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1.
为了探究潮汐系统下半红树植物玉蕊对盐胁迫的生理响应及其各生理指标之间的相关性,选取2年生玉蕊幼苗,采用人工模拟半日潮,在温室分别以8个不同水体盐度对玉蕊幼苗进行盐胁迫处理,研究盐胁迫对玉蕊外观形态、SOD活性、POD活性、脯氨酸含量、丙二醛含量的影响,以获得玉蕊适生的盐度范围,为玉蕊抗盐育种、栽植区域及人工造林提供理论依据。结果表明:0‰～14‰的水体盐度处理并未影响玉蕊的生长发育进程,各处理后幼苗株高和地径均有所增长,叶片数目有升有降,处理21 d后全为绿叶株,存活率100%。随着水体盐度的增高,株高总增量受到极显著影响(P 0.01),但不同盐度对地径和叶片数影响不显著。叶片SOD活性无显著变化,POD活性变化与丙二醛、脯氨酸变化一致,均随着盐度的增高整体呈显著上升趋势(P 0.01)。另外,幼苗株高与不同盐度呈极显著负相关(P 0.01),叶片脯氨酸含量与不同盐度呈极显著正相关(P 0.01),与丙二醛含量呈显著负相关(P 0.05)。综合分析可见脯氨酸、POD是玉蕊响应盐胁迫的重要指标;玉蕊的适生盐度范围是0‰～8‰,适生的临界盐浓度是10‰,盐度10‰～14‰范围表现出较好抗盐性,表明玉蕊对0‰～14‰浓度的盐胁迫具有一定的耐受性和适应性,在构建红树林湿地景观上具有良好的应用前景。  相似文献   

2.
【目的】探究小叶栎Quercus chenii Nakai苗木在NaCl胁迫下生长及生理特性的响应机制,以期为小叶栎苗木在江苏滨海地区推广栽植提供科学理论依据。【方法】选取新沂市马陵山小叶栎种质资源库2年生小叶栎容器苗为供试材料,采用容器浇盐法控制土壤含盐量,设置4个NaCl浓度梯度,分别为土壤干质量的1‰、2‰、3‰、4‰,以去离子水浇灌苗木为对照（CK）,研究不同浓度NaCl胁迫下小叶栎苗木生长及生理指标的变化情况,并通过综合分析法对其胁迫程度进行评价。【结果】小叶栎苗木体内各项生长和生理指标对NaCl胁迫均有不同程度的响应。随着NaCl胁迫浓度的增加,苗木株高增量和地径增量呈不断下降趋势,小叶栎降低苗木生长量以缓解NaCl胁迫的伤害。随着NaCl胁迫时间的延长,小叶栎苗木叶片POD活性呈下降趋势,苗木叶片相对电导率与盐害指数呈上升趋势,苗木叶片SOD活性、MDA、脯氨酸、可溶性糖和可溶性蛋白含量呈先上升后下降趋势。小叶栎苗木通过提高体内SOD、POD活性和可溶性渗透调节物质含量以提高苗木对NaCl胁迫的耐受性。【结论】根据耐盐性综合评价得出,小叶栎苗木对NaCl胁迫响应程度大小依...  相似文献   

3.
昆明市区小叶榕对冬季非节律性低温的生理反应   总被引：1，自引：0，他引：1  
将本土树种球花石楠作对照,以昆明市区行道树种小叶榕为主要研究对象,通过对其叶片5项生理指标在冬季非节律性低温发生前后的变化测定,分析其耐寒特性。测定指标显示,日最高气温由18℃骤降到4℃以及由24℃骤降到6℃时,小叶榕叶片中叶绿素含量以及叶绿素荧光Fv/Fm和Fv/Fo值均有所下降;而其叶片含水量、相对电导率和游离辅氨酸含量明显上升。综合分析表明,小叶榕比对照树种球花石楠的抗寒性弱,非节律性低温可能是昆明市区小叶榕正常越冬的主要限制性因素。  相似文献   

4.
小兴安岭典型泥炭沼泽土壤水分物理性质研究   总被引：2，自引：0，他引：2  
对小兴安岭5类典型泥炭沼泽土壤水分物理性质进行对比研究,结果表明:落叶松-杜香-泥炭藓沼泽土壤容重最小,非毛管孔隙最高,持水性最好;漂筏苔草沼泽和油桦-笃斯越桔-修氏苔草沼泽次之,修氏苔草沼泽和白桦-油桦-小叶章沼泽相对较差.落叶松-杜香-泥炭藓沼泽0～40 cm平均土壤容重为0.06g·cm-3,非毛管孔隙31.69%,总孔隙度高迭87.19%,平均土壤质量含水量、最大持水量、毛管持水量和最小持水量分别为1130.1%、1586.57%、1007.71%和882.70%,是对照林地的56.6倍、26.4倍、24.9倍和25.5倍.在5类泥炭沼泽中,白桦-油桦-小叶章沼泽0～40 cm平均土壤容重最高(0.74 g·cm-3),总孔隙度最低(62.02%),土壤各持水指标均最小,但其持水指标均显著高于对照林地.  相似文献   

5.
【目的】为了解析极小种群植物盐桦叶绿体基因组结构,筛选SSRs分子标记和桦属叶绿体基因组高变区,采用高通量测序技术完成盐桦叶绿体基因组测序并与其近缘种进行比对分析。【方法】采集盐桦幼叶,使用TIANGEN试剂盒提取DNA并利用HiSeq Xten测序平台进行测序。以欧洲矮桦叶绿体基因组作为参考,使用MITObim v1.8和NOVOplasty软件拼接组装盐桦叶绿体基因组,并利用生物信息学手段进行特征分析。【结果】利用质量控制后的30 000 000条clean data,成功拼接完成序列全长为160 648 bp的盐桦叶绿体基因组,NCBI登录号为MG674393。其中,大单拷贝(LSC)区段长度89 553 bp,GC含量33.7%,小单拷贝(SSC)区段长19 027 bp,GC含量为29.7%,2个反向重复区(IRs)区段均为26 034 bp,GC含量42.5%。成功注释了盐桦叶绿体基因组共114个基因,其中包括79个蛋白编码基因,31个tRNA基因和4个rRNA基因。盐桦叶绿体基因组含有91个SSRs位点,其中33个SSRs均由A或T组成。SSRs主要分布于LSC区,56个SSRs位于LSC区,13个SSRs位于SSC区,而IRs区有22个SSRs。对盐桦和欧洲矮桦叶绿体全基因组进行比对分析,结果显示ndhC-trnV、petA-psbJ、rpl22-rps19区域的核酸变异度(π0.2)显著高于其他区域,高变区的位置都位于LSC区,而IRs区和SSC区内2种植物变异度较小。正选择分析显示ycf1,rpoC1,rpl2与ndhA 4个基因出现正选择信号。盐桦、欧洲矮桦与其他双子叶植物共14条叶绿体全基因组序列通过MP、NJ方法进行聚类分析,MP和NJ树中的11个节点中有9个支持度为100%。支持盐桦和欧洲矮桦亲缘关系最近,桦木属物种与天目铁木在同一分支。【结论】通过高通量测序和生物信息学分析,得到盐桦叶绿体基因组。比对分析表明结构、基因组成和SSRs分布都与欧洲矮桦叶绿体基因组相似,二者在3个片段区域存在较高的核酸多态性,可作为桦属植物叶绿体基因组高分辨率的分子条形码。正选择分析确定有4个基因出现正选择信号(ycf1,rpoC1,rpl2,ndhA)。本研究结果可为极小濒危植物盐桦的保护工作提供重要的遗传背景信息。  相似文献   

6.
测定人工气候室中培养的旱柳当年生枝条和完全展开叶片的光合色素含量,并应用蔗糖密度梯度离心法提取枝条皮层和完全展开叶片叶绿体,测定其完整性,比较分析二者光响应特性和叶绿素荧光特性的差异。结果表明：旱柳皮层叶绿素含量约是叶片的10.0%,类胡萝卜素含量约是叶片的13.7%,叶绿素 a/b 比值小于叶片,叶绿素/类胡萝卜素比值大于叶片;应用蔗糖密度梯度离心法可获得被膜完整率超过80%的离体叶绿体,能够满足叶绿体光合生理特性研究的需要;100,200,300,500,800μmol·m －2 s －1光强下,旱柳皮层叶绿体的光合放氧速率均低于叶片,光饱和点出现在300μmol·m －2 s －1,最大光合放氧速率为35.58μmolO2·mg －1 Chl h －1,而叶片的光饱和点在500μmol·m －2 s －1,最大光合放氧速率为42.78μmolO2·mg －1 Chl h －1;皮层叶绿体的 PSⅡ最大光化学效率( Fv/Fm )平均高出叶片30.2%,PSⅡ潜在光化学活性(Fv/Fo)平均高出叶片36.1%。旱柳皮层叶绿体的光合速率和光饱和点低于叶片,皮层叶绿体表现出较高的光能转化效率、较低的叶绿素 a/b比值等适应枝条内光环境的特点。  相似文献   

7.
土壤微生物群落是生态功能的基础。为了揭示土壤微生物群落结构对森林湿地不同过渡带生境的响应,以小兴安岭的退化森林湿地为研究对象,沿森林至沼泽过渡带环境依次分布的4种典型沼泽湿地:白桦-落叶松(Betula platyphylla-Larix olgensis)、毛赤杨(Alnus sibirica)、油桦(Betula ovalifolia)、苔草(Carex schmidtii)分别采集0~10 cm土壤样品。采用磷脂脂肪酸(PLFAs)生物标记法分析不同过渡带土壤微生物群落结构的变化规律。结果表明:不同过渡带土壤中共检测到57种PLFA生物标记,PLFA总含量在4.06~11.06/μg/g之间,优势PLFA生物标记是16:0N ALCOHOL、16:0、18:1ω7c和16:1ω7c。土壤微生物PLFA的种类和总量沿森林至沼泽过渡带环境梯度递减,即白桦-落叶松毛赤杨油桦苔草土壤。细菌、真菌PLFA含量变化趋势与PLFA总量一致,放线菌的PLFA含量表现为白桦-落叶松油桦毛赤杨苔草土壤。土壤微生物多样性指数的Shannon-Wiener指数、Simpson丰富度指数在白桦-落叶松、油桦沼泽湿地中显著大于其他土壤,而土壤微生物的Pielou指数表现为油桦、苔草土壤显著大于其他土壤。RDA分析表明土壤有效氮含量、p H是影响土壤微生物群落的重要因子。总之,不同过渡带的土壤微生物群落结构存在差异,在监测和治理小兴安岭森林湿地生态系统时应考虑土壤微生物群落的空间分布特征。  相似文献   

8.
干旱胁迫对小叶红叶石楠光合及其他生理作用的影响   总被引：1，自引：0，他引：1  
以2年生小叶红叶石楠扦插苗为研究对象,通过盆栽控水试验,测定在不同程度的干旱胁迫下叶片相对含水量、丙二醛(MDA)含量、脯氨酸含量、可溶性糖、可溶性蛋白及光响应等生理指标,以分析其生理响应。结果表明:(1)在轻度和中度干旱胁迫下,叶片相对含水量、MDA、脯氨酸和可溶性糖含量与对照之间无显著(P0.05)差异,而可溶性蛋白含量显著低于对照(P0.05);在重度干旱胁迫下,叶片相对含水量显著下降,仅为对照的47.16%;MDA含量快速升高且显著高于对照;脯氨酸含量则急剧上升,极显著高于对照;而可溶性糖含量显著下降;可溶性蛋白含量与对照之间没有显著性差异;(2)随着干旱胁迫强度的加剧,小叶红叶石楠光合速率、光饱和点以及表观量子效应均呈下降趋势;(3)综合分析各生理指标,认为小叶红叶石楠在干旱胁迫下,通过减少叶片相对含水量,增加渗透调节物质,降低光合速率等生理响应,来抵御干旱胁迫对其的影响。  相似文献   

9.
为了提高木本蔬菜香椿的产量和质量,以湖南省湘乡市湘之椿农作物有限公司的矮化香椿为试验材料,施用不同浓度的磷酸二氢钾(KH_2PO_4)叶面肥,然后对香椿地径、老叶长度、小叶长度、小叶数量及叶片中的可溶性蛋白质、可溶性糖、氮(N)、磷(P)、钾(K)等指标进行了测定与分析。结果表明:施用不同浓度的KH_2PO_4对香椿生长及营养成分促进作用明显,浓度在0.5%~1.5%之间的叶面肥处理均能显著提高香椿的地径、老叶长度、小叶长度和数量,各指标随施肥浓度的增加均呈先升后降的趋势,但当其浓度超过2.0%时,KH_2PO_4对香椿老叶生长有抑制作用;不同浓度的KH_2PO_4对于老叶叶片中的可溶性糖、可溶性蛋白、N、P、K含量的提高均有显著效果。综合分析认为,浓度为1.0%的KH_2PO_4对香椿老叶叶片营养成分含量的提升效果最佳;KH_2PO_4处理下的香椿叶片中的N、P、K均呈现出显著正相关,且彼此之间存在一定增效作用。  相似文献   

10.
龙眼幼苗铝吸收特性的研究   总被引：4，自引：0，他引：4  
肖祥希 《林业科学》2005,41(3):43-47
铝胁迫下龙眼幼苗铝吸收特性试验表明:龙眼铝吸收特性取决于介质中铝的浓度,介质浓度≤0 3 70mmol·L- 1 时,龙眼铝吸收主要受代谢控制,属于主动吸收;介质浓度>0 3 70mmol·L- 1 时,则主要受非代谢因素影响,即为被动扩散。铝胁迫下,龙眼吸收的铝主要集中于根系,根的铝含量是茎的3 5 4～5 6 6倍,是叶片的3 .6 0～5 80倍,其积累量占全苗铝总积累量的5 8 85 %～75 0 7%,且随铝浓度的提高根中铝含量、铝积累量均大幅度增加,根吸收的铝转移到地上部的比例随介质铝浓度的提高而减小。铝在龙眼叶片细胞中主要分布在细胞壁,铝胁迫下龙眼叶片细胞壁中的铝含量占86 2 0 %～88 5 8%,依次是细胞质、叶绿体、线粒体,核蛋白中最小。  相似文献   

11.

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   

12.

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   

13.
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   

14.
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   

15.

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   

16.

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   

17.

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   

18.
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   

19.
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   

20.
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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