广西芒果树叶片苔藓发生情况调查及药剂筛选试验

对广西芒果树叶片苔藓的发生情况及防治药剂进行了初步研究?调查了广西芒果主产区的南宁市(武鸣区?兴宁区)和百色市(田东县?田阳县?田林县和右江区)?在南宁市开展4种药剂的18种不同浓度或者配比组合的药剂筛选试验?结果表明, 南宁市芒果树叶片平均发病率达到88.5%, 右江区发病率为81.7%, 其后依次为田东县?田林县和田阳县, 发病率分别为56.1%?54.8%和34.2%?通过不同药剂及其不同配比药效试验, 80%乙蒜素乳油的防效极显著优于46%氢氧化铜水分散粒剂?32%唑酮·乙蒜素乳油和70%甲基硫菌灵可湿性粉剂?80%乙蒜素乳油500倍液?1 000倍液和1 500倍液的防效分别为93.37%?85.82%和51.85%?综上, 芒果树叶片苔藓已在广西全区普遍发生, 南宁市和右江区受害严重, 推荐使用80%乙蒜素乳油1 000倍液防治?     

喀斯特森林近地表层覆盖对碳酸盐岩红土蒸发过程的影响

蒸发是西南喀斯特地区薄层土壤水分损失的主要途径,浅层土壤水分的存蓄对喀斯特地区农业生产和生态恢复至关重要。以西南喀斯特森林碳酸盐岩红土为研究对象,基于室内蒸渗试验设置4个苔藓生物量(0,0.32,0.64,0.95 kg/m~2)和3个松针生物量(0,0.32,0.64 kg/m~2)共12种处理,分析森林近地表层覆盖对碳酸盐岩红土蒸发过程及表层温度时空分布的影响规律,并对比3种蒸发模型(Black、Rose、空气动力学蒸发模型)在喀斯特森林碳酸盐岩红土的适用性。结果表明:苔藓和松针覆盖显著降低累积蒸发量和蒸发速率(P0.05),接种苔藓0.95 kg/m~2和覆盖松针0.64 kg/m~2处理比裸土累积蒸发量小36.9%;苔藓和松针导致土壤含水量显著增加(P0.05);苔藓和松针增加了表层土壤的平均温度,松针对土壤温度的提升作用强于苔藓;Black、Rose和空气动力学模型均能较好地模拟碳酸盐岩红土蒸发过程,Black蒸发模型的拟合精度高于Rose和空气动力学蒸发模型。研究结果能为西南喀斯特地区的水量平衡分析提供理论支撑并加强对喀斯特森林地表水文过程的认知。     

肚倍蚜,美灰藓最佳生态条件与肚倍基地建设

肚倍蚜，美灰藓最佳生态条件研究表明，由光照强度、湿度以及风速等因素决定的环境是制约肚倍丰产、稳产的关键；据此对肚倍基地建设提出若干建议。     

Pyrosequencing Reveals Significant Changes in Microbial Communities Along the Ecological Succession of Biological Soil Crusts in the Tengger Desert of China

Biological soil crusts (BSCs) have important ecological functions in arid and semiarid lands, but they remain poorly understood in terms of the changes in microbial communities during BSC succession under in situ field conditions. Here, 454 pyrosequencing was used to assess the microbial community composition of four BSC types in the Tengger Desert of China: alga, lichen (cyanolichen and green alga-lichen), and moss crusts, representing early, middle, and final successional stages of BSCs, respectively. The results showed the highest diversity of microbial communities inhabiting lichen crusts, whereas the lowest diversity was observed in moss crusts. Five phyla, Proteobacteria, Actinobacteria, Cyanobacteria, Bacteroidetes, and Acidobacteria, accounted for about 72% to 87% of total prokaryotic sequences in different BSCs. The most abundant eukaryotic microorganism was Ascomycota, accounting for 47% to 93% of the total eukaryotic sequences. Along the succession of BSCs, the abundance of photoautotrophic Cyanobacteria, Chlorophyta, and Bacillariophyta declined, and that of heterotrophic microorganisms such as bacteria and fungi increased. Statistical analysis showed clear divergency of microbial taxa at the class level among the different successional stages of BSCs. The clustering results at class level showed that the moss crusts were the farthest from the rest in prokaryotic composition; the alga crusts were the most different in terms of eukaryotic microorganisms and the two kinds of lichen crusts were relatively closer in both compositions. Ordination analysis showed that the main variations of community structure among BSCs could be explained best by the abundance of Cyanobacteria and Ascomycota and by physiochemical properties of BSCs, including mechanical composition, moisture, and electrical conductivity. In conclusion, our results indicate that Cyanobacteria and Ascomycota likely play an important role in the evolution of BSC structure and functions and highlight the importance of environmental factors in shaping microbial community structures of BSCs in the Tengger Desert of China.     

4种营养物质对藓结皮形成发育的影响

【目的】研究葡萄糖以及含氮、磷、钾、镁的营养物质对藓结皮形成发育的影响,为黄土丘陵区生物土壤结皮的人工修复提供技术指导。【方法】以陕北黄土丘陵区自然发育的藓结皮为繁殖材料,进行室内人工培养试验,在培养基中分别添加不同质量浓度的葡萄糖(10,20,30,40,50 g/L)、硝酸铵(0.5,1.0,2.0,4.0,8.0 g/L)、磷酸二氢钾(0.5,1.0,2.0,4.0,8.0 g/L)、硫酸镁(0.25,0.5,1.0,2.0,4.0 g/L),以不添加营养物质为空白对照(CK),当藓结皮生长30 d时,测定藓结皮盖度、藓株密度和藓株高,研究以上营养物质对藓结皮形成发育的影响。【结果】1)添加的4种营养物质中,用葡萄糖处理时藓结皮生长最好,藓结皮盖度和藓株密度均最大,分别达到了17.2%和14.6株/cm2;硫酸镁次之;用硝酸铵、磷酸二氢钾处理时,藓结皮盖度、藓株密度、藓株高与CK相比差异均不显著。2)随着葡萄糖质量浓度的增加,藓结皮盖度和藓株密度逐渐增大,且均在葡萄糖质量浓度为50 g/L时达到最大,分别为21.2%和18.9株/cm2。3)随着硝酸铵质量浓度的增加,藓结皮盖度和藓株密度呈先增加后减小的趋势,当硝酸铵质量浓度为1.0 g/L时均达到最大,分别为18.1%和16.3株/cm2。4)随着磷酸二氢钾质量浓度的增加,藓结皮盖度和藓株密度也呈先增加后减小的趋势,在磷酸二氢钾质量浓度为2.0 g/L时,藓结皮盖度和藓株密度均达到最大,磷酸二氢钾质量浓度为8.0 g/L时均降至最小。5)硫酸镁质量浓度为0.25 g/L时,藓结皮盖度和藓株密度均最大,分别达到了17.2%和14.8株/cm2。【结论】在土壤培养基中添加葡萄糖和硫酸镁可以显著提高藓结皮盖度和藓株密度;低质量浓度的硝酸铵对藓结皮的生长有促进作用,高质量浓度反而表现出抑制作用;磷酸二氢钾一次性施入培养基土壤时,其对藓结皮的形成发育没有影响;硫酸镁对藓结皮的形成发育有一定影响,但影响结果因其质量浓度不同而存在较大差异。     

毛乌素沙地苔藓结皮的野外人工培育技术

[目的]探索影响毛乌素沙地人工培育苔藓结皮的关键因子及其最优组合,为该区土地荒漠化的治理提供理论支持。[方法]利用正交试验设计方法,考虑遮阳、覆膜、营养液、浇水频率4个因子,分析不同因子对苔藓结皮株密度和生物量的影响。[结果](1)除Knop营养液外,遮阳、覆膜、浇水频率对苔藓结皮株密度、生物量有显著影响。(2)遮阳、覆膜、营养液、浇水频率4个因素对不同指标的影响顺序不同。(3)就株密度而言,野外培养最优条件为遮阳、不覆膜、Knop营养液和高频率浇水。就生物量而言,苔藓结皮野外培育最优因素组合为遮阳、覆膜、Knop营养液和高频率浇水。[结论](1)在野外苔藓结皮培育过程中遮阳、覆膜、浇水频率对结皮生长都有显著影响。(2)在提供适宜的生长条件的前提下,在干旱半干旱地区进行苔藓结皮人工培育是可行的。     

5种藓类植物水提液对黄瓜幼苗生长的影响

为研究藓类植物提取液对作物幼苗生长发育的影响,以5种藓类植物配子体不同浓度的水提液培养黄瓜种子,测定了种子萌发过程中胚芽和胚根的生长量、鲜重及干重等指标。结果表明:薄壁卷柏藓(Racopilum cuspidigerum)、疏网美喙藓(Eurhynchium laxirete)、毛枝雀尾藓(Hypopterygium trichocladon)和海岛花叶藓(Calymperes taitense)配子体的水提液在较低浓度下能提高黄瓜种子萌发的质量。其浓度为0.01g/mL时,对黄瓜幼苗的生长有明显促进作用;浓度大于0.04g/mL时,则具有抑制作用,抑制程度的大小因浓度的提高而加强。     

Study on Effects of Different Medium Compositions on Growth and Seedling Quality of Two Tomato Varieties Under Greenhouse Conditions

This research was conducted to investigate the effects of different medium compositions on physicochemical properties and the growth of two tomato varieties. Five treatments were applied, combining medium composition with rice husk ash (RHS) and coconut fiber (CF) with the following proportions: 1/3 Peat moss + 1/3 rice husk ash + 1/3 coconut fiber (T1); 1/3 Vermicompost + 1/3 rice husk ash + 1/3 coconut fiber (T2); 1/3 Cattle manure compost + 1/3 rice husk ash + 1/3 coconut fiber (T3); 1/3 Chicken manure compost + 1/3 rice husk ash + 1/3 coconut fiber (T4); 1/3 Hog manure compost + 1/3 rice husk ash + 1/3 coconut fiber (T5). The results demonstrated that between pH, electrical conductivity (EC) value, and nutrient content in the media, there was a significant difference that led to different concentrations of total macro- and micronutrients in the shoots of both varieties. In addition, the root weight, shoot weight, and root volume were affected by medium composition for two varieties in seedling stage. A mixture of cattle manures composted with RHS and CF under the rate (1:1:1 by volume), respectively, gave the highest value of germination rate, plant height, leaf number, and plant biomass. Medium composition significantly influenced the germination rate and elongation of seedlings, specifically for each tomato variety. Therefore, cattle manure compost as a medium supplement improves seedling quality and growth of the two tomato varieties.     

Peat in the inoculation medium induces fusarium susceptibility in melons

The effect of peat moss on fusarium wilt of melon ( Cucumis melo L.) was studied in order to improve the selection process of resistant melons during breeding programmes. Disease symptoms were evident earlier and disease progress was faster in seedlings that were transplanted to peat following inoculation than in those transplanted to sand. The resistant breeding line used as a control did not show any wilt symptoms in either medium. Mixing the peat with sand or perlite reduced the disease development rate and the final disease incidence. The effects of peat and sand on disease progress were evaluated with two segregating melon populations in which the expected susceptible : resistant ratio was 25 : 75. In both populations, disease incidence was higher in the peat, which enables breeders to identify resistant plants and to lower the risk of using escapees as resistant plants. The mechanism of disease enhancement may include both biotic and abiotic components. There is an indication that peat induces plant susceptibility before inoculation. Melon seedlings germinated in peat and transplanted into sand exhibited significantly greater wilt incidence than those that germinated in sand and were transplanted into sand following the inoculation. Disease progress in sterile peat was significantly slower than that in non-sterile peat, which suggests the possible involvement of microbial activity.     

荒漠刺叶墙藓DNA的提取及PCR扩增反应条件

采用改进CTAB法、NaOH法和直接PCR法(direct PCR amplification)提取藓类生物结皮中刺叶墙藓(Tortula desertorumBroth.)基因组DNA,比较其分离效果以及ISSR扩增效果。结果表明:改进CTAB法提取的基因组DNA质量好、纯度高,ISSR扩增反应效果好。直接PCR法一旦体系建立,则是最简易快速、经济高效的模板制备方法,适于植株矮小、生物量很小的荒漠藓类植物个体模板DNA的制备。利用改进CTAB法获得的基因组DNA作为模板,对ISSR反应组分浓度及反应程序中的一些重要参数进行摸索和优化实验,建立了刺叶墙藓最优ISSR反应体系。反应总体积为20μL,各反应组分终浓度为:2μL10×Buffer,2 mM Mg2 ,0.1 mM dNTPs,0.2μM引物,10~40 ng模板DNA,1U Taq酶。扩增程序为:94℃4 min,1个循环;94℃45 s,退火温度(Tm)45 s,72℃1 min,35个循环;72℃7 min,1个循环;4℃保存。刺叶墙藓是组成古尔班通古特沙漠藓类生物结皮的优势种,研究结果为进一步开展刺叶墙藓遗传多样性的研究奠定了基础。