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1.
枣树各器官中主要矿质营养元素相关性研究 总被引：2，自引：0，他引：2
以8年生嫁接骏枣、木枣、团枣为试材,分别研究了枣树根、枝、叶、果中钾、钙、铁、锰、铜等元素的相关性。结果表明：1）与其他器官相比,3个品种枣果实中元素间相关性的正负和显著性表现较为一致,其中,钙与锰呈显著正相关;2）根、枝、叶、果中锰和铜相关系数都较大,且为正相关,骏枣的都达极显著水平。 相似文献
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不同温度、枝段部位对文冠果愈伤组织形成的效果影响 总被引：1，自引：0，他引：1
为了比较北方地区文冠果嫁接的最佳温度范围以及最佳接穗部位,特开展了不同温度、枝段部位对文冠果愈伤组织形成的效果研究,结果表明:形成愈伤组织能力按照由高到低顺序枝段部位依次为下部>中部>上部,温度依次为26℃>30℃>22℃>18℃>34℃,因此建议在我国北方地区嫁接文冠果时选择下部枝段作为接穗、温度控制在26～30℃为宜。 相似文献
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不同枣砧木1年生枝抗寒性研究 总被引：1，自引：0，他引：1
为研究枣不同砧木的抗寒性,从而为新疆枣砧木的选择提供理论依据。以收集到的6份枣砧木的1年生枝条为试材,采用人工模拟低温环境的方法对其进行低温处理,测定不同砧木的相对电导率、可溶性蛋白、可溶性糖和丙二醛含量,并应用电导法配合Logistic方程计算供试砧木的半致死温度LT_(50)。6份枣砧木的相对电导率、丙二醛含量随着胁迫温度的下降而升高,可溶性糖、可溶性蛋白含量随着胁迫温度的下降显著升高。在本实验温度处理范围内,S+灰、B+灰枝条的可溶性糖、可溶性蛋白含量均显著高于灰枣自根砧。6份枣砧木抗寒性差异较大,除毛叶枣外,LT_(50)均在-19~-24℃之间,抗寒性由强到弱依次为:酸枣、扁核酸、S+灰、B+灰、灰枣、毛叶枣。砧木嫁接可通过提高可溶性糖、可溶性蛋白含量,降低相对电导率和丙二醛含量来提高枣树的抗寒性。 相似文献
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大枣嫩枝扦插育苗技术研究 总被引：2，自引：0，他引：2
枣树为扦插难生根的树种,传统育苗为根孽育苗和嫁接育苗,育苗周期长,成本高,不能满足生产需要。利用自动间歇喷雾装置,在全光照条件下,研究了脱毒苹果枣在不同季节、不同的激素水平处理时嫩枝扦插育苗成活率。并对比了脱毒苹果枣和不脱毒的梨枣、桐柏大枣、赞皇大枣嫩枝扦插成活率差异。结果表明,脱毒苹果枣嫩枝扦插成活率明显高于其余几个品种,最高成活率97.84%;二次枝的生根率达86.31%,枣头枝生根率为73.80%,而且生长素处理对枣头枝生根率的作用要高于二次枝,使二者差异缩小,为科学选择嫩枝扦插育苗材料提供了依据。 相似文献
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枣树不同枝类次生木质部细胞解剖学研究初探 总被引：2，自引：0，他引：2
试验以骏枣、梨枣为试材，富士苹果为对照，对各供试品种不同枝类次生木质部细胞进行解离。在光学显微镜下观察分析。结果表明：骏枣、梨枣和苹果的导管细胞均为孔纹导管类型；枣的导管细胞有较厚的侧壁加厚，特别是枣股导管细胞次生壁不仅加厚明显，且细胞纹孔很小；枣与苹果之间，导管和纤维细胞的长度和直径表现极显著的差异。同一枣品种中，不同枝条及不同年龄枝条之间也表现显著的和极显著的差异；枣股的畸形细胞所占比例最多。 相似文献
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《经济林研究》2018,(4)
为了提高枸杞扦插育苗效果,采用温床处理技术对枸杞硬枝插穗生根类型、根发育起始温度和有效积温、成苗效果进行了观测和比较。结果表明,枸杞硬枝插穗生根属于皮部生根类型,根发育起始温度为11.52℃,所需有效积温为85.37 d·℃。经16、18、20、22和24℃温床处理的枸杞插穗的成苗率在87.5%～91.92%之间,处理间差异不显著,均显著高于26℃温床处理,适宜床温为16～24℃。经0、2、4、6、8和10 d 20℃温床处理的枸杞硬枝插穗成苗率分别为36.40%、59.06%、71.38%、83.92%、85.58%和90.49%,表现出随温床处理时间延长成苗率增高的趋势,充分的温床处理利于插穗成苗。 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):427-435
In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(3):206-217
The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage. 相似文献
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Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and
also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the
amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter
bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K
was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed
significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week−1 for leaves and from 0.0225 to 0.0633 week−1 for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed
during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly
between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species
provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient
enrichment capacity and slower decomposition rates which would minimize leaching losses.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(2):118-130
The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions. 相似文献
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《Wood material science & engineering》2013,8(2):76-84
Abstract Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists. 相似文献
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Steven Maranz Amadou Niang Antoine Kalinganire Djeneba Konaté Bocary Kaya 《Agroforestry Systems》2008,72(3):231-239
Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional
data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral
contents and B1 and B2 vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising
germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B1 88 mg 100 g−1, B2 187 mg 100 g−1, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal
diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties
to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations. 相似文献
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Astra Zaluma Lauma Bruna Darta Klavina Natalija Burnevica Kristine Kenigsvalde Andis Lazdins Talis Gaitnieks 《Forest Pathology》2019,49(6)
Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1):53-61
This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1):15-27
The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions. 相似文献
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本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。 相似文献