黄帝陵古侧柏死亡原因调查

黄帝陵古侧柏林由于人为破坏,管理不善,环境污染等原因致使生长不良。在此基础上,由于侧柏大蚜、侧柏毒蛾、明纹侧柏松毛虫、柏肤小蠹和双条杉天牛等害虫连续相继危害,致使生长衰弱的侧柏局部枝条或整株死亡。     

大豆花叶病毒病流行模拟和防治决策模型SIMSMV

大豆花叶病毒（SMV）流行和防治的模拟系统SIMSMV是由大豆生长、病害日侵染率、显症率、种子传毒率、种子褐斑率、产量损失6个子模型和播种种子带毒率允许水平及介体蚜虫防治模型所构成。本模型只需输入几个简单的初始变量即可实现对SMV流行、危害的模拟及制定病毒防治决策。经过三年的检验和试用,证明本模型系统结构合理、模拟准确、决策可靠。     

Cryopreservation of in vitro-grown meristems of strawberry (Fragaria × ananassa Duch.) by encapsulation-vitrification

Alginate-coated meristems from in vitro-grown strawberry (Fragaria × ananassa Duch.) were successfully cryopreserved following dehydration by a vitrification solution. Excised meristems from cold-hardened plantlets at 4 °C for two weeks in the dark were encapsulated into alginate-gel beads containing a mixture of 2 M glycerol plus 0.4 M sucrose. These encapsulated and cryoprotected meristems were dehydrated with a highly concentrated vitrification solution (designated PVS2) for 2 hr at 0 °C prior to a plunge into liquid nitrogen. Successfully encapsulated vitrified meristems remained green and then developed shoots within one week after plating without intermediary callus formation. The average rate of shoot formation of encapsulated vitrified meristems amounted to nearly 90%. The cryogenic protocol was successfully applied to four cultivars of strawberry. It was also confirmed that encapsulated vitrified meristems cooled to - 196 °C produced higher shoot formation than encapsulated dried meristems. Besides, the recovery growth was much earlier than the latter. The encapsulation-vitrification method is easy to handle and produces high levels of shoot formation. Thus, the protocol promises for cryopreservation of strawberry germplasm. This revised version was published online in July 2006 with corrections to the Cover Date.     

玉米原生质体培养及可育植株的再生

由玉米获白×莱1029的幼胚诱导愈伤组织,经改造后进行液体悬浮培养,获得了优良的、有再生能力的悬浮细胞系。用其分离原生质体,采用4种方式进行培养,最高原生质体植板率达到1.2％。原生质体再生的小愈伤组织,通过分步诱导分化法,获得了5株完整的绿色植株,经进一步的壮苗培养后,移栽到土壤中全部成活,最终雄穗结籽。后代植株育性正常。     

云南省怒江峡谷区桐农复合经营模式效益分析

通过云南省怒江峡谷区桐粮间作试验,对油桐和间作作物的生长、产量等进行了观测与分析。结果表明,桐农复合经营投资少,见效快,可操作性强,综合效益好,好在该类山区农村大力推广。     

Heterobasidion annosum group S identified in north-eastern China

Samples of Heterobasidion annosum were collected in two stands of mixed forest in Changbaishan Nature Reserve in north-eastern China. Pure cultures were isolated from 15 specimens growing on Abies, Picea, Pinus and Populus. Mating tests showed that all these collections belong to the S inter-sterility group. The compatibility of Chinese homokaryons with S homokaryons from Europe was 100%. Clamp connections appeared almost equally in both strains of each pairing, and no distinct demarcation line formed in the pairings. The mating frequency of Chinese isolates with the European F group was also high, approximately 94%. These matings, however, were usually unilateral and a more or less distinct demarcation line was present in most of the pairings. The Chinese isolates were completely intersterile with the European P group. The S group of H. annosum in north-eastern China appears to have similar morphology and ecology as in Europe. It is common on Abies and Picea, but is not a serious pathogen in the pristine forests of north-eastern China.     

南洞庭湖滨湖区农田防护林体系的结构和效益评价

在分析南洞庭湖滨湖区农田防护林体系结构的基础上,评价其生态效益、经济效益和社会效益,并探讨对于湿地保护的重要性．认为发展滨湖区林业应有利于维护湿地生态平衡,把重点放在优化和完善防护林体系的结构上,并提出了滨湖区农田防护林体系的建设原则,以及林带结构优化和林带、林网改造的具体方法．     

七种高香型乌龙茶香气成分的主成分分析

用主成分分析法对７种高香乌龙茶的主要香气成分进行了分析。结果表明：各香型茶皆有较为突出的赋香物质存在,这些物质的不同组合,形成了各自的香气特征。文章中列出肉桂香茶,玉兰香茶,黄枝香茶,芝兰香茶名香气成分组合的表达式。     

黄山松群体酶基因遗传变异的研究

应用等位酶分析法,分析了１８个林分群体（小群体）２８０多株黄山松种子胚乳的ＥＳＴ和ＭＤＨ酶的酶基因。结果表明：ＥＳＴ酶受３个基因位点调控,其中２个位占 有等位基因５个、４个,平均为３．５８个;ＭＤＨ酶受４个基因位点调控,其中３个位点各有等位基因３个、５个、５个,平均为２．８１个。基因位点均是多态的。等位基因在群体中的分布不同。ＥＳＴ酶基因位点的平均期望杂合度为０．５６２,ＭＤＨ酶基因位点的平均期望