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211.
ZHANG Kai LIANG Jun ZHANG Xingyao* Research Institute of Forest Ecology Environmental Protection Chinese Academy of Forestry Beijing P.R. China 《中国林业科技(英文版)》2007,6(1):69-76
This article briefly introduced the disease incidence and disservice situation in China. The disease is regarded as cancer in pines for its higher spread and death speed and the difficulty in prevention. Strict quarantine is the main measure on countrol of the disease, for there are many difficulties in the prevention. The most important part of the disease study is the early diagnosis and detection. 相似文献
212.
ZHOU Zaohong* GUO Meifeng WUGuoxun Collegeof Resource Environment Management Jiangxi Finance EconomicsUniversity Nanchang P.R.China *Professor engaged in the urban garden green land plan the principle teaching research work.Lecturer engaged in the landscape architecture planning design teaching plant research work of the garden mainly 《中国林业科技(英文版)》2004,3(3):70-74
Native tree species plays important roles in theconstruction of urban forest. It bears manyadvantages, such as sufficient cultural context, strongecologic adaptability, high performance-cost ratio andconvenient management. The authors put forwardseveral countermeasures based on the existingproblems. And this paper will be very helpful inunderstanding why native tree species are put in animportant position in the construction of urban forest.The plant is the material basis of constructing urban… 相似文献
213.
SUN Shucun * BAO Weikai PAN Kaiwen GAO Xianming .Department of Biology Nanjing Unversity Nanjing P.R. ChinaEmail: shcs@nju.edu.cn. Chengdu Institute of Biology Chinese Academy of Sciences Chengdu P.R. China. Laboratory of Quantitative Vegetation Ecology Institute of Botany Chinese Academy of Sciences Beijing P.R. China 《中国林业科技(英文版)》2004,3(1):7-16
INTRODUCTIONMinjiangRiver,oneofprimarytributariesoftheYangtzeRiver,thatisthelongestriverinChinaandthethirdlongestintheworld,isoriginatedfromtheeasternpartofQinghai-TibetPlateauwherethegeomorphologyismainlycharacterizedbyhighmountainswithdeepvalleys(ZhangRongzu,1992).Becauseslopelandsaccountforalargeproportionofvegetatedareaandthesoillayerisverythininmostcases(ChenGuojie,2000),theupperreachesofMinjiangRiverisidentifiedtobeanunstableandfragileecosystemthatiseasilydeterioratedbyanthropog… 相似文献
214.
通过对N、P、K大量营养元素的6个不同配比试验研究,结果表明,与对照T1(N:P2O5:K2O=1:0.42:1.63)相比,T5(N:P2O5:K2O=1:0.57:1.22)配比营养液浇施,不仅能促进扦插苗地上部分的生长,还可以诱导匍匐茎的产生和膨大,从而有效提高了单株结薯率,产量增加了32.1%。由此可见,N:P2O5:K2O为1:0.57:1.22的配比是脱毒微型薯生长中所需的较为理想的营养液配方。 相似文献
215.
吐丝期干旱胁迫对玉米生理特性和物质生产的影响 总被引:10,自引:0,他引:10
以玉米品种郑单958 (抗旱性强)和陕单902 (抗旱性弱)为材料,采用抗旱池栽控水试验,研究了叶片光合特性、保护酶活性以及干物质转运对吐丝期干旱胁迫的响应。结果表明,在吐丝期干旱胁迫下2个品种产量分别降低39.10%和44.87%;叶片净光合速率(Pn)和气孔导度(Gs)显著下降,胞间CO2浓度(Ci)先升后降。PSII最大光化学效率(Fv/Fm)、实际量子产额(ΦPSII)、光化学猝灭(qP)降低,非光化学猝灭(qN)升高;抗氧化酶(SOD、POD和CAT)活性先升高后降低,而丙二醛(MDA)含量一直升高。说明吐丝期干旱胁迫增加了花前营养器官贮藏同化物转运量(率)及其对籽粒转运的贡献率;但郑单958受干旱影响程度小于陕单902。说明抗旱品种郑单958具高抗氧化酶活性清除活性氧,使得膜脂过氧化程度轻,维持较高的光化学效率,延长叶片光合功能期,促进花前营养器官贮藏同化物转运量对籽粒的贡献率。这可能是其在干旱胁迫下仍能获得较高产量的重要原因之一。 相似文献
216.
217.
Effects of cold stress on hypothalamic corticotrophin-releasing and thyrotropin-releasing hormone messenger RNA levels in chickens 总被引:1,自引:0,他引:1
WANG Jintao and XU Shiwen* College of Veterinary Medicine Northeast Agricultural University Harbin China Animal Science Veterinary Medicine Research Institute Heilongjiang Academy of Nongken Sciences Harbin China 《东北农业大学学报(英文版)》2007,14(4):327-332
There is increasing evidence that stress can activate the hypothalamic-pituitary-adrenal-axis and hypothalamic-pituitary- thyroid-axis,and further affect the synthesis and secretion of corticotrophin-releasing hormone(CRH)and thyrotropin-releasing hormone(TRH).To evaluate the effect of cold stress on the hypothalamic CRH and TRH messenger RNA(mRNA)levels in Yisha chickens,male Yisha chickens were subjected to acute(1,6,12 h)and chronic(5,10,20 d)cold stress(12±1)℃.Hypothalami were collected for assessment of mRNA levels by semi-quantitative RT-PCR.Acute stress resulted in a significant decrease of CRH mRNA levels at 6 and 12 h,and a significant increase of TRH mRNA levels at every stress time point.Chronic cold stress resulted in a significant increase of CRH mRNA levels and a significant decrease of TRH mRNA levels compared with the control group at every stress time point.The results suggest that the two genes differently respond to cold stress at the mRNA levels.And the different degrees of cold stress will produce different effects on the identical gene. 相似文献
218.
XU Qijiang CHEN Dian TONG Youli and LI Yuhua* Research Institute of Flower Biotechnology Northeast Forestry University Harbin China College of Horticulture Northeast Agricultural University Harbin China 《东北农业大学学报(英文版)》2007,14(1):9-13
Three pairs of primers were designed and synthesized from nucleotide sequences of garlic latent virus (GLV), onion yellow dwarf virus (OYDV), and leek yellow stripe virus (LYSV) by using PCR primer design software. The expected fragments about 170 bp, 287 bp, and 191 bp were amplified by RT-PCR for GLV, OYDV, and LYSV, respectively in disease-infected plants of potato onion (Allium cepa L., Aggregatum group), but such fragments were not obtained from healthy-looking plants and virus-free seedlings of shoot-tips. The amplified products of GLV, OYDV and LYSV were cloned into pGEM-T vectors, and transformed into Escherichia coli. JM109. The recombinant plasmids were obtained and sequenced. The nucleotide sequences were compared with corresponding viral nucleotide sequences reported in GenBank by performing a NCBI BLAST. The analysis showed that their homology attained 75% to 90%,89.5% to 96.1%,and 91.6% to 96.3% in GLV, OYDV, and LYSV, respectively. The total RNA of 6.34 μg·μL~(-1) from infected plants was diluted to a series of 10~(-1) to 10~(-5) and the detection sensitivity of RT-PCR was 10~(-4) (about 4 ng). Thus, a method of identification and detection by RT-PCR of GLV, OYDV, and SLYV was established. 相似文献
219.
220.
农杆菌介导的橡胶树遗传转化影响因子 总被引:1,自引:0,他引:1
论述和分析了影响农杆菌介导橡胶树遗传转化的主要因子,包括橡胶树植物基因型、农杆菌菌株、菌液浓度、培养基附加成分等内外因子,简要概述并对其存在的问题和应用前景。 相似文献