稀有植物喜荫草种群结构及所在群落结构特征

文章对我国热带地区出现的稀有植物喜荫草S.tenella Bl.的种群结构及其所在群落结构特征进行描述。结果表明喜荫草在野外出现的频度较小,不易于被发现;但其种群结构较为稳定,更新良好。而且,喜荫草种群所在群落存在一定数量的本土特有种和保护植物,喜荫草能与它们良好的共生,它主要生长区域集中在尖峰岭自然保护区的范围内,得到良好的保护。     

The pH change in rhizosphere ofPinus koraiensis seedlings as affected by different nitrogen sources and its effect on phosphorus availability

Root mat method described by Kuchenbuch and Jungk was used to study the rhizosphere processes. The experiment was carried out on two years oldPinus koraiensis seedlings. Soil samples collected from the upper 20-cm soil layer in Changbai Mountain were treated with three different forms of nitrogen fertilizers: NO₃ ⁻−N, NH₄ ⁺−N and NH₄NO₃. The results showed that the soil pH and available P near the roots were all lower than in the bulk soil in control treatment. NH₄ ⁺−N application greatly decreased the soil pH near the roots compared to the control treatment and promoted the absorption of phosphorus, which led to a more remarkable depletion region of available P. On the contrary, the rhizosphere soil pH was higher than in the bulk soil in treatments with NO₃ ⁻−N and retarded the P absorption, which led to a nearly equal available P contents to the bulk soil. In treatment with NH₄NO₃, the rhizosphere soil pH was only a little lower than that in the control treatment and its effects on P absorption is mediate between the treatments with NH₄ ⁺−N and NO₃ ⁻−N. Foundation item: This paper was supported by National Natural Science Foundation of China (Grant No. 30170167). Biography: Chen Yong-liang (1969-), male, Ph. Doctor, lecture of Northeast Forestry University, Harbin 150040, Post-doctor in Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P.R. China. E-mail: ylchin@sohu.com Responsible editor: Seng Funan     

单杆芦荟离体快速繁殖技术研究

单杆芦荟离体快速繁殖，芽增殖培养基以MS＋BA2．5mg/L NAA0.2-0.3mg/L，生根培养基以1／2MS＋NAA 2.0mg/L 活性炭0．2％－0．3％，壮苗培养基以1／2MS＋IBA2.0mg/L为好。培养温度以28℃最佳。快速繁殖方法用分叶法比常用的分株、分芽方法，繁殖系数高。培养出的壮苗移栽于河沙中，成活率一般在80％以上。     

管氏肿腿蜂防治双条杉天牛的应用技术

管氏肿腿蜂 Scleroderma guani Xiao et Wu防治双条杉天牛在北京地区最适放蜂时间为 5月下旬至 6月上旬 ,虫蜂数量比为 1∶ 3～ 1∶ 6。化学农药对蜂的杀伤力大于植物性农药     

浑善达克沙地复合式固沙造林技术分析

复合式造林技术 ,实施后形成带、网、片 ,乔、灌 ,针、阔混交复合式格局 ,变一般固沙型式所形成的单一脆弱植物结构 ,为多样性生物群落 ,使防沙治沙效益向更高层次发展。     

Comparative analyses on the litter in Korean pine Mongolian Scots pine and Dahurian Larch plantations

Comparative analyses were conducted on the nutrient element content and returning amount of main fractional compositions of litter in Korean pine (KP), Mongolian Scots pine (MSP) and Dahurian larch (DL) plantations in Laoshan Plantation Experiment Station of Maoershan Experiment Forest Farm of Northeast Forestry University. The results are as follows: (1) The nutrient element content and returning amount in litter varies among different fractional compositions and tree species, the total returning amount of all nutrient elements and the returning amount of K, Ca, Mg, N and P are DL > MSP > KP, the returning amount of Cu is DL > KP > MSP, the returning amount of Fe and Mn are MSP > DL > KP; (2) To KP and DL plantations, the main nutrient element returned is dead needles; dead branches, bark scales and dead cones account for a little proportion; whereas to MSP plantation, besides dead needles, dead branches and bark scales also play an important role in the return of nutrient elements; (3) A little deal of dead leaves can provided a great deal of returning amount of nutrient elements.     

液培杉木苗根系分泌性能的初步研究

对１年生杉木苗培养液的ｐＨ、电导率和有机碳含量的测定表明：经过杉木苗培养后的各营养液的ｐＨ均有下降趋势，其中以硝态氮营养液下降幅度最大（下降１．７２），其次是缺锌营养液（下降１．６８），最小为缺磷营养液。各种营养液的电导率变化较复杂，缺磷、缺锌和对照处理电导率增大，而硝态氮、混合氮和缺铁处理下降。杉木苗分泌有机碳以对照组最多，缺铁培养的分泌最少。     

适应山区发展的美国布朗李的引种栽培

美国布郎李的两个品种－紫琥珀和黑宝石从１９９２年引入金华以来，表现出来的丰产稳产状，适应性强，品质佳等特点深当地群众喜爱，概述了这两个品种的生态生产物学特性及引种几个来的生长结果状况后，进而对它们的引种栽培技术作了介绍。     

切根、截顶对湿地松裸根苗生长调控效果的研究

在江西景德镇和安徽泾县布置了１年生湿地松裸根苗生长后期切和截顶试验，研究其对苗木形态和造林表现的效应及其例题应用制度。两年的结果表明，切根苗的高、径及主根形态指标均低于未切根苗，而侧须根系增加，早切根多次切根处理效应最显著。     

灵芝适生树种

本文列举了７７种灵芝适生树种，分属２０科４２属，其中常用树种主要属于壳斗科、杜英科、金缕梅科；段木栽培效果比较理想的树种是福建山樱花（野樱），并介绍了芝树的选伐及段木的熟化处理。