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91.
银木(Cinnamomum septentrionale Hand.Mazz.)系樟科樟属的常绿乔木,主要分布在年平均气温14℃,降水量800 mm以上的四川、陕西南部、甘肃南部、湖南等地区,是自然分布最北面的樟科植物.该树种系典型的北亚热带树种,对水、热条件的要求低于其它樟科植物,既能耐-10℃的低温,又能耐干旱[1].银木树皮灰色、光滑,叶近革质,互生,椭圆状、倒圆状披针形,具有较好的观赏性和较高的开发价值,在湖南、四川等地已人工栽培多年,形成特色鲜明的城市行道树. 相似文献
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不同种源翅荚木的抗寒性 总被引:8,自引:0,他引:8
以5个种源的翅荚木叶为材料,采用叶片离析法和石蜡制片技术观测叶片结构特征、电导率法测定其半致死温度、差示热量扫描仪测定其过冷点温度,并结合田间试验分析不同种源翅荚木苗期的抗寒性及其与叶片结构的关系.结果表明:湖南通道翅荚木种源抗寒性最强,苗期在湖南株洲无冻害,在浙江丽水冻害率为4.83%,极显著低于其他种源;其叶片半致死温度为-5.34 ℃,过冷点温度为-15.04 ℃,均低于广东翁源和广西忻城种源. 不同种源翅荚木叶片细胞结构紧密度(CTR)和疏松度(SR)与种源的抗寒性有一定的关系,CTR值越大、SR值越小,种源的抗寒性越强. 相似文献
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在低温锻炼和结合蔗糖处理的低温锻炼下 ,对毛白杨 (Populustomentosa)幼苗枝条和叶片的可溶性糖含量 ,以及幼苗存活率和抗冻性分别进行了测定 .结果表明 ,低温锻炼明显提高了幼苗枝条和叶片的可溶性糖含量 ,同时也提高了幼苗的存活率和抗冻性 .2 0 %蔗糖处理对上述低温锻炼的作用有加强的效果 .进一步分析发现 ,无论是单纯的低温锻炼还是结合蔗糖预处理的低温锻炼 ,幼苗枝条中可溶性糖含量的提高程度均较叶片明显 ,而且它们的含量增加与幼苗抗冻性的提高密切相关 .这表明低温锻炼所引起的可溶性糖积累可能参与了幼苗抗冻性的诱导 相似文献
96.
Dai Huanqin Lu Cunfu* Zhang Hui Zhang Xujia College of Biological Sciences Biotechnology Beijing Forestry University Beijing P. R. China Institute of Biophysics Chinese Academy of Sciences Beijing P. R. China 《中国林学(英文版)》2003,5(4)
Populus euphratica Olive is the only tree species that can grow in the saline land and also survive cold winters in northwest China, and it plays a very important role in stabilizing the vulnerable ecosystem there. A cell suspension culture was initiated from callus derived from plantlets of Populus euphratica. Cold acclimation was induced (LT50 of-17.5 ℃) in cell suspension at 4-5 ℃ in the dark for 30 days and the freezing tolerance increased from LT50 of-12.5 ℃ in nonacclimated cells to LT50 of-17.5 ℃ in cold-acclimated cells. Microvacuolation, cytoplasmic augmentation and accumulation of starch granules were observed in cells that were cold-acclimated by exposure to low temperatures. Several qualitative and quantitative changes in proteins were noted during cold acclimation. Antibodies to carrot extracellular (apoplastic) 36 kD antifreeze protein did not cross react on immunoelectroblots with extracellular proteins in cell suspension culture medium of Populus euphratica, indicating no common epitopes in the carrot 36 kD antifreeze protein and P euphratica extracellular proteins. The relationship of these changes to cold acclimation in Populus euphratica cell cultures was discussed. 相似文献
97.
青檀耐荫性的初步研究 总被引:15,自引:0,他引:15
在连续3年测定比较几个不同树种的生理特性和树冠结构的基础上,本文对青檀的耐荫性进行了初步分析,结果表明,青檀的耐荫性随年龄的增大而降低,12年生以前,青檀是耐荫的;13至25年生之间,青檀是喜光树种;26年生以后青檀则逐渐变为阳性树种。比较的结果还表明,青檀的耐荫性较马尾松强,较杉木弱,从总体看属中偏阳树种。 相似文献
98.
田间和盆栽核桃与柿子苗木光合特性的初步研究 总被引:3,自引:0,他引:3
研究了核桃(Juglans regia L.)、柿子(Diospyros kaki L.f.)两种苗木在田间和盆栽栽培条件下的光合特性。通过室内人工控制光强和CO2浓度,测得盆栽的核桃、柿子的光补偿点分别是62 μmol CO2/m2·s、40μmol CO2/ m2·s;饱和点分别是1 582 μmol CO2/m2·s、1 064 μmol CO2/m2·s;CO2补偿点分别是135 ml/L、230 ml/L。6月的晴天,核桃、柿子盆栽栽培中的净光和速率日变化呈"双峰"型;田问栽培中仅出现1次高峰。两种栽培均出现"午休"现象。 相似文献
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100.
Geographic Information System‐Based Analysis of the Spatial and Spatio‐Temporal Distribution of Zoonotic Cutaneous Leishmaniasis in Golestan Province,North‐East of Iran 下载免费PDF全文
Zoonotic cutaneous leishmaniasis (ZCL), a vector‐borne disease, poses serious psychological as well as social and economic burden to many rural areas of Iran. The main objectives of this study were to analyse yearly spatial distribution and the possible spatial and spatio‐temporal clusters of the disease to better understand spatio‐temporal epidemiological aspects of ZCL in rural areas of an endemic province, located in north‐east of Iran. Cross‐sectional survey was performed on 2983 recorded cases during the period of 2010–2012 at village level throughout the study area. Global clustering methods including the average nearest‐neighbour distance, Moran's I, general G indices and Ripley's K‐function were applied to investigate the annual spatial distribution of the existing point patterns. Presence of spatial and spatio‐temporal clusters was investigated using the spatial and space–time scan statistics. For each year, semivariogram analysis and all global clustering methods indicated meaningful persistent spatial autocorrelation and highly clustered distribution of ZCL, respectively. Eight significant spatial clusters, mainly located in north and northeast of the province, and one space–time cluster, observed in northern part of the province and during the period of September 2010–November 2010, were detected. Comparison of the location of ZCL clusters with environmental conditions of the study area showed that 97.8% of cases in clusters were located at low altitudes below 725 m above sea level with predominantly arid and semi‐arid climates and poor socio‐economic conditions. The identified clusters highlight high‐risk areas requiring special plans and resources for more close monitoring and control of the disease. 相似文献