The effects of cadmium (Cd) on germination,and antioxidative enzyme activity (AEA) involving superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase, and on amounts of malondialdehyde and proline present within Achnatherum inebrians, were determined for specimens infected (E?) vs. non-infected (E-) by Neotyphodium gansuense, and cultivated in the presence of various concentrations of CdCl2 (0, 50, 100, 200 and 300 lmol/l). Under high Cd concentrations (100, 200 and 300 lM), E? (vs. E-) specimens exhibited a higher germination rate and index, and higher values for shoot length, root length and dry biomass, but there was no significant difference (P[0.05) under low Cd concentrations (0 and 50 lM). AEA and the proline content increased, but malondialdehyde content declined in the E? (vs. E-) specimens under high Cd concentrations (100, 200 and 300 lM). There was no significant difference (P[0.05) under low Cd concentrations (0 and 50 lM). Endophyte infection was concluded to be of benefit to the germination and anti-oxidative mechanisms within A. inebrians under plant exposures to high CdCl2 concentrations.

Interactions of Neotyphodium gansuense, Achnatherum inebrians, and nine fungal pathogens were studied by tests of inhibition of four fungal pathogens by Neotyphodium endophytes in vitro and by inoculation of nine fungal pathogens on detached leaves of endophyteinfected (Et) and endophyte-free (E_) plants. Compared with the controls, most isolates of N. gansuense significantly inhibited the growth in vitro of, in decreasing order of inhibition, Bipolaris sorokiniana, Curvularia lunata, Fusarium acuminatum, and Alternaria alternata. Inhibition zones appeared between pathogens and some isolates of N. gansuense. Some isolates of N. gansuense significantly inhibited sporulation of B. sorokiniana, A. alternata, and C. lunata. However, there was no significant inhibition of F. acuminatum and a few isolates significantly increased sporulation. The leaf inoculation trial indicated that almost all fungal pathogens were able to cause lesions on detached leaves regardless of endophyte status. Both the number and size of disease lesions on Et A. inebrians leaves caused by A. alternate.

Biological and physiological characteristics of Neotyphodium gansuense were compared with Neotyphodium coenophialum and Epichloe festucae at a range of temperatures and pH values, and on carbon and nitrogen amended media. N. gansuense was able to grow at 10-30 1C, but not at 51C, and slowly at 351C. The optimal temperature for both N. gansuense and N. coenophialum was 251C, but that of E. festucae was 20-25 1C. The optimal pH ranges for mycelial growth of N. gansuense, N. coenophialum and E. festucae were 5-9, 5-9 and 5-7, respectively. The Neotyphodium and Epichloe

The effect of the endophyte Neotyphodium lolii on susceptibility of perennial ryegrass (Lolium perenne) to ten fungal pathogens in detached leaves was studied. The pathogens were Alternaria alternata, Ascochyta leptospora, Bipolaris sorokiniana, Curvularia lunata, Fusarium acuminatum, F. avenaceum, F. chlamydosporum, F. solani, F. oxysporum, and Gliocladium roseum. In addition, the effect of the endophyte on four pathogens (A. alternata, B. sorokiniana, Curvularia lunata and F. avenaceum) in living plants was studied, and changes in host superoxide dismutase (SOD) or peroxidases (POD) activity were examined. The total lengths of lesions on detached leaves were greater (P<0.05) on Eplants than on E+ plants except for A. leptospora although differences between E+ and E- were not consistently significant at all sample times (days after inoculation).The numbers of lesions were greater (P< 0.05) and the lesions were larger (P<0.05) on intact E- plants than on intact E+ plants for all of the four pathogens. SOD enzyme activity was significantly greater (P<0.05) in E+ plants than in E- plants only for A. alternata, C. lunata, and F. avenaceum. POD enzyme activity was significantly greater (P<0.05) in E+ plants than in E- plants only for C. lunata, B. sorokiniana and the uninoculated control.

土壤湿度是影响蚕豆(V icia f aba L.) 生长和根腐病发生的主要环境因素之一。本文以来源于蚕豆产区的田间土壤, 分别以30%、50% 和70% 的土壤饱和持水量(WHC) 处理进行盆栽试验, 在室外自然条件下生长, 测定了出苗率、出苗速度、株高、生长速度、叶面积、总叶绿素含量、净光合速率、结荚数、根瘤数、生物量干重、根腐病严重度及死亡率。结果表明50%WHC 的土壤含水量为蚕豆生长的最佳土壤湿度, 有利于蚕豆健康生长, 减少根腐病的发生与危害。在30%、50% 和70%WHC 土壤湿度条件下, 播后10 周蚕豆生物量干重和植株的死亡率依次分别为1.53、3.16、2.68 g 和18.5%、4.8%、25.6%。