Influence of N fertilisation on the isolation of Acetobacter diazotrophicus and Herbaspirillum spp. from Indian sugarcane varieties

 Observations of newer diazotrophs like Acetobacter diazotrophicus and Herbaspirillum spp. in Indian sugarcane varieties is reported here for the first time. A. diazotrophicus was isolated from sugarcane plants where N fertilisation was nil, and numbers in the Indian cultivars were estimated to be up to 10⁶–10⁷ colony forming units g¹ fresh weight. N fertilisation was the limiting factor for the isolation of A. diazotrophicus, as evidenced by selective growth patterns in different concentrations of N sources, but Herbaspirillum spp. were found to occur both in N fertilised and unfertilised samples. The fact that N is not the limiting factor for Herbaspirillum spp. was evidenced in a similar study of its growth pattern in different N sources. Received: 14 May 1998     

热水处理对3种进口苗木的损伤及抗氧化酶系的影响

为了探明热水浸泡处理对进口南洋参、香龙血树和百合苗木的影响,本试验分别利用45℃60min、48℃10 min、48℃30 min和48℃60 min,4组时间和温度组合对3种进口苗木进行热水浸泡处理,然后测定处理后各供试苗木叶片中丙二醛(MDA)含量,过氧化物酶(POD)活性、过氧化氢酶(CAT)活性和超氧化物歧化酶(SOD)活性。而后对处理后各供试苗木进行复种,3周后观察复种苗木的生长情况。结果表明:3种供试苗木各处理组MDA含量均比对照组有所增加;POD活性仅有南洋参部分处理组比对照组有所增加,南洋参其他处理组以及香龙血树和百合各处理组均比对照组有明显下降;CAT活性南洋参和香龙血树各处理组与对照组之间均差异不显著,百合各处理组均比对照组有所增加;SOD活性百合各处理组相比对照组均出现了明显的下降。经过热水浸泡处理后复种的各供试苗木,南洋参和香龙血树均能够正常生长,百合均死亡。上述研究表明南洋参和香龙血树对热耐受性较高,可利用热水浸泡进行检疫除害处理,百合耐受性较差,不能采用热水浸泡进行检疫除害处理。     

利用均匀设计法优化鸡(土从)母种培养基

鸡(土从)菌丝生长缓慢,在培养过程中极易被污染,为了提高鸡地从菌丝生长速度,减少被污染的机率,在前期单因素试验筛选鸡(土从)母种培养基中的碳源、氮源、氨基酸、维生素、无机盐、蚁穴浸提物、抑菌剂等结果的基础上,选取马铃薯汁、麦芽糖、酵母膏、VB_9、脯氨酸、可溶性碳酸钙清液、磷酸二氢钾、硫酸镁、蚁穴浸液、链霉素等10个因子,每个因子设12个水平,采用U₁₂(12¹⁰)均匀设计表设计试验方案,对鸡(土从)母种培养基进行优化。最优母种培养基配方为马铃薯汁126.20 mL·L^-1、麦芽糖11.63 g·L^-1、酵母膏5.50 g·L^-1、VB_9 47.90μg·L^-1、脯氨酸23.37μg·L^-1、可溶性碳酸钙清液0、磷酸二氢钾0.07 g·L^-1、硫酸镁4.19 g·L^-1、蚁穴浸提物61.82 mL·L^-1、链霉素2.33 mg·L^-1。利用该优化配方的培养基培养的鸡(土从)母种,其菌丝生长速度快,长势强。     

粘帚霉不同菌株发酵液对3种病原真菌的抑制作用

试验测定了8个粘帚霉Gliocladium spp．菌株的发酵液对3种重要土传病原真菌尖孢镰刀菌Fusarium oxysporum Schlecht．、立枯丝核菌Rhizoctonia solani和核盘菌Sclerotima sclerotiorum的抑菌效果。结果表明,HL-1-1、SH-1-1和SS-1-1的抑菌作用最强,抑菌率分别达83．48％、81．65％和78．68％,3个菌株之间差异不显著;SDT-lO-1的抑菌作用最小,抑菌率仅为23．24％。热稳定性测定结果表明：发酵液121℃处理30min,病原菌生长正常,抑菌作用消失;发酵液经60℃处理后供试菌株的抑菌效果明显,但效果明显降低。     

几种拟青霉脂溶性组分的初步研究与应用

Paecilomyces is a genus closely related toPenicillium. Most species of Paecilomyces arecommon soilborne saprobes, a section in this genusis known primarily as parasites of insects. Somespecies of another section are quite tolerant of hightemperatures.     

Acacia plantations in Indonesia facilitate clonal spread of the root pathogen Ganoderma philippii

Ganoderma philippii is a root pathogen of many woody plants in tropical regions and is particularly aggressive to Acacia mangium, which is grown on a 6-year rotation for pulpwood in Indonesia. The disease becomes progressively worse over each rotation and control measures have met with limited success. We studied the population genetics of G. philippii to evaluate the role of sexual and asexual reproduction in its mode of spread. Populations were genetically distinct with high levels of inbreeding, and clonal spread to adjacent trees increased after the first rotation. Despite the high levels of genetic diversity seen at all sampling scales, migration rates appear low. Measures to reduce the underground spread of the pathogen as well as methods to prevent the initiation of new infections from basidiospores will be needed to reduce the incidence of root rot in A. mangium plantations.     

施肥对桉树幼林生长量的影响

通过正交试验设计探索施用不同种类肥料、不同施肥方法对不同家系桉树幼林生长量的影响差异,结果表明:在福建省闽南海拔700 m以下丘陵山地以尾细桉M1(A3)+0.3 kg.株-1(分2次施)磷酸二铵(B1)+开放射沟施的方法(C3)最好,1 a高生长量达7.3 m、胸径达4.2 cm。     

相思树硫酸盐浆无元素氯漂白性能的研究

系统对比研究了大叶相思、马占相思、厚荚相思及纹荚相思4种相思树硫酸盐法制浆性能及无元素氯(ECF)漂白性能。结果表明,采用硫酸盐法制浆,用碱量(氧化钠计)16%、硫化度25%时,制得的4种相思树硫酸盐浆经OPDP1P2(OP为氧强化脱木质素,D为ClO2漂,P为H2O2漂)4段漂白,漂后纸浆的光学性能及强度性能优良。纸浆白度均达86.0%(ISO,以下同)以上,叩解度为30°SR时,抗张指数在55.8~60.7N·m/g之间。4种相思树中大叶相思的制浆性能最优,马占相思和纹荚相思居中,厚荚相思的制浆性能最差。     

福建东南沿海丘陵山地相思类树种造林选择研究

针对福建东南沿海丘陵山地适生树种稀少的现状，开展了相思类树种的引种造林试验。10a试验结果表明，厚荚相思、马占相思和大叶相思在沿海丘陵山地引种保存率高、生长快、适应性强，3种相思对贫瘠土壤理化性质的改良作用明显，这3种相思是沿海丘陵山地较为理想的造林改土树种。