植被与侵蚀控制:坡面生态工程基本原理探索

在与近地面大气和与表层至浅层土壤的相互作用中,植被表现出相应的水文－机械效应,形成一定的抗蚀护坡工程性状,坡面生态工程把这些植被性状和土壤结合起来,用于斜坡的保护工程,在过去几十年中,随着对植被－土壤相互作用及其侵蚀控制意义认识的深化,使坡面生态工程应用得到迅速发展,成为生态环境建设和工程坡面保护的重要手段,这个生态学途径的一个重要内容是“土壤－植被系统”的概念,以及由此推导出的系统生物学和工程学     

黄土丘陵区坡面植被盖度及其配置格局的水蚀效应模拟

黄土高原因土壤侵蚀严重被视为生态脆弱地带,探讨植被盖度及其所处坡位对土壤侵蚀的响应,对坡面侵蚀产沙的预测和调控具有重要意义。基于WEPP模型情景模拟,分析了分布广泛、耐旱性强的长芒草和典型恢复灌木植被柠条在不同雨强(0.5、1.0、1.5 mm/min)、不同植被盖度(20%、40%、60%、80%)和不同坡位(坡上、坡中、坡下)条件下的土壤侵蚀变化情况,运用双因素方差分析和相关贡献指数阐明坡面侵蚀产沙特征对坡位和植被盖度交互作用的响应,并提出植被配置的优化模式。结果表明:(1)提高植被有效覆盖度是减小土壤侵蚀的重要举措,且当植被分布在下坡位时坡面土壤侵蚀最少;(2)植被盖度可以有效减少产沙量。小雨强时,柠条和长芒草随盖度增加对泥沙的拦截率分别从38%增加到90%,64%增加到96%;中、大雨强时,植被盖度小于20%或者大于80%时,长芒草坡面产沙量大于柠条坡面。盖度为40%—60%时,长芒草坡面产沙量小于柠条坡面;(3)双因素方差分析表明:坡位和植被盖度对坡面侵蚀产沙量有极显著的影响(P0.001);当植被是长芒草时,坡位和植被盖度交互作用对坡面侵蚀产沙有显著影响(P0.01),植被是柠条时,坡位和植被盖度交互作用对坡面侵蚀产沙作用不显著;(4)通过模拟柠条和长芒草不同配置情景得出:长芒草分布在坡面下部产沙量较小,且当柠条和长芒草配比为1∶2时产沙量最小。     

典型黑土区坡面上方汇流和土壤管道崩塌对坡面水蚀的影响

分析坡面上方汇流和土壤管道崩塌对黑土坡面水蚀过程的影响,可为黑土侵蚀退化防治提供重要科学依据。本研究基于坡面汇流模拟试验,设计3个上方汇流强度和3种近地表土壤水文条件(无土壤管道、有土壤管道无管道流、有土壤管道流),研究坡面上方汇流和土壤管道崩塌对黑土坡面水蚀过程的影响,量化土壤管道侵蚀对黑土坡面侵蚀的贡献。结果表明：1)坡面侵蚀量随上方汇流强度的增加而增加,当上方汇流强度从30 L·min^-1增加到40和50 L·min^-1时,坡面侵蚀量分别增加100.0%～111.5%和214.8%～289.2%。2)土壤管道发生和管道流形成加剧了坡面水蚀过程,30、40和50 L·min^-1上方汇流强度下有土壤管道无管道流和有土壤管道流处理的坡面侵蚀量分别是无土壤管道处理的1.4～1.6倍和1.7～2.1倍。此外,3种上方汇流强度下有土壤管道无管道流和有土壤管道流处理的土壤管道侵蚀对坡面土壤侵蚀的贡献分别为26.7%～37.6%和40.5%～51.9%。3)土壤管道崩塌加剧了细沟侵蚀过程,30、40和50 L·min^-1...     

沈阳市东陵区丘陵坡地坡面太阳直射光的分布及其分析

沈阳市东陵区丘陵坡地坡面太阳直射光的分布及其分析郭林海（中国科学院沈阳应用生态研究所,１１００１５）ＤｉｓｔｒｉｂｕｔｉｏｎｏｆＤｉｒｅｃｔＳｏｌａｒＲａｄｉａｔｉｏｎｏｎＨｉｌｌｙＳｌｏｐｅｓｏｆＤｏｎｇｌｉｎｇＤｉｓｔｒｉｃｔｏｆＳｈｅｎｙａｎｇＭｕｎｉｃｉｐａｌｉｔｙａｎｄＩｔｓＡｎａｌｙｓｉｓ￥ＧｕｏＬｉｎｈａｉ（ＩｎｓｔｉｔｕｔｅｏｆＡｐｐｌｉｅｄＥｃｏｌｏｇｙ,ＡｃａｄｅｍｉａＳｉｎｉｃａ,Ｓｈｅｎｙａｎｇ１１００１５）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（１）：５９－６１．Ｂａｓｅｄｏｎｔｈｅｌａｔｅｓｔ１：５００００ｔｏｐｏｇｒａｐｈｉｃｍａｐ,ｔｈｅ１：１０００００ｓｌｏｐｅｇｒａｄａｔｉｏｎｍａｐｉｓｄｒａｗｎｏｕｔａｎｄａｒｅａｃａｌｃｕｌａｔｉｏｎｉｓｍａｄｅ．Ｔｈｅｄｉｒｅｃｔｓｏｌａｒｒａｄｉａｔｉｏｎｉｎｔｙｐｉｃａｌｓｉｔｅｓｏｆｔｈｅｄｉｓｔｒｉｃｔｉｓｍｅａｓｕｒｅｄａｎｄｃａｌｃｕｌａｔｅｄ,ａｎｄｔｈｅｖａｒｉａｔｉｏｎｃｕｒｖｅｓｏｆａｎｎｕａｌｆｌｕｘｏｆｄｉｒｅｃｔｓｏｌａｒｒａｄｉａｔｉｏｎｏｎｖａｒｉｏｕｓｓｌｏｐｅｄｉｒｅｃｔｉ     

黄土丘陵沟壑区撂荒坡面种子雨特征

在纸坊沟流域3个撂荒阳坡各设置30个种子雨收集器,于2010年10月—2013年4月收集种子,2011和2012年8月进行植被调查,研究黄土丘陵沟壑区撂荒植被恢复过程中种子雨动态特征及其与地上植被的关系.结果表明:撂荒坡面种子雨来自于17个科的37个物种,主要有达乌里胡枝子、草木樨状黄耆、狗尾草、糙隐子草、长芒草、白羊草、猪毛蒿、铁杆蒿和阿尔泰狗哇花,占种子雨总量的95.8%;种子雨中仅有3个外来物种,与地上植被物种组成的相似性系数为0.77;2011年5月—2012年4月和2012年5月—2013年4月种子雨的平均密度分别为3737和6449粒·m-2,存在显著的"大小年"现象;收集期间不同位置收集器收集的物种数为7~15个,种子雨密度为3853~37923粒·m-2.研究区种子扩散受到限制,种子雨密度与其他草地相比处于中等水平,种子雨的时空分布受降雨和微地形等因素的影响存在明显的异质性.     

六盘山叠叠沟小流域典型坡面土壤水分的植被承载力

确定土壤水分的植被承载力是我国北方半干旱地区合理调控土壤水分和植被生长关系、科学恢复林草植被的核心问题。我国北方半干旱地区的土壤水分主要来自大气降水, 作为土壤水分限制型生态系统的坡面植被, 植物种类和植被密度等结构特征与降水量紧密相关。根据六盘山石质山区的特点, 基于水量平衡原理, 建立了阴坡华北落叶松(Larix principis-rupprechti)和阳坡草地的土壤水分植被承载力数学模型, 即由4~10月的生长季降雨量(P)计算得到可承载的叶面积指数(Leaf area index, LAI)公式: LAI_tree= exp((0.773 1×P-186.12)/146.46)和LAI_grass= exp((0.511 2×P-345.93)/227.89), 并提出了考虑坡面水分再分配影响的不同坡位的土壤水分植被承载力计算方法。阴坡华北落叶松的植被承载力(用LAI表示)从坡顶的1.45升高到坡中的4.83, 然后稳定在3.0~3.3。对于阳坡草地, 土壤水分可承载的LAI从坡顶的0.37上升到坡中的0.46, 然后在0.41~0.47之间变动, LAI的计算值与实测值较为接近, 计算结果比较合理。     

论乌兰敖都地区沙丘坡面直射光的分布

乌兰敖都位于内蒙古自治区东部的科尔沁沙地中部,是西辽河中上游流域干旱地带的中心。境内分布着石质残丘和起伏的风积沙丘而呈现坨甸相间的景观,石质残丘、流动沙丘和固定沙丘占有很大比例,流动沙丘和固定沙丘(包括半固定沙丘在内)占总面积30%左右。由于地形起伏不平,下垫面性质的不同引起小气候、土壤和植被的显著差异。在本地区的半干旱气候条件下,光是决定生态系统生产力的主要因素之一,也是植物生长的唯一能源。本文根据1983—1984年实际观测资料,着重讨论乌兰敖都地区沙丘不同坡面对直射光到达量的影响,为沙地的综合利用和改造提供科学依据。一、计算方法沙丘不同坡面上直射光到达量,是指在单位时间内投射到单位坡面积上的直射光通量,     

运用案例教学模式进行“生态工程的基本原理”的教学

以"生态工程的基本原理"这个核心知识为联结点,采用案例教学模式,师生同建具有自我生长活力的知识网络系统,以此为基础借助一定的情境,促进学习的迁移、知识的理解和问题的解决;并通过教学反思,形成"实践理论"。     

吕梁关帝山不同植被坡面土壤优先流特征及其影响因素

土壤优先流对坡面产流和流域水循环具有重要影响,研究坡面优先流的特征及其影响因素对理解坡面优先流的产生机理有重要意义.本研究以关帝山针阔混交林、针叶林和灌丛3种植被为对象,采用野外亮蓝示踪实验和室内图像解析技术,揭示不同植被类型、不同坡位点处土壤优先流在垂直和水平方向的空间异质性,并分析土壤理化性质对其影响.结果 表明:...     

半干旱黄土区坡面尺度柠条生长状况及影响要素分析

以半干旱黄土丘陵区典型小流域坡面大规模人工种植柠条林为例,基于坡面不同部位柠条生长状况和生境条件调查,定量分析了地形变化、土壤水分及灌木密度对柠条生长的直接、间接影响及其贡献率。结果表明:(1)东坡大株柠条生长明显好于南坡,下坡位柠条生长状况略好于中上坡位,其他各坡位之间柠条生长状况差异较小;(2)大株柠条生长与浅层土壤水分有正相关关系,而与灌木密度和深层土壤水分则呈负相关关系;大株柠条灌木高度、灌木纵截面积和冠幅体积对浅层土壤水分的响应敏感,冠幅长度对坡向和坡位的响应较为敏感,冠幅宽度对灌木密度的响应较为敏感;(3)地形和土壤水分变化解释了59.9%的大株柠条生长变异,其中坡向、坡位和浅层土壤水分是影响大株柠条生长的主导环境因子,它们分别解释了21.1%、16.0%和13.1%的柠条生长变化。研究认为半干旱黄土区人工植被恢复既要重视空间布局,也要在后期实施必要的管理措施以维持人工林地的稳定性。     

城郊型生态农业系统能量流动数量特征动态变化的研究

以云南小甸头村作为城郊型生态农业系统的典型研究对象,分析其种植业和养殖业的结构、能量输入、输出及利用率６年的动态变化．结果表明：①系统结构从传统的种粮型转变为猪、鸡与粮、菜商品经济型;②种植业、养殖业和系统的经济收入逐年增加;③种植业光能利用率逐年增加,能量产投比在１９８７～１９９０年增加,１９９０年以后下降;④养殖业饲料转化率和能量转化率均为降低的趋势;⑤系统能量利用效率在生态农业建设初期增加,以后降低．在此基础上,提出了种植业和养殖业的调控对策为种植业应稳定粮食作物播种面积,控制人工辅助能输入;养殖业应增强饲料自给力,完善养殖技术,增加效益     

典型农业生态工程运行机制分析—以山东省西单村为例

通过对典型农业生态工程结构的研究,分析了生态农业系统的运行机制,结果表明,结构多样性与主导性关系的协调问题,是目前制约农业生态系统良性循环的根本问题,山东省西单村农业生态系统之所以以前期能够保持持续稳定发展,后期出现减缓趋势,主要原因也是由于其系统的结构多样性比较高,结构多样性指数最高达0．6556,结构链内部各组分之间的协调性超过90％,而系统实际主导性则较低,结构主导性指数最高为0．2574,系统的最高协调性指数只有0．1327,因此,要保证系统的可持续发展,必须保证系统结构的协调性。     

植物基因工程中化学诱导表达系统研究近况

利用可诱导表达系统可使目的基因在特定的时间内表达 ,从而有利于我们研究其基因产物的作用。本文着重介绍了几种利用植物远缘物种的调控元件构建而成的化学诱导系统 ,及它们在植物基因工程中的应用。     

ATP-Activated Nonselective Cation Current in NG108-15 Cells

Abstract: ATP (1 mM) induced a biphasic increase in intracellular Ca²⁺ concentration ([Ca²⁺]_i), i.e., an initial transient increase decayed to a level of sustained increase, in NG108-15 cells. The transient increase was inhibited by a phospholipase C inhibitor, 1-[6-[[17β-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U73122), whereas the sustained increase was abolished by removal of external Ca²⁺. We examined the mechanism of the ATP-elicited sustained [Ca²⁺]_i increase using the fura-2 fluorescent method and the whole-cell patch clamp technique. ATP (1 mM) induced a membrane current with the reversal potential of 12.5 ± 0.8 mV (n = 10) in Tyrode external solution. The EC₅₀ of ATP was ～0.75 mM. The permeability ratio of various cations carrying this current was Na⁺ (defined as 1) > Li⁺ (0.92 ± 0.01; n = 5) > K⁺ (0.89 ± 0.03; n = 6) > Rb⁺ (0.55 ± 0.02; n = 6) > Cs⁺ (0.51 ± 0.01; n = 5) > Ca²⁺ (0.22 ± 0.03; n = 3) > N-methyl-d -glucamine (0.13 ± 0.01; n = 5), suggesting that ATP activated a nonselective cation current. The ATP-induced current was larger at lower concentrations of external Mg²⁺. ATP analogues that induced the current were 2-methylthio-ATP (2MeSATP), benzoylbenzoic-ATP, adenosine 5′-thiotriphosphate (ATPγS), and adenosine 5′-O-(2-thiodiphosphate), but not adenosine, ADP, α,β-methylene-ATP (AMPCPP), β,γ-methylene-ATP (AMPPCP), or UTP. Concomitant with the current data, 2MeSATP and ATPγS, but not AMPCPP or AMPPCP, increased the sustained [Ca²⁺]_i increase. We conclude that ATP activates a class of Ca²⁺-permeable nonselective cation channels via the P_2z receptor in NG108-15 cells.     

Genetic engineering of parthenocarpic fruit development in tomato

Parthenocarpy was engineered in two genotypes of Lycopersicon esculentum Mill. by using the DefH9-iaaM chimeric gene. The parthenocarpic trait consists of fruit set and growth in the absence of fertilization. Seedless parthenocarpic fruits were obtained from emasculated flowers, and fruits with seeds from pollinated flowers. All parthenocarpic tomato plants analysed expressed the DefH9-iaaM gene during flower development. The fruit set percentage of emasculated transgenic flowers was similar to that of control plants. In 7 out of 8 independent transgenic plants, the fresh weight of fruits derived from pollinated or emasculated flowers did not significantly differ from that of fruits obtained by pollination of the control plants. The pH of the parthenocarpic fruit was generally unaffected and the soluble solid concentration was either unchanged or increased. Thus, the DefH9-iaaM gene is a genetic tool that might be used to improve tomato productivity.     

14-3-3蛋白对植物发育的调控作用

14-3-3蛋白是高度保守并在真核生物中普遍存在的一类调节蛋白。不同的14-3-3蛋白同工型具有不同的细胞特异性, 并通过识别特异的磷酸化序列与靶蛋白相互作用, 被称为蛋白质与蛋白质相互作用的桥梁蛋白。在植物生长发育过程中, 14-3-3蛋白通过与其它蛋白的相互作用参与多种植物激素信号转导、各种代谢调控、物质运输和光信号应答等调控过程。该文主要对近年来有关14-3-3蛋白在植物生长发育中的调控作用, 特别是14-3-3蛋白参与调控植物激素信号转导等方面的研究进展进行综述。     

Developmental regulation of 14-3-3 ϵ isoform in rat heart

Human heart cDNA sequencing yielded a cDNA clone that is similar in DNA and amino acid sequences to that of mouse 14-3-3 ϵ isoform. The 6xHis-tagged H1433ϵ recombinant protein was expressed in Escherichia coli and its size was approximately 30 kDa. From Northern blot results with human multiple tissues, human skeletal muscle was found to have the highest level of h1433ϵ mRNA expression, whereas Northern blots of human cancer cell lines detected the highest mRNA level of h1433ϵ in colorectal adenocarcinoma SW480. The protein expression level of h1433ϵ and Raf-1 is found to be regulated coordinately during rat heart development, and their protein expression was highest from 14.5 to 16.5 days postcoitum. J. Cell. Biochem. 68:195–199, 1998. © 1998 Wiley-Liss, Inc.     

农业非点源污染研究现状与发展趋势

水危机已成为世界上最引人关注的问题之一。无论是发达国家,还是发展中国家,都已经或即将面临着这一危机。而在干旱与半干旱地区尤为紧迫。引起水危机的主要原因有二：一是从长远来讲,水资源是有限的,而目前由于世界人口持续增加引起对水资源需求的膨胀使得这一危机加...     

Developing manufactured soils from industrial by‐products for use as growth substrates in mine reclamation

Suitable soils for reclamation can be acquired through excavation and translocation of local soils, increasing the industrial footprint on previously undisturbed lands and causing negative environmental impacts. Manufactured soils (Technosols) could be a viable soil source when the availability of suitable natural soils is limited. The purpose of this study was to manufacture a Technosol from an admixture of woody residuals, primary paper sludge, and two subtypes of nonacid generating crushed mine rock, to function as a growth substrate for revegetation of mined land. Technosols manufactured with 0, 25, 50, and 75% organic materials (v/v) were assessed in a 10‐week growth study using annual ryegrass biomass production and allocation as a performance indicator. Technosols containing no organic materials had significantly lower plant nutrient concentrations than Technosols containing an organic constituent and, after 5 weeks of growth, ryegrass grown on nonorganic Technosols had greater root:shoot ratios than ryegrass grown on organic Technosols. Organics increase the water holding capacity and nutrient concentrations of Technosols and should be included in manufacturing Technosols for revegetation. Technosols manufactured with primary paper sludge produced lower shoot biomass than Technosols manufactured with woody residuals, which could be in part due to the higher pH of the paper sludge. Technosols can be manufactured for revegetation purposes and individual components should be assessed before and after mixing. Further development of Technosols should include field testing and amendment or fertilizer use to improve soil nutrient content.     

Combining metabolic engineering and biocompatible chemistry for high-yield production of homo-diacetyl and homo-(S,S)-2,3-butanediol

Biocompatible chemistry is gaining increasing attention because of its potential within biotechnology for expanding the repertoire of biological transformations carried out by enzymes. Here we demonstrate how biocompatible chemistry can be used for synthesizing valuable compounds as well as for linking metabolic pathways to achieve redox balance and rescued growth. By comprehensive rerouting of metabolism, activation of respiration, and finally metal ion catalysis, we successfully managed to convert the homolactic bacterium Lactococcus lactis into a homo-diacetyl producer with high titer (95 mM or 8.2 g/L) and high yield (87% of the theoretical maximum). Subsequently, the pathway was extended to (S,S)-2,3-butanediol (S-BDO) through efficiently linking two metabolic pathways via chemical catalysis. This resulted in efficient homo-S-BDO production with a titer of 74 mM (6.7 g/L) S-BDO and a yield of 82%. The diacetyl and S-BDO production rates and yields obtained are the highest ever reported, demonstrating the promising combination of metabolic engineering and biocompatible chemistry as well as the great potential of L. lactis as a new production platform.