10色板对鲜食葡萄3种主要害虫的诱捕效果

利用10种颜色制成的粘虫板于2011年5月7日至2011年11月1日在鲜食葡萄(莫尔格瓦)上测试了葡萄主要害虫绿盲蝽、葡萄二星叶蝉以及葡萄二黄斑叶蝉3种害虫成虫对不同颜色粘虫板的诱捕效果。结果表明,10种色板诱捕到绿盲蝽数量较多,而诱捕到二星叶蝉和二黄斑叶蝉数量较少。经方差分析,米黄、黄色诱捕绿盲蝽效果最好,深绿、绿色、白色、土黄、红色居中,深蓝其次,最差的是黑色、天蓝色,且差异显著;诱捕的另外两种害虫二星叶蝉和二黄斑叶蝉,分别以土黄、黄色,土黄、黑色、米黄色效果最好。     

裸脚菇0612-9提取物对柑橘青、绿霉的抑菌活性及作用机制

为探索裸脚菇0612-9提取物(GSFE)对意大利青霉(Penicillium italicum)和指状青霉(P. digitatum)的抑菌活性和作用机理,本试验采用菌丝生长速率法测定GSFE对意大利青霉和指状青霉的抑菌活性,分析GSFE处理后意大利青霉和指状青霉的菌丝形态、细胞膜通透性和麦角固醇含量变化情况,并通过靶位竞争剂试验探究GSFE的抑菌机理。结果表明,GSFE对意大利青霉和指状青霉的半有效浓度(EC₅₀)值分别为116.76和147.74 μg·mL^-1,最小抑菌浓度(MIC)均为200 μg·mL^-1;经质量浓度为EC₅₀和MIC的GSFE处理后意大利青霉和指状青霉菌丝体均发生严重的皱缩、干瘪,并且胞内呈空泡状结构,细胞质大量减少,胞外相对电导率显著上升,菌体内核酸、可溶性蛋白等胞内物质含量显著降低。这表明意大利青霉和指状青霉细胞膜通透性增加,胞内物质外泄,细胞膜完整性遭到破坏。经浓度为EC₅₀的GSFE处理的意大利青霉和指状青霉菌丝体,其麦角固醇含量均显著降低,分别仅为对照组的17.92%和20.13%。由此可见,GSFE主要通过抑制意大利青霉和指状青霉菌丝体的麦角固醇合成而损伤病原真菌细胞膜的结构和功能。本研究结果为后续开发新型微生物源柑橘采后保鲜剂提供了设计思路。     

Using arbuscular mycorrhiza to alleviate the stress of soil compaction on wheat (Triticum aestivum L.) growth

Since large areas of agricultural fields in the world become compacted every year, much effort has been made to reduce the adverse effects of soil compaction on plant growth. Mechanical methods to control soil compaction may be laborious and expensive; however, biological methods such as using arbuscular mycorrhiza (AM) may be more useful, economically and environmentally. The objectives of this study were: (1) to evaluate the effects of soil compaction on wheat (Triticum aestivum L.) growth, and (2) to evaluate if using AM of different origin can reduce the stressful effects of soil compaction on wheat growth. Unsterilized and sterilized soils, different levels of compaction and three species of arbuscular mycorrhiza were applied in four replicates. The experiments were conducted in the Soil and Water Research Institute, Karaj, Iran. Soil physical and chemical properties were determined. The AM increased wheat growth in both soils at different levels of soil compaction in both experiments. For root, shoot (P=0.1) and grain (P=0.05) dry weights increases were significant. AM enhanced root growth more than shoot growth under compaction (AM resulted in significant increase in root/shoot ratios, P=0.1). Due to its unique characteristics, AM may reduce the stressful effects of soil compaction on wheat growth, though its effectiveness may decrease with increasing compaction.     

Enhancing micronutrient uptake and yield of wheat through bacterial PGPR consortia

A pot experiment was undertaken under net house conditions, with three rhizobacterial strains AW1 (Bacillus sp.), AW5 (Providencia sp.) and AW7 (Brevundimonas sp.), applied along with 2/3 recommended dose of nitrogen (N) and full dose of phosphorus (P) and potassium (K) fertilizers (N₉₀P₆₀K₆₀). An enhancement of 14–34% in plant biometric parameters and 28–60% in micronutrient content was recorded in treatments receiving the combination of AW1?+?AW5 strains, as compared to full dose of fertilizer application. The treatment involving inoculation with AW5?+?AW7 recorded highest values of % P and N, with a two-fold enhancement in phosphorus and 66.7% increase in N content, over full dose application of P and K fertilizers. A significant correlation was recorded between plant biomass, panicle weight, grain weight, N, P and iron (Fe) with acetylene reduction activity, indicating the significance of N fixation in overall crop productivity. Our study illustrates the multiple benefits of plant growth promoting rhizobacteria (PGPR) inoculation in integrated nutrient management and biofortification strategies for wheat crop.     

Mechanism of induced systemic resistance against anthracnose disease in cucumber by plant growth-promoting fungi

Plant growth-promoting fungi (PGPF) such as Phoma sp. (isolates GS8-1, GS8-2 and GS8-3) and non-sporulating fungus (isolate GU21-2) were tested for their ability to induce systemic resistance against Colletotrichum orbiculare in cucumber. These isolates, used as colonized barley kernels to natural soils, induced systemic resistance in the greenhouse as well as in the field. Different elicitors from PGPF such as cell walls retaining or lacking protein and lipids, cell walls lipid fraction, and three fractions of culture filtrate (CF) with different molecular weight ranges were tested for their ability to elicit the defense response of cucumber plants under controlled conditions. Cell wall fraction lacking protein and lipids and the cell wall lipid fraction from root colonizing isolates GS8-1, GS8-2, and GS8-3 protected plants against C. orbiculare. While, only cell wall lipid fraction and CF fractions of different molecular weight ranges of the isolate GU21-2 protected plants against C. orbiculare infection. Methanol-soluble substances from CF fractions with molecular weight greater than 12,000 and less than 8000 consistently protected plants against the pathogen. Germination of C. orbiculare spores decreased significantly at 72 h of incubation on leaves of PGPF-protected plants. Isolate GU21-2 was the most effective in inhibiting spore germination. On the other hand, isolates GS8-1 and GU21-2 induced lignifications in the hypocotyls of seven-day-old cucumber seedlings after challenge inoculation with C. orbiculare. Three-week-old cucumber plants treated with isolate GU21-2 and challenged with C. orbiculare showed increased activities of exo- and endo-forms of glucanase and chitinase, as well as peroxidase and polyphenol oxidase in the second true leaves. Induction treatment with isolate GS8-1 also increased the activities of these enzymes with the exception of exo-glucanase. This study shows that the inoculation of PGPF or its CF resulted in additive effect on the suppression of anthracnose disease in cucumber.     

Responses of root-feeding nematodes (Helicotylenchus spp.) to local and non-local populations of the host plant Ammophila arenaria

The root-feeding nematode community of wild plants may vary throughout their natural range. Little is known about how the variation of wild plants along their range affects their relationship with root-feeding nematodes. In the present study, we examined local and non-local combinations of host plants and root-feeding nematodes to test the hypothesis that nematode reproduction is favoured by local hosts. In two indoor experiments, we exposed populations of the wild dune grass Ammophila arenaria from northern and southern European coastal sand dunes to plant parasitic nematode species (Helicotylenchus spp.) from those same geographical origins. First, we used the southern nematode species to determine whether the effect of a local versus a non-local host may depend on nematode density. Then, in a cross-inoculation experiment we investigated how both nematode species performed with their local, as compared to the non-local hosts.

In both experiments, plant biomass and ontogenetic characteristics were not significantly different between the northern and southern populations. The applied nematode densities did not have a negative impact on plant performance. This allowed us to consider the response of the two different nematode species and their host plants without co-varying differences in plant responses. Reproduction of the nematode species differed according to host origin, but contrary to what we expected, nematode species did not perform better on their local hosts. Helicotylenchus n. sp., the southern species originating from Portugal, performed better on the non-local than on the local host. Male to female ratios were significantly different between the two nematode populations and were lowest in Helicotylenchus pseudorobustus from The Netherlands. Female and juveniles percentages were also quite distinct, with more females in the nematode species from The Netherlands and more juveniles in the nematode species from Portugal.

We concluded that ectoparasitic root-feeding nematodes Helicotylenchus spp. do not necessarily perform best on their local host population of the foredune grass A. arenaria. Our results imply that the natural distribution of Helicotylenchus spp. along the European coast is determined by other factors than host populations. These other factors that could be abiotic, e.g. water availability, or biotic, e.g. local natural enemies adapted to Helicotylenchus spp. Introducing plant genotypes from other parts of the natural range will, therefore, not necessarily lead to reduced abundance of semi-endo or ectoparasitic root-feeding nematodes.     

1株产碱性木聚糖酶的芽胞杆菌的分离鉴定及其相关研究

分离到1株产碱性木聚糖酶的革兰氏阳性菌株,通过菌落形态及16srDNA序列同源性分析,确定该菌株为短小芽孢杆菌。生长条件和产酶条件研究结果显示,最适温度和pH分别为50℃和pH8·0。培养基优化试验显示在有机和无机混合氮源条件下(NH4NO30·57%;牛肉膏1%;蛋白胨0·5%;酵母提取物0·5%;木聚糖0·5%)木聚糖酶产量达到最高(180U/mL)。酶学试验表明最适反应条件为50℃,pH8~9;在pH9的条件下,孵育120min时仍具有75%的活力,表明该酶具有较强的碱耐受性。     

2种草本植物根系对长汀县崩岗洪积扇土壤水分状况的影响

植被恢复是防治崩岗侵蚀的重要方法,为研究植物根系对崩岗洪积扇土壤水分状况的影响,以崩岗洪积扇上种植的深根系巨菌草和浅根系宽叶雀稗为研究对象,对其分层取样后,用环刀法测定土壤的密度、孔隙度和最大持水量等物理性质,计算土壤蓄水能力,并用WinRHIZO根系分析系统,测定根长和密度等参数.结果表明:巨菌草和宽叶雀稗的各根系特征指标,均随土层深度的增加而减小,巨菌草各根系指标均大于宽叶雀稗;有植被覆盖下的土壤密度均小于裸地,植被覆盖下土壤总孔隙度和毛管孔隙度均大于裸地,且随土层深度的增加而减小;有植被根系的土壤饱和蓄水量和毛管蓄水量均比裸地高,且与裸地差异显著;在土壤表层,宽叶雀稗增加土壤孔隙性和土壤保水能力大于巨菌草,而在土壤中深层,则巨菌草大于宽叶雀稗;根系改善土壤性质的能力,主要取决于其根长密度和根系总表面积,直径小于0.5mm的根系是影响土壤水分的最主要因子.研究植物根系对改良土壤水分状况的影响,以期为崩岗侵蚀防治中植被种类的筛选和推广提供依据.     

柰园留草对柰园温湿度和柰果质量的影响

1999～2001年在古田县农科所红壤油柰母本园进行了果园留草对柰园温湿度和柰果质量影响的观测试验。结果表明：采用果园留草方式可调节和改善柰园的温湿度，有效地改善柰园生态环境，减轻久旱暴雨后的裂果率，有利于提高柰果的商品质量和经济效益。     

铜耐性优势植物根际土壤铜抗性菌株的筛选及其对铜的促溶作用

从铜矿废弃地重金属耐性优势植物根际土壤中分离筛选到两株抗高浓度Cu的细菌菌株HQN2和JYC17.对菌株HQN2和JYC17溶解难溶性Cu的作用进行了研究.结果表明:菌株HQN2和JYC17具有明显的溶解碳酸铜的能力,与接灭活菌对照相比,菌株HQN2和JYC17分别使培养液中水溶性Cu含量增加306%和136%,培养液的pH由初始的7.00分别降低到4.08和4.46.另外,Cu能促进供试菌株有机酸(葡萄糖酸、苹果酸和乙酸等)的合成.菌株HQN2和JYC17对土壤中难溶性Cu亦有明显的促溶作用.与接灭活菌对照相比,菌株JYC17和HQN2分别使土壤中交换态Cu含量增加110%和270%.经生理生化特征分析及16S rDNA序列分析,菌株HQN2和JYC17分别被鉴定为节杆菌属(Arthrobacter sp.)和微杆菌属(Microbacterium sp.).