Contribution of Herbaceous Plants and Their Status and Role in Soil and Water Ecosystem

In this paper,the contemporary understanding process of herbaceous plants and their contributions are elaborated.The systematic idea of"mountain,river,forest,field,lake,and grass are a community of life"has led the grass to enter a new era of development.Broadly speaking,vegetation includes grassland,forest,crop,garden,etc.,while herbaceous vegetation is the most widely distributed on earth.From the macro and micro perspectives of soil and water ecology,this paper discusses the position and role of herbaceous vegetation in the earth's soil and water ecosystem,especially the fundamental position in mountain,river,forest,field,lake,grass and sand.Starting from the concept of soil and water ecology,the integrated protection and systematic management of mountain,river,forest,field,lake,grassland,and sand is proposed.Essentially,it is the protection and management of soil and water ecology,which summarizes various ecological systems on earth.The successful application of herbaceous plants in ecological restoration projects of mine has further enriched and developed the theory of soil and water ecology.

Changes in the root system of the herbaceous peony and soil properties under different years of continuous planting and replanting

The herbaceous peony(Paeonia lactiflora Pall.)has high ornamental value.Replanting problems occur when seedlings are replanted into previous holes.We studied the root system and soil environment of the'Dongjingnvlang'variety under a continuous planting regime of one,four,and seven years,and a replanting regime of one and four years.Under the condition of continuous planting,with the increase of number of years,pH,ammonium nitrogen,and nitrate nitrogen decreased in the rhizosphere and non-rhizosphere soils,whereas organic matter,available phosphorus and potassium,enzyme activities,and the number of bacteria,fungi,and actinomycetes increased.Under the condition of replanting,with the increase of number of years,fungi and actinomycetes in both soils increased,while pH,organic matter,nutrients,enzyme activities,and bacterial number decreased.pH,organic matter,nutrient content,enzyme activity and the number of bacterial were lower in soil replanted for four years,whereas the abundance of fungi and actinomycetes was higher,altering the soil from“bacterial high-fertility”to“fungal low-fertility”with increasing years of replanting.The activity of antioxidant enzymes and MDA content in roots of peony in replanting were higher than those in continuous planting,while the content of osmotic regulatory substances in replanting was lower than that in continuous planting.The results showed that there were no obvious adverse factors in soil during seven years of continuous planting,and herbaceous peony could maintain normal growth and development.However,soils after four years of replanting were not suitable for herbaceous peony growth.Benzoic acid increased with years of replanting,which potentially caused replanting problems.This study provides a theoretical basis for understanding the mechanism of replanting problems in the herbaceous peony.

Niche Characteristics of Herbaceous Plants under Pinus tabuliformis Plantation Forest in Feldspathic Sandstone Area

[Objectives] To explore the niche characteristics of herbaceous plants under Pinus tabuliformis plantation forest in the feldspathic sandstone area,and to provide basic data for maintaining biodiversity and community stability in the local P.tabuliformis plantation forest.[Methods] The types,quantity,average plant height,and coverage of various herbaceous plants were recorded by field survey in a well-growing P.tabulaeformis forest area.Based on the survey data,Shannon and Levins niche breadth index,Levins niche overlap index and ecological response were used to analyze the niche characteristics of herbaceous plants under P.tabulaeformis plantation forest.[Results]( i) There were 35 species of herbaceous plants in the P.tabulaeformis plantation forest in the feldspathic sandstone area.Among them,Stipa bungeiensis had the largest niche breadth indexes with better performance.Because of its strong adaptability,its community was in an obviously advantageous position.( ii) The overall niche width and niche overlap index were generally not high,and understory herb species showed differentiation.( iii) Among the understory herbaceous species,37.15% of the species were developed species,and 62.86% of the species were declining species.Among the 14 dominant species,11 were developmental species.The species with largest the resource occupancy were S.bungeiensis( 0.188 5),Heteropappus altaicus( 0.053 1),and Cleistogenes squarrosa( 0.037 9).[Conclusions] Competition among under herbaceous plants in P.tabulaeformis plantation forest in the feldspathic sandstone area was weak,and the community species had poor utilization of resources and environment.Most of the dominant herbaceous species were in the developing stage,indicating that the P.tabulaeformis plantation community tends to be relatively stable at the current stage.

Impact factors identification of spatial heterogeneity of herbaceous plant diversity on five southern islands of Miaodao Archipelago in North China

Herbaceous plants are widely distributed on islands and where they exhibit spatial heterogeneity.Accurately identifying the impact factors that drive spatial heterogeneity can reveal typical island biodiversity patterns.Five southern islands in the Miaodao Archipelago,North China were studied herein.The spatial distribution of herbaceous plant diversity on these islands was analyzed,and the impact factors and their degree of impact on spatial heterogeneity were identified using CCA ordination and ANOVA.The results reveal 114 herbaceous plant species,belonging to 94 genera from 34 families in the50 plots sampled.The total species numbers on different islands were significantly positively correlated with island area,and the average a diversity was correlated with human activities,while the(3 diversity among islands was more affected by island area than mutual distances.Spatial heterogeneity within islands indicated that the diversities were generally high in areas with higher altitude,slope,total nitrogen,total carbon,and canopy density,and lower moisture content,pH,total phosphorus,total potassium,and aspect.Among the environmental factors,pH,canopy density,total K,total P,moisture content,altitude,and slope had significant gross effects,but only canopy density exhibited a significant net effect.Terrain affected diversity by restricting plantation,plantation in turn influenced soil properties and the two together affected diversity.Therefore,plantation was ultimately the fundamental driving factor for spatial heterogeneity in herbaceous plant diversity on the five islands.

Soil Microbial Community and Enzyme Activity Responses to Herbaceous Plant Expansion in the Changbai Mountains Tundra, China

As one of the most sensitive regions to global climate change, alpine tundra in many places around the world has been undergoing dramatic changes in vegetation communities over the past few decades.Herbaceous plant species in the Changbai Mountains area have significantly expanded into tundra shrub communities over the past 30 yr.Soil microbial communities, enzyme activities, and soil nutrients are intertwined with this expansion process.In order to understand the responses of the soil microbial communities to such an expansion, we analyzed soil microbial community structures and enzyme activities in shrub tundra as well as areas with three different levels of herbaceous plant expansion.Our investigation was based on phospholipid fatty acid(PLFA) analysis and 96-well microtiter plates.The results showed that herbs have expanded greatly in the tundra, and they have become the dominant species in herbaceous plant expansion areas.There were differences for community composition and appearance among the shrub tundra and the mild expansion, moderate expansion, and severe expansion areas.Except for soil organic matter, soil nutrients were increased in herbaceous plant expansion areas, and the total nitrogen(TN), total phosphorus(TP), available nitrogen(AN), and available phosphorus(AP) were greatest in moderate expansion areas(MOE), while soil organic matter levels were highest in the non-expanded areas(CK).The total soil PLFAs in the three levels of herbaceous plant expansion areas were significantly higher than those in the non-expanded areas, and total soil PLFAs were highest in the moderately expanded area and lowest in the severely expanded area(SEE).Bacteria increased significantly more than fungi and actinomycetes with herbaceous plant expansion.Soil hydrolase activities(β-1,4-glucosidase(βG) activity, β-1, 4-N-acetylglucosaminidase(NAG) activity, and acid phosphatase(aP) activity) were highest in MOE and lowest in the CK treatment.Soil oxidase activities(polyphenol oxidase(PPO) activities and peroxidase(PER) activities) were also highest in MOE, but they were lowest in the SEE treatment.The variations in total soil PLFAs with herbaceous plant expansion were mostly correlated with soil organic matter and available phosphorus concentrations, while soil enzyme activities were mostly correlated with the total soil nitrogen concentration.Our results suggest that herbaceous plant expansion increase the total soil PLFAs and soil enzyme activities and improved soil nutrients.However, soil microorganisms, enzyme activity, and nutrients responded differently to levels of herbaceous plant expansion.The soil conditions in mild and moderate expansion areas are more favorable than those in severe expansion areas.

A Whole Plant Herbaceous Angiosperm from the Middle Jurassic of China

In contrast to woody habit with secondary growth, truthful herbaceous habit lacking secondary growth is restricted to angiosperms among seed plants. Although angiosperms might have occurred as early as in the Triassic and herbaceous habit theoretically may have been well adopted by pioneer angiosperms, pre-Cretaceous herbs are missing hitherto, leaving the origin of herbs and evolution of herbaceous angiosperms mysterious. Here we report Juraherba bodae gen. et sp. nov, a whole plant herbaceous angiosperm, from the Middle Jurassic （〉164 Ma） at Daohugou Village, Inner Mongolia, China, a fossil Lagerst^itten that is worldwide famous for various fossil finds. The angiospermous affinity of Juraherba is ensured by its enclosed ovules/seeds. The plant is small but complete, with physically connected hairy root, stem, leaves, and fructifications. The Middle Jurassic age recommends Juraherba as the earliest record of herbaceous seed plants, demanding a refresh look at the evolutionary history of angiosperms.

Different strategies in biomass allocation across elevation in two Gentiana plants on the Yunnan-Guizhou Plateau, China

Patterns of biomass allocation among organs in plants are important because they influence many growth processes.The Yunnan-Guizhou Plateau(YGP)is considered to be one of the most sensitive areas in China to climate changes,but we know little about how current climatic gradients on the plateau influence plant biomass allocation.Gentiana rigescens and G.rhodantha,on the YGP,are important species because they are used in traditional Chinese medicines.We therefore analyzed the biomass allocation patterns of the two species across an elevation gradient(1000–2810 m a.s.l.)on the YGP to understand and predict the impact of climate change on these plant species.We found that the total biomass,reproductive biomass,vegetative biomass,aboveground biomass,and belowground biomass in G.rigescens were all significantly larger than those in G.rhodantha(p<0.05).However,for both species the aboveground biomass was nearly isometrically related to belowground biomass,regardless of elevation,mean annual temperature(MAT)ranging from 8.4℃t to 18.8℃t,and mean annual precipitation(MAP)ranging from 681 to 1327 mm,while the reproductive biomass was allometrically related to vegetative biomass.Intriguingly,there was a significant positive relationship(p<0.05)between the slope of the allometric scaling of reproductive and vegetative biomass and elevation among G.rigescens populations,i.e.plants growing at high elevationsallocate proportionately more biomass to reproduction at larger sizes and less at smaller sizes than plants growing at lower elevations.However,for G.rhodantha the reproductive allocation was negatively correlated with latitude.The results suggested different strategies in reproductive allocation in the two Gentiana plants on the YGP.Further studies are needed to investigate other environmental factors,such as nutrients and light,and genetic factors,in order to understand the trend of reproductive allometry along the environmental gradients.Our study has implications for the management and conservation practices of the two Gentiana species.

Effect of thinning intensity on understory herbaceous diversity and biomass in mixed coniferous and broad-leaved forests of Changbai Mountain

Background:Herbs are an important part of the forest ecosystem,and their diversity and biomass can reflect the restoration of vegetation after forest thinning disturbances.Based on the near-mature secondary coniferous and broad-leaved mixed forest in Jilin Province Forestry Experimental Zone,this study analyzed seasonal changes of species diversity and biomass of the understory herb layer after different intensities of thinning.Results:The results showed that although the composition of herbaceous species and the ranking of importance values were affected by thinning intensity,they were mainly determined by seasonal changes.Across the entire growing season,the species with the highest importance values in thinning treatments included Carex pilosa,Aegopodium alpestre,Meehania urticifolia,and Filipendula palmata,which dominated the herb layer of the coniferous and broad-leaved mixed forest.The number of species,Margalef index,Shannon-Wiener index and Simpson index all had their highest values in May,and gradually decreased with months.Pielou index was roughly inverted“N”throughout the growing season.Thinning did not increase the species diversity.Thinning can promote the total biomass,above-and below-ground biomass.The number of plants per unit area and coverage were related to the total biomass,above-and below-ground biomass.The average height had a significantly positive correlation with herb biomass in May but not in July.However,it exerted a significantly negative correlation with herb biomass in September.The biomass in the same month increased with increasing thinning intensity.Total herb biomass,above-and below-ground biomass showed positive correlations with Shannon-Winner index,Simpson index and Pielou evenness index in May.Conclusions:Thinning mainly changed the light environment in the forest,which would improve the plant diversity and biomass of herb layer in a short time.And different thinning intensity had different effects on the diversity of understory herb layer.The findings provide theoretical basis and reference for reasonable thinning and tending in coniferous and broad-leaved mixed forests.

Herbaceous Cultivation Test of Mulberry in Sichuan Sericultural Area

With Guiteyou 2 as the test mulberry variety, mulberry herbaceous cultivation field was established at the planting densities of 60 000,90 000 and 120 000 plants/hm2, respectively. Hybrid mulberry herbaceous cultivation test was conducted, with Tongxiangqing mulberry field of mid-fist-form at conventional planting density of 4 995 plants/hm2 as the control. The results showed that the leaf yield of herbaceous cultivation mulberry was closely related to the planting density. With the increasing planting density, the leaf yield per plant was decreasing, but the leaf yield per unit area of mulberry field was increasing. The annual leaf yield per unit area in the mulberry field with the average planting density of 120 000 plants/hm2 was 37 560 kg/hm2, 2.14 times of that of the control field. The moisture content of mulberry leaf in herbaceous cultivation field was 4.74% higher than the control; the contents of crude protein, crude fat, crude fiber and crude ash were 1.264%, 0.014%, 0.744% and 0.002%lower than the control, respectively. Comparison of leaf rearing with herbaceous cultivation mulberry and control mulberry showed that there was no significant difference in growth status of silkworm. The cocoon weight, cocoon shell weight, cocoon yield per 10 000 larvae, cocoon filament length and non-broken filament length of Chuanshan × Shushui were 12.81%, 14.29%, 13.85%, 5.95% and 7.68% lower than the control, respectively; but the percentage of common cocoons was 0.16% higher than the control; the cleanness and neatness were 0.2 and 1.25 points higher than the control;the filament size was 0.196 dtex lower than the control. The cocoon weight, cocoon shell weight, cocoon yield per 10 000 larvae, cocoon filament length and non-broken filament length of Jingsong × Haoyue were 11.06%, 10.20%, 11.53%, 9.46% and 9.03% lower than the control, respectively;but the percentage of common cocoons was 1.77% higher than the control; the cleanness and neatness were 0.12 and 2.50 points higher the control;and the filament size was 0.196 dtex lower than the control.

新农科背景下草类植物育种学课程教学改革与探索

草类植物育种学是草业科学专业的核心课程,该课程的专业知识储备和实践试验能力提升在培养适应新农科建设需要的高素质草业科学专业人才方面具有重要意义。然而,对标新农科建设要求,该课程在实际教学中存在教学内容陈旧、教学方法单一和实践教学不足等问题,这种知识体系和教学模式难以满足现代种业发展对高水平育种人才的需求。教学团队通过构建网络教学平台,加强教材编写,引入最新研究进展和技术,以及引进育种专业软件DeltaGen和国际智力等手段,对教学内容、教学方法和课程考核方法进行了改革。经过课程改革,学生对草类植物育种的学习兴趣得以激发,实践和创新能力得到增强,教学质量得到提升。

新农科背景下草类植物栽培学课程思政教学改革探索

立德树人是高校教育的根本任务,课程思政是重要举措。新时代新农科建设下,草类植物栽培学课程思政围绕教学团队、理论教学、实验教学、实践教学、教育手段、教学方法和考核评价等方面进行改革探索,挖掘其思政元素以构建完整的课程思政知识体系,强化专业理论与思政知识融合,发挥二者同向同行的协同效应,为其他专业课程思政提供一定的参考价值。

中国河湖岸带草本植物氮磷化学计量学及内稳性特征

河湖岸带是拦截净化氮磷等陆源污染物进入河湖水体的最后屏障,河湖岸带草本植物的稳定性影响着其对污染物的拦截净化能力,研究河湖岸带草本植物生态化学计量学及内稳性,可为河湖岸带草本植物群落恢复和构建提供基础数据。通过对中国河湖岸带草本植物地上部氮(N)、磷(P)含量及土壤或沉积物、水体进行数据收集,分析了植物氮磷化学计量学和内稳性特征及其与环境因子的关系。结果表明:青藏高原湖区草本植物具有较高的N含量(湿生植物:20.51 g·kg^(-1),水生植物:29.81 g·kg^(-1))和较低的P含量(湿生植物:1.39 g·kg^(-1),水生植物:0.99 g·kg^(-1)),N:P>14,表现为P限制,而其他湖区草本植物具有较高的P含量(2.73 g·kg^(-1)),N:P<14,表现为N限制。各湖区植物N、P含量及其比值在空间上具有一定差异,青藏高原湖区水生植物N含量最高,东北平原与山地湖区最低(P<0.05);东北平原与山地湖区湿生和水生植物P含量最高(P<0.05);青藏高原湖区湿生和水生植物N:P最高,东北平原与山地湖区最低(P<0.05)。植物N、P含量及N:P受环境中P含量影响最大,其次是环境中N:P和N含量。内稳性模型表明河湖岸带草本植物属于稳态型,其中湿生植物内稳性指数HN、HP及HN:P大于水生植物,表明水生植物受环境胁迫时响应较大,水生和湿生植物对环境中N、P含量变化响应的差异表明水生和湿生植物对环境中N、P不同的保守利用策略。

准噶尔无叶豆对邻近草本植物群落多样性的影响及其与土壤因子的关系

为明确荒漠豆科植物对邻近草本植物群落物种多样性的影响及其与土壤因子的关系,以古尔班通古特沙漠优势豆科植物准噶尔无叶豆(Eremosparton songoricum)及其邻近草本植物群落为研究对象,采用野外调查法分析群落及物种多样性特征,综合对比准噶尔无叶豆与草本植物共存群落(LH)和仅草本植物群落(NH)的6种多样性指数,进一步运用冗余分析(RDA)探讨物种多样性与土壤因子之间的关系。结果表明:1)在NH群落中,共有植物8科11属11种,其中菊科植物种类最多;在LH群落中,共有植物4科6属6种,其中藜科植物种类最多。2)NH群落多样性指数H、D、R显著高于LH群落,优势度指数C则表现出相反的特征(P<0.05),说明NH群落物种丰富度相对较高,但物种分布优势性较差,LH群落中物种优势度较为突出。3)在垂直方向上,不同群落土壤有机碳(SOC)、有机质(SOM)、全氮(TN)随着土层深度的增加而逐渐减小,具有明显的“表聚性”特征;在相同土层中,LH群落显著高于NH群落(P<0.05)。4)冗余分析显示,对NH群落和LH群落物种多样性变化有显著性影响的主要土壤因子分别为土壤硝态氮(NO3--N)和全磷(TP)。综上所述,准噶尔无叶豆对邻近草本植物群落的物种多样性及环境因子具有一定的影响,存在准噶尔无叶豆的群落中草本植物物种丰富度低,但群落土壤结构较好,肥力更佳,具有群落优势性。

祁连山东部森林林分结构和环境因素对草本物种多样性的影响

林下草本物种多样性在维持西北干旱与半干旱地区的生态系统服务功能方面起着重要作用,探究其相关影响因素,可为祁连山东部地区的人工生态公益林的可持续经营提供理论基础。选取位于祁连山东部地区的针叶纯林、阔叶纯林、针叶混交林、针阔混交林(人工林)为研究对象,在相关性分析的基础上构建草本物种多样性的多因素参数预测模型和结构方程非参效应模型,探究多重因素(林分空间结构、林分非空间结构、环境因子)间的关系以及对林下草本物种多样性的影响程度。结果表明:(1)针阔混交林中林下草本的科、属、种数量最多。(2)平均胸径、平均树高、角尺度、混交度、大小比、坡度与草本物种多样性呈显著性相关(P<0.05)。(3)平均胸径是影响林下草本Simpson多样性指数的关键因子;坡度是影响林下草本Shannon-Wiener多样性指数的关键因子;角尺度、混交度是影响Pielou均匀性指数的关键因子;平均胸径、平均树高是影响物种丰富度的关键因子。(4)结构方程非参效应模型显示林分结构是影响草本物种多样性的关键因子(P<0.001),环境因子是影响草本物种多样性的重要因子(P<0.05)。因此,在后续森林植被恢复措施中,应当着重考虑林分的空间结构,形成随机分布的异龄复层混交林,以增加光合利用效率并遵循生态位互补理论,从而提高草本多样性。

基于无人机遥感的多特征组矿区草本植物地上生物量反演

植被地上生物量可作为评价矿山生态修复地生态功能的重要指标,为实现对修复地地上植被生物量快速、准确的预测,以安徽省铜陵市铜官山矿区草本植物地上生物量为研究对象,将无人机高分辨率多光谱影像作为数据源,提取了单波段光谱反射率、植被指数两种光谱特征以及各波段纹理特征变量,并利用高精度DEM(digital elevation model)生成地形特征,再先后使用灰色关联法和熵权法对光谱特征和纹理特征分别进行筛选,进而将筛选出的特征变量和地形特征变量分为光谱特征组和多特征组。采用反向传播神经网络(back propagation neural network,BPNN)、卷积神经网络(convolutional neural network,CNN)以及Elman神经网络3种机器学习算法分别构建基于光谱特征组和多特征组的生物量预测模型,比选精度较高的矿区草本植物地上生物量反演模型。结果表明,在光谱特征基础上引入纹理特征和地形特征后3种反演模型精度都有相应程度提高,其中,基于多特征组构建的BPNN模型表现出最优性能,其决定系数(R2)为0.841,均方根误差为11.813 g·m-2,并同时对3种模型进行交叉验证,进一步证明了基于多特征组的BPNN模型更加稳定,反演精度最优。然后,采用最优反演模型对研究区域内植被生物量进行分级评估,结果显示区内生物量集中于20~40 g·m-2,研究区域内植被生物量整体偏低。研究结果可为矿区草本植物生物量反演研究提供理论支持。

兰州市3所高校自生草本植物多样性调查与分析

自生植物是建设低成本、低维护、可持续发展的节约型景观不可缺少的植物材料。为了解兰州市高校自生草本植物资源现状,使其更好地在园林中应用,采用网格布样法于2023年4~10月对甘肃农业大学、兰州大学、兰州理工大学(老校区)校园自生草本植物进行逐月调研。将其所处生境划分为4类,共计样点146个,样方438个,运用Shannon-Wiener指数、Ducan检验等计算方法对物种组成和多样性特征进行分析。结果表明,3所高校共调研到自生草本植物32科87属103种,乡土植物61种,占59.22%;外来入侵植物21种,占20.39%。生活型以多年生草本为主,共63种,一二年生草本40种。物种频度排名前3的为蒲公英Taraxacum mongolicum(67.63%)、早开堇菜Viola prionantha(55.76%)、白三叶Trifolium repens(48.32%),在所有样地中数量较多,有一定生长优势。优势科为菊科Compositae和禾本科Poaceae,为34属44种,菊科植物占比最高;其中蒲公英在林荫、草地、道路3种样地中重要值均位于前5,在甘肃农业大学林荫样地中排第1,重要值为42.21。从空间格局看,林荫和草地生境物种较多,分别为59种和47种,其Shannon-Wiener指数依次为林荫>草地>道路>水边;Shannon-Wiener指数随月份呈先升后降再升趋势,在6月、10月最高,均值分别为6.41和6.17,各生境样地多样性处于较高水平,为与气候、人为干扰、管理水平有关。校园自生草本植物具有良好的生态适应性和植物景观效果,科学利用和规划可形成富有特色和生态意义的园林植物景观。

草本植物对硫酸盐渍土强度影响的试验研究

为探究草本植物生长对硫酸盐渍土的强度影响,分析其生物量与盐渍土强度相关关系;选取常见的高羊茅、黑麦草、早熟禾做为试验用草,定期测定草本植物的不同部分生物量和根土复合体的抗剪强度。其中高羊茅、黑麦草的生物量增量高于早熟禾,三种根土复合体的强度均大于素土强度,其粘聚力也明显提高。但内摩擦角变化并不显著,与素土相比仅有小幅度提高。草本植物的生长可在一定程度上提高硫酸盐渍土的土体强度,高羊茅、黑麦草对盐渍土的固土效果优于早熟禾,早熟禾不适宜在盐渍土上种植。

城市生态公益林再野化的草本植物及其生境热点快速监测识别技术

受乔木遮挡影响,难以采用遥感技术监测城市生态公益林内现状草本植被,而人工监测费时费力。为攻关此难题,以生境热点监测识别为突破口,开发一种适用于中观尺度城市生态公益林的快速监测识别技术体系,通过分析高分辨率的遥感影像,快速识别原生草本植物多样性较高的空间范围,对此类空间开展重点法抽样,经对上海市金山区农林水乡生态公益林实地验证,该方法效果较好,具体表现为:单独使用一种抽样法时,重点法的探测效率更高,草本原生种探测效率约为79%,优于系统法+路径法组合使用(72%);两种方法组合使用时,重点法能够将物种探测效率提高16%~24%,其中系统法+重点法的草本原生种探测效率约为88%,路径法+重点法的草本原生种探测效率约为96%。研究结果说明生境热点内的草本原生种数量较多,生境热点识别技术有效;明确生境热点的空间范围,能够提高生物多样性监测效率、降低监测人力和时间成本,为生态修复工程规划、设计、施工和评估提供重要的空间信息;同时,利用人工智能技术开展公众参与监测研究,降低了监测成本,能够保障监测识别的准确性和可持续性。因此,该技术能够为城市生态公益林再野化提供有力的技术支持,具有广阔的应用前景。

干旱及复水对荒漠绿洲过渡带一年生草本植物生长及生理特性的影响

一年生草本植物种群组成荒漠与绿洲生态系统的恒有性植物层片,在防风固沙和保护绿洲生态系统稳定方面具有重要的作用。本研究选取河西走廊荒漠绿洲过渡带人工林下典型5种一年生草本植物虎尾草、狗尾草、白茎盐生草、沙米和雾冰藜为研究对象,采用盆栽试验模拟干旱胁迫及复水,测定5种植物幼苗根系和叶片的生长(株高、根体积、根系平均直径、根系总表面积、根系总长和根系干重)与生理指标(根系活力、光合色素、丙二醛、渗透调节物质和抗氧化酶活性)的变化特征和规律,分析其对干旱环境的适应能力。研究结果表明,轻度干旱胁迫(土壤水分相对于CK减少2%)对5种一年生草本植物生长影响较小,甚至有一定的促进作用;中度(土壤水分相对于CK减少4%)和重度(土壤水分相对于CK减少6%)干旱胁迫下植物生长受到明显抑制。随着干旱胁迫程度的加剧,5种植物根系和叶片的丙二醛、过氧化物酶活性和渗透调节物质含量呈上升趋势;而根系活力呈下降趋势。禾本科一年生草本植物虎尾草和狗尾草根系酶活性(超氧化物歧化酶)随干旱胁迫程度的加剧呈持续增加的趋势;藜科一年生草本植物沙米和雾冰藜随干旱胁迫程度的加剧表现出先增加后下降的趋势。复水处理后,5种植物的生长和生理均得到不同程度的补偿,且根系的恢复能力高于叶片,浅根系植物的恢复能力优于深根系的。5种一年生草本植物的抗旱性具有显著差异,依次为狗尾草>白茎盐生草>雾冰藜>虎尾草>沙米。

大气氮沉降对云南亚热带森林地表草本层植物生长的影响

[目的]研究不同浓度大气氮沉降条件下云南亚热带常绿阔叶林生态系统地表草本层植被的生长情况,探讨大气氮沉降对森林生态系统植被组成和结构功能的影响。[方法]以云南亚热带常绿阔叶林生态系统为研究对象,设置0、1、5、10、15和30 g/(m^(2)·a)共6个施氮梯度,采用每30 d 1次林冠下人工喷施的方式对野外样地连续进行2年施氮处理,观察2年后试验样地内地表草本层植被的多样性、丰富度、株高和生物量等生长特征。[结果]随着施氮浓度的增大,植物丰富度、株高和生物量也逐渐增大,在年均30 g/(m^(2)·a)浓度梯度样地中,上述各项数据均达到最大值;而植物多样性则在5 g/(m^(2)·a)浓度梯度样地中达到最大值,为(13±3)种/m^(2)。植物地上部生物量占其总生物量比重较大,为(0.69±0.06)~(0.77±0.09),且呈随着施氮浓度的增大而逐渐降低趋势;植物地下部生物量占其总生物量比重相对较小,为(0.23±0.03)~(0.32±0.04),且呈随着施氮浓度增大而逐渐增加的趋势。[结论]证明了大量大气氮沉降对森林生态系统植物物种多样性的消极影响,明确了不同浓度大气氮沉降对地表草本层植物地上部和地下部之间生物量分配规律的影响,为受大气氮沉降干扰严重的森林生态系统的科学管理及合理开发利用提供理论依据和实际参考。