，＾８６Ｒｂ组合为５６．７０％，茶树株高分别对照的２．１０倍和２．５０倍，对磷、钾元素的吸收量分别比对照增加４．６０和３．１０倍，磷肥利用率提高１４．１０％，钾肥利用率提高１７．１３％。     

A菌根真菌外生菌丝对难溶性无机磷酸盐的活化及利用Ⅰ.~(32)P间接标记法

采用三室栽培装置培养三叶草 ,接种VA菌根真菌Glomusmosseae。将根系与VA菌根真菌外生菌丝隔开 ,在菌丝室施用 5种磷酸盐和32 P间接标记磷肥 ,研究外生菌丝对难溶性磷酸盐的活化利用能力。结果表明 ,外生菌丝可以活化吸收磷酸二钙、磷酸八钙、磷酸铝和磷酸铁 ,无法活化利用磷酸十钙 ;各种磷酸盐被活化吸收的量及其对三叶草磷营养的贡献率的大小顺序是磷酸二钙 >磷酸八钙、磷酸铝 >磷酸铁     

Ecology of soil microflora and mycorrhizal symbionts in degraded forests at two altitudes

Summary Microbial populations were estimated in four different forest stands at different regenerational stages, two each at higher and lower altitudes. The fungal and bacterial populations showed marked seasonal variations at both altitudes. Quantitatively, the bacterial population was higher than the fungal population. Although 25 fungal species were isolated at the lower altitude, only 15 were obtained at the higher altitude. Penicillium chrysogenum and Trichoderma viride were dominant at the lower and higher altitudes, respectively. In the more degraded forest stand at the lower altitude both the fungal and the bacterial population showed a significant positive correlation with organic C (r=0.658 and 0.735, respectively), whereas in the less degraded forest stand there was a significant correlation only between the fungal population and organic C (r=0.835). At the higher altitude, however, a highly significant correlation (P<0.05) was observed between the fungal population, soil moisture and organic C in both the forest stands. Disturbance to the soil and vegetation adversely affected the microbial population, and also affected endogonaceous spores. At the lower altitude, plants in the more degraded forest stand were more mycotrophic compared to those in the less degraded stand. The level of mycorrhizal infection showed a highly positive correlation with soil moisture, organic C, total N, and available P. The spore population, however, was correlated negatively with these parameters. Three different endogonaceous genera, Glomus, Gigaspora, and Acaulospora, were identified during the course of investigation. Glomus, however, was dominant.     

Soil pH,rhizobia, and vesicular-arbuscular mycorrhizae inoculation effects on growth and heavy metal uptake of alfalfa (Medicago sativa L.)

Summary The interaction between soil pH and inoculation with rhizobia and vesicular-arbuscular mycorrhizae (VAM) was studied in an industrially polluted soil contaminated with high levels of Zn and Cd. A silt loam soil (pH 6.7) was amended with Ca(OH)₂ or elemental S to adjust the soil pH to 4.3, 5.3, 6.0, and 7.2. Alfalfa (Medicago sativa L.) was planted in each treated soil an subsequently inoculated with Rhizobium meliloti and/or a mixed VAM spore population. Alfalfa growing in soils at a pH of 4.3 and 5.3 failed to survive as a result of soil acidity and heavy metal toxicity. At the three higher pH values, growth and foliar N and P were significantly increased by inoculation with rhizobia or VAM. The greatest increase was observed when both VAM and rhizobia were inoculated together into the soil. With a soil pH of 6.0 and 6.7, the available heavy metal concentration in the soil was high and the VAM significantly decreased heavy metal uptake from these soils. The foliar concentration of Zn was reduced from 455 to 306 g g^–1 by inoculation with VAM (pH 6.0). At the highest soil pH (7.2), however, available heavy metal concentrations were generally lower and NAM significantly increased the heavy metal uptake. The influence of VAM on heavy metal uptake thus appears to be partly a function of the available heavy metal content in the soil.     

Arbuscular Mycorrhizal （AM） Diversity in Prosopis cineraria （L.） Druce Under Arid Agroecosystems

Arbuscular mycorrhizal （AM） fungi associated with Prosopis cineraria （Khejri） were assessed for their qualitative and quantitative distribution from eight districts of Rajasthan. A total of three species of Acaulospora, one species of Entrophospora, two species of Gigaspora, twenty-one species of Glomus, seven species of Sclerocystis and three species of Scutellospora were recorded. A high diversity of AM fungi was observed and it varied at different study sites. Among these six genera, Glomus occurred most frequently. Glomus fasciculatum, Glomus aggregatum, and Glomus mosseae were found to be the most predominant AM fungi in infecting Prosopis cineraria. Acaulospora, G. fasciculatum, Sclerocystis was found in all the fields studied, while Scutellospora species were found only in few sites. A maximum of thirty-six AM fungal species were isolated and identified from Jodhpur, whereas only thirteen species were found from Jaisalmer. Spores of Glomusfasciculatum were found to be most abundant under Prosopis cineraria.     

铁与维生素A及其互作效应对蛋鸡微量元素铁、锰、锌表观存留率的影响

选用210日龄蛋鸡432只,随机分为6组,每组6个重复,每重复12只鸡,采用3×2(Fe×VA)完全随机试验设计,研究日粮中不同水平Fe和VA对蛋鸡产蛋高峰期(30～33周龄和34～37周龄)铁、锰、锌表观存留率的影响。日粮铁的添加量分别为0、30、60mg/kg,VA的添加量分别为4000、8000IU/kg。结果表明:日粮不同铁水平对前后期铁、锰表观存留率影响均显著(P<0.05);日粮VA水平对前后期铁表观存留率的影响均显著(P<0.05);对后期锰表观存留率影响显著(P<0.05);对前期锌表观存留率影响显著(P<0.05);铁和维生素A的交互作用对前后期铁、锰、锌表观存留率的影响均显著(P<0.05)。结果表明日粮中铁添加量为30mg/kg、VA添加量为4000IU/kg时蛋鸡Fe、Mn、Zn表观存留率最佳。     

水分胁迫条件下接种菌根对玉米抗旱性的影响

采用土培试验研究了水分胁迫条件下接种菌根对玉米生长发育、光合作用、养分吸收和水分利用的影响。结果表明：土壤干旱使植株地上部及根系的生长量比对照显著下降，植株的形态发育受到抑制；接种VA菌根菌的植株体内磷营养状况得到改善，提高了土壤磷的有效利用率。接种菌根减轻了水分胁迫对植株生长的抑制程度，提高了植株叶片光合强度，增加了干物质积累。试验结果表明，菌根可以改善植株的水分状况，使叶片相对含水量增加，复水试验表明菌根植物比非菌根植林从干旱逆境中恢复水分的速度要快得多，同时也提高了植株水分利用效率。     

接种丛枝菌根菌对黄檗苗木主要3种生物碱含量的影响

在盆栽条件下,研究了接种丛枝菌根菌对黄檗实生苗主要药用成分含量的影响。结果表明,接种丛枝菌根菌显著增加了黄檗重要的药用成分小檗碱、药根碱及掌叶防己碱的含量,其中尤以接种摩西球囊霉和透光球囊霉的处理效果显著。     

马尾松离体培养条件下的微繁殖和菌根的形成*

以马尾松种胚作外植体进行不定芽诱导。基本培养基的种类对外植体不定芽的诱导起着决定性的作用，在ＧＤ附加２．０ｍｇ／ＬＢＡ的培养基上，外植体不定芽诱导率达７０％以上。ＩＡＡ或ＮＡＡ的加入不利于外植体不定芽的诱导。在不定芽生长培养基中，加入适量的ＩＢＡ能促进不定芽的伸长生长。伸长至０．５ｃｍ以上的嫩枝在１／２ＧＤ附加４．０ｍｇ／ＬＩＢＡ的培养基上，生根状况良好。生根后的小植株，在１／２ＧＤ培养基上接种Ｒｔ４９菌根真菌，菌丝侵染进入根部，形成组培菌根植株。