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1.
毛乌素沙地巴图塔沙柳沙障对植被恢复作用的研究   总被引：10，自引：0，他引：10  
以毛乌素沙地巴图塔沙柳基地为研究区域,采用野外调查和统计分析相结合的方法,对沙障设置前后的植被动态变化、物种多样性进行研究,进而分析沙柳沙障对植被恢复的影响。研究结果表明:随着沙障设置年限的增加,群落的物种数增加;群落类型由沙障设置前的沙米+沙竹群落发展成沙柳人工植被群落,在演替过程中无物种消失,物种多样性与沙障设置年限基本呈正相关关系。证明流动沙丘上植被恢复过程中沙柳沙障起着重要促进作用。  相似文献   

2.
科尔沁沙地植物再生沙障人工群落结构特征   总被引：2，自引：0，他引：2  
 采用时空替代法,对科尔沁沙地黄柳(Salix gordejevii)+杨柴(Hedysarum leave)植物再生沙障人工群落的结构特征进行研究。结果表明:1)利用植物再生沙障治理流动沙丘可以形成具有多物种、多层片、多层次垂直结构的沙障群落,其水平结构呈网格状沙障结构与障间小群落在空间上镶嵌互补,均衡分布的格局,具有很好的防风固沙和植被恢复效果;2)再生沙障建植后第5年开始,沙障群落进入了衰退时期,适时采取科学的经营管理措施对于维持沙障群落的稳定,保障其效益的长期发挥是非常重要的。  相似文献   

3.
选择设置了12年的塑料网格沙障、麦草沙障和黏土沙障进行长期定位观测,以流动沙丘作为对照,对机械沙障内的植被、土壤机械组成及土壤水分特征进行研究,结果表明:机械沙障内的植被盖度显著增加,多样性指数麦草沙障和黏土沙障显著增加、塑料网格沙障减小,群落结构由耐旱植物向短命植物演替;不同的机械沙障均能增加表层土壤中的黏粒含量,但塑料网格沙障与黏土沙障内土壤的黏粒含量增加显著,麦草沙障增加不显著;不同机械沙障的建立均使得土壤的含水量下降,塑料网格沙障、麦草沙障和黏土沙障内的土壤含水量比流动沙丘分别降低了41.29%、5.05%、31.78%,沙障内土壤水分的季节性变化更加稳定;受机械沙障的影响,降水的入渗深度及入渗速率均减小,使得土壤水分的再分配过程产生明显的滞后性。机械沙障设置后期虽然引起土壤水分含量减少,但它带来的防风固沙效益不容忽视。综合考虑其成本、效益及时效性等因素,认为在沙区应该推广塑料网格沙障。  相似文献   

4.
古田山国家级自然保护区甜槠群落物种多样性研究   总被引：3，自引：0，他引：3  
研究分析浙江古田山国家级自然保护区甜槠群落植物区系组成和物种多样性结果表明 ,该区甜槠群落共有维管束植物 4 9科 86属 133种 (含变种 ) ,其中蕨类植物 4科 5属 6种 ,裸子植物 2科 2属 2种 ,被子植物 4 3科 79属 12 5种。植物区系成分复杂 ,热带成分比例较高。甜槠群落科、属、种组成多样性较高 ,植物种类丰富且组分复杂 ,群落垂直结构中灌木层乔木层草本层物种多样性依次递减 ,乔木层、灌木层物种丰富度与多样性指数明显大于草本层。  相似文献   

5.
城市化进程中撂荒地植被恢复方式对植物多样性的影响   总被引：1，自引：0，他引：1  
通过野外调查,研究鄱阳湖生态经济区城市化进程中农田生态系统撂荒后,自然更新和人工更新2种方式下的植物多样性和群落物种结构.结果表明：1）在撂荒地共发现42种植物,隶属22科42属,其中自然更新群落样地有10科20属,人工更新群落样地有19科34属;2）2个群落的科、属、种数在统计上差异不显著,只表现出人工更新群落稍高于自然更新群落,植物丰富度、多样性指数在统计上差异不显著,但是呈上升趋势;3）自然更新和人工更新2个群落间的植物种相似系数为0.44,自然更新和人工更新2个群落中的共有植物种类为12种,以一年生草本居多;4）应用除趋势对应分析排序方法（DCA）分析表明,2个群落结构间已形成梯度,在人工更新群落增加了多年生草本、多年生草质藤本和小灌木,人工更新减缓了植物多样性丧失的速度.在城市化圈地过程中,建议在撂荒期栽植乔木树种,有利于生物多样性的保护.  相似文献   

6.
对深圳莲花山植被组成及多样性进行了调查研究,5个植物群落共有67科、128属和166种。可见其科的数量较多,每个属所拥有的种也较少,表现出此区域植被组成的遗传差异较高。各群落在种类α-多样性D_s、H、丰富度R_1、R_2及均匀度J值的大致的顺序为群落3和4最高和次高,群落5最低;而群落3和4为自然恢复和半自然恢复的林地,其他3群落为人为干扰较多的群落,其中,群落1受到人为干扰明显强,群落5为较明显的人工林地。因此,对于究竟是人为干扰的群落还是自然恢复的林地群落植物多样性高的争论而言是一个很好的佐证和参考。科的多样性指数D_f值顺序表现为群落5和3的多样性最高,而群落2处在中间地位,群落4最低。属的多样性指数D_g值表现为群落5和3较高,群落1最低。同时表现出各群落里科的多样性较高,而属的多样性较低;在综合多样性系数D_c值方面,其大小顺序为:群落3群落4群落2群落5群落1。表明2个处在自然和半自然恢复的植物群落其科、属和种的多样性比受到不同程度人工干扰的3个群落的多样性高。在α-多样性方面,与深圳其他山地和部分公园的植物多样性相比,莲花山的植物种类多样性基本处于中等水平,但在各群落内的灌木层及草本植物方面显得比其他地区的明显高。与部分其他国家的山地植物群落的植物物种多样性相比,则基本处在偏高的水平,说明深圳莲花山的植物物种等级的多样性整体处于中等偏高的状态。而在各群落之间科、属的β-多样性系数方面,莲花山各群落之间的系数值都明显高于其他区域的山地自然群落,而比少部分人为干扰较多或者人工经济林的偏低。说明其整个区域的科及属的多样性还是处在偏低的水平。  相似文献   

7.
宝天曼自然保护区栓皮栎林人工恢复与天然恢复效果比较   总被引：1，自引：0，他引：1  
为比较宝天曼自然保护区内栓皮栎林人工恢复天然恢复的差异,采用样地调查法对相同恢复年限的栓皮栎人工林与天然次生林的物种组成、重要值、多样性指数和土壤性质等群落特征指标进行了比较研究。结果表明:(1)栓皮栎人工林群落具有维管束植物12科18属24种,次生林群落具有维管束植物27科40属48种,两个群落相似性较低(0.36);(2)栓皮栎次生林乔木层和灌木层物种的重要值比人工林低,乔木层和灌木层的物种数较人工林多;(3)栓皮栎人工林与次生林群落的乔木层、灌木层和草本层的Maglef指数、Shannon-Wiener指数、Simpson和Pielou均匀度指数相比均较低,人工林的4个多样性指数大小依次为灌木层、草本层、乔木层,天然次生林指数大小表现依次为灌木层、乔木层、草本层;(4)栓皮栎次生林的土壤全氮、全磷、有机质含量比人工林均较高。研究表明在宝天曼自然保护区内,相同恢复的年限,栓皮栎天然次生林无论物种组成、多样性指数、群落结构和土壤理化性质均优于栓皮栎人工林,天然恢复比人工造林恢复效果好。  相似文献   

8.
浙江省废弃采石矿区植被重建后物种多样性研究   总被引：2，自引：0，他引：2  
选取5个物种多样性指数,对浙江省40个养护期内的废弃采石矿区的物种多样性进行了研究,结果表明,(1)浙江废弃采石矿区内植物种类较多,科属组成较为分散.从群落结构组成来看,草本植物为优势群体,草本植物引导种以豆科类植物和禾本科类植物居多.(2)革本、灌木和乔木植物群落丰富度指数和物种多样性指数都表现出一致的变化趋势,草本植物群落的这些指数值明显高于灌木和乔木植物群落,草本、灌木和乔木植物群落的群落均匀度指数都较高.(3)浙江省废弃采石矿区内草本植物乡土物种占主导地位,其中以菊科类植物居多.  相似文献   

9.
[目的]对内蒙古境内浑善达克沙地植被恢复过程中植物群落的物种组成以及多样性的变化规律进行分析,为该地区的植被恢复提供理论依据和科学指导。[方法]采用样带法对植物群落进行调查。[结果](1)沙地植被恢复5年后群落内共有33种植物,分属于10科27属;(2)随着恢复年限的延长,物种丰富度指数、物种多样性指数、物种均匀度指数和群落盖度均逐渐增大,而生态优势度指数则逐渐减小。植物群落物种由6种(未治理)增加到21种(治理5a),物种多样性指数由1.20增加至2.77,物种均匀度指数由0.67升高至0.91,群落盖度从2.06%增加到75.58%,生态优势度指数由0.57减少至0.32。[结论]浑善达克沙地飞播区植被得到明显恢复,沙地恢复到一定阶段后群落趋于稳定,风沙化得到一定程度的遏制。  相似文献   

10.
河西走廊中部人工沙漠植被典型群落物种的多样性   总被引：2，自引：1，他引：1  
[目的]揭示河西走廊中部人工沙漠植被典型群落物种多样性研究,为干旱沙漠地区的生态恢复和人工植被建设及沙区植被多样性的恢复与重建提供理论依据。[方法]基于对甘肃省张掖市临泽县治沙站人工沙漠典型群落物种多样性进行调查。运用Simpson和Shannon-Wiener物种多样性指数,Margalef物种丰富度指数,Simpson物种优势度指数和Pielou物种均匀度指数计算。[结果]灌木群落具有较高的丰富度指数和多样性指数,而草本群落具有较高的均匀度指数;物种多样性指数、丰富度指数变化趋势基本一致,而均匀度指数则呈相反趋势;β多样性与α多样性反应结果一致;丰富度指数与多样性指数、均匀度指数之间存在极显著的相关性,植物多样性与土壤结皮层厚度呈正比,与土壤含水量高低影响不大。[结论]灌木以梭梭—白刺群落为优势群落,草本以雾冰藜—白茎盐生草群落为优势群落,具有物种组成简单,多样性较低的特点,群落在植物生活型上以旱生、超旱生或盐生的小灌木和1年生草本植物占主导地位。  相似文献   

11.
Yields of soybean [Glycine max (L.) Merr.] are affected by the manner in which available resources are partitioned into component plant parts. Little is known about these partitioning processes and much of what has been reported describes indeterminate cultivars or comes from other than field studies. A field investigation was conducted, therefore, on a Goldsboro loamy sand (Aquic Paleudult) to characterize in detail the growth and development of a determinate soybean cultivar ‘Bragg’. Soybean were grown in well watered field plots in four replications from each of which 4 nested samples of 0.3 m2 each were combined at each sampling. Leaf area, dry matter production, internode length, and sample variability were determined nodally at 10‐ to 14‐day intervals from 7 July to 17 October. Plant components at each node were separated into stems, leaf blades, pods, and petioles. Primary and secondary branches were combined in the petiole fraction.

Maximum above ground plant dry weight achieved was 1027 g/m2 and maximum combined nodal dry weight was 92 g/m2 (at node 8), both occurring at the R7 growth stage. Canopy dry weight distribution over time was unique for each plant part. Growth analyses showed that RGR, NAR, LAR, and LWR declined with plant age at a rate that could be described with either linear or exponential models. A maximum CGR of 16.24 g/m2/day occurred at mid‐podfill and declined thereafter due to maturity. Leaf area per node peaked between nodes 7 and 12, decreasing uniformly toward the top of the canopy. Maximum nodal LAI was 0.79 at node 7 on 31 August.

Distribution of dry weight among parts varied with plant age and node position. Maximum dry weights of stems (276 g/m2), petioles (253 g/m2), and leaves (263 g/m2) were found during mid‐podfill. During mid‐August, the dry weights of the stems, petioles, and leaves were similar and approximately 250 g/m2. Stem dry weights had the lowest coefficients of variation of all plant fractions once maximum dry weight was achieved. Internode length varied along the stem with the maximum at node 12. By bloom, expansion of the internodes lower than 12 had ceased; expansion of the eight higher internodes ceased three weeks later. During vegetative growth, the ratio of stem internodal dry weight to internodal length had peak values at the lowest and highest internodes. During reproductive growth, the ratio decreased linearly with internode number. Coefficients of variation (CV) for the combined weight of plant parts, and for stems, petioles, leaves, and pods were relatively constant during the season and were 24.8, 23.4, 38.2, 25.5, and 26.8%, respectively. The CV's for the combined weight of plant parts were somewhat higher at the lowest and uppermost nodes. This variability resulted from the abscission of petioles and leaves in the lower nodes and the initiation of leaves, petioles, and pods in the upper nodes where rapid growth and development was occurring. Time from node initiation to achievement of lowest stable CV was determined for each node and plant part. Plant node position and morphological part with the lowest CV was identified for each sampling date (and growth stage).  相似文献   


12.
Various microorganisms live in association with different parts of plants and can be harmful, neutral, or beneficial to plant health. Some microbial inhabitants of plants can control plant diseases by contesting with, predating on, or antagonizing plant pathogens and by inducing systems for plant defense. A range of methods, including plant growth-promoting microorganisms(PGPMs) as biological control agents(BCAs)(BCA-PGPMs) are used for the biological management and control of plant pathogens. S...  相似文献   

13.
Many new coleus (C. hybridus cv.) cultivars are vegetatively propagated and require different fertilization practices from seed propagated cultivars. Two experiments were conducted to evaluate growth responses of Henna, Indian Summer, Mint Mocha, New Orleans Red, Red Head, and Trusty Rusty to 0, 70, 140, 280 and 420 mg·L?1 nitrogen (N), and Henna, Mint Mocha, Red Head, and Trusty Rusty to 0, 6.2, 12.4, 24.8, or 49.6 mg·L?1 phosphorus (P) to determine optimum constant liquid feed rates to produce marketable size plants from rooted cuttings. Positive growth responses in terms of biomass were found with increasing N rates but not P rates. For medium-sized cultivars such as Henna, Indian Summer, and New Orleans Red, quadratic responses were found in aboveground biomass, and N at 280 mg·L?1 resulted in similar plant size and dry weight as those fertilized at 140 and 420 mg·L?1 N. For large-sized cultivars such as Mint Mocha, Red Head and Trusty Rusty, plant dry weight responded linearly within the N range tested and were greatest at 420 mg·L?1. However, plant visual quality was negatively affected by N rates at 280 and 420 mg·L?1 in that, leaf color became less intense at these high N rates. Plants fertilized at 70 mg·L?1 were smaller than those fertilized at 140 mg·L?1, however, they received similar visual quality ratings because of more intense leaf color. Therefore, N at 70 to 140 mg·L?1 can be used to grow most vegetative coleus for similar marketable quality. Mint Mocha and Henna were the only cultivars responded to P treatments that, 12.4 mg·L?1 P rate resulted in greater biomass than the no-P control. All other cultivars had no response to supplemental P except a linear response in tissue P%. Therefore, supplemental P is not required during the 8 week production period when there is an initial P charge in the substrate. We found that substrate pH decreases with higher P rates, therefore supplemental P fertilizer can be used for adjusting pH. Both N and P rates found optimum in this study are lower than current industry practices (N at 150 to 250 mg·L?1 and P at 24 mg·L?1) and can significantly lower production cost and potential leaching of excessive nutrient into waterway. Nutrient treatments in further study on postharvest performance of vegetative coleus will be selected based on this study.  相似文献   

14.
Abstract

Stem bases from wheat plants in a glasshouse pot experiment conducted under varying nitrogen and two water regimes, were analysed for nitrate (NO3) concentration. The concentration of NO3 at three stages of growth i.e. tillering, jointing and anthesis were related both to rates of applied nitrogen and to shoot dry matter yield at time of sampling. Plotted against rate of increasing nitrogen application, the response curve of NO3 concentration in wheat stem bases was sigmoidal. The level of nitrogen application at which NO3 began to accumulate in the plants was the supply at which plants reached maximum dry matter yield. The concentration of NO3 at which plant yield was 90% of maximum dry matter was taken as the critical level. This concentration was around 1000 ppm NO3‐N at all stages. Compared with plants supplied with unlimited water, plants under moderate water stress accumulated relatively more NO3 but had a similar critical NO3 concentration.

Maximum grain yield was obtained from plants which stayed above the critical level throughout the growing season.  相似文献   

15.
Evaluations of fruit quality and nitrogen, potassium, and calcium concentration of apple (Malus domestica Borkh. cvs. Gala and Golab) grown with five treatments of NO3?:NH4+ ratios were made in pot culture. The concentrations of NO3?:NH4+ ratios were 2.5:0.1, 6:1, 6:0.7, 6:0.5, 6:0.3 meq L?1. Fruit size, percent dry matter, total dissolved solids, total acidity, or juice pH was not affected by increased ammonium in the ratio. Firmness decreased as the proportion of NH4+ increased. Gala and Golab differed in some of these parameters. Concentrations of N and K increased as NH4+ increased, whereas Ca had no trend or decreased. Generally, the treatment of 2.5:0.1 produced fruits with lower N but higher K and Ca concentrations than the other treatments. This research showed that some parameters such as fruit weight, length, and diameter, juice pH, and dry matter were not affected significantly by NH4+ concentration whereas composition was affected.  相似文献   

16.
Lettuce plants (Lactuca sativa L. cv. Grand Rapids) were grown in nutrient solution in controlled environment plant growth chambers to characterize certain qualitative responses to above ambient levels of CO2. Increased plant material produced under high CO2 levels did not differ nutritionally from plants grown under ambient levels. No differences were found in chloroplast pigment content, protein content, or in carbohydrate content on a weight basis. Sequential harvests did reveal, however, that there is a greater accumulation of carbohydrate, under high CO2 conditions, prior to an increased growth rate as the plants reach maturity.  相似文献   

17.
Abstract

A simple and rapid procedure for the determination of nitrate in fresh leaf tissue, suitable for use by relatively untrained operators is presented. The method requires only 4 reagents and can be carried out in less than 20 min from start to finish. A 400 mg sample of fresh leaf tissue is macerated briefly with 5 drops of 10 N sulphuric acid, diluted with 10.0 ml of water and filtered. Nitrate‐N is estimated on an aliquot of the filtered extract by reducing the nitrate to nitrite by shaking with powdered zinc in ammonium hydroxide solution for 3 min. The reduced mixture is allowed to settle (5 min) and an aliquot is withdrawn through a cotton‐wool plug thus removing any particles of the zinc. The filtered aliquot is then reacted with a single colour reagent to yield a pink azo‐dye, the intensity of which is directly proportional to the amount of nitrate.

The method was found to have a coefficient of variation of about 4%. When compared with the phenoldisulphonic acid method for nitrate, on aliquots of the some plant extract, it yielded values which were on average 94.6% of those obtained with the former method. The coefficient of variation between the methods was 7%.  相似文献   

18.
Abstract

A rapid colorimetric method for the determination of boron in soil extracts, plant materials, composts, manures, water and nutrient solution is proposed. The method is rapid, reliable and carried out in aqueous solution. A marked advantage is that boron can be determined in the same soil extract or plant material digest used for determination of other elements.  相似文献   

19.
Current literature review and discussion of the N status of plants as related to their growth and yield and quality of produced product.  相似文献   

20.
植物营养生物学研究方向探讨   总被引：1，自引：1，他引：0  
植物营养生物学是重点研究植物活化、吸收、转运与利用养分的生理、分子及遗传机制的科学。在过去的30年,我国植物营养生物学研究取得了长足的发展,但从国家自然科学基金资助情况分析,与相关学科相比,近10多年来植物营养生物学总体研究力量相对薄弱,缺乏新一代领军人才。一些研究更接近于“纯”植物生物学,与植物营养应用研究出现脱节,对农业绿色发展及化肥产业升级的支撑不够。植物营养生物学研究者应该重视与作物育种、耕作栽培、生态环境、植物保护及化肥产业的合作,跟踪这些领域的研究现状及生产中面临的技术需求,围绕这些领域的技术“瓶颈”开展植物营养基础研究,在提供解决途径的同时创新植物营养生物学机理,从而丰富植物营养学理论。在研究内容上,建议重视控制养分响应度的生理与遗传机制,养分信号与环境信号互作,养分×土壤×管理互作及其对根系生长的影响,养分供应与抗生物胁迫,高产高效的植物营养生理学基础,特种作物的营养机理,化肥产品升级的生物学途径等方向的研究。  相似文献   

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