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1.
为了探讨珍稀树种对短期氮素添加的响应,该文研究了氮素添加(0、0.1、0.2、0.4和0.6g·kg~(-1)土)对观光木、棱角山矾和半枫荷幼苗生长和生物量分配的影响。结果表明:3个树种幼苗对外源氮素添加的反应不同,施氮显著促进观光木幼苗株高、基径、冠幅以及全株生物量和各部分生物量的增加,中低氮促进半枫荷幼苗的生长,但高氮抑制其生长;少量施氮对棱角山矾幼苗的形态和生物量参数没有产生显著影响,中量施氮抑制其生长。氮素营养的改变显著影响3种植物幼苗的生物量分配,观光木幼苗的根生物量比和根冠比均随施氮量的增加而显著降低;除高氮处理外,半枫荷幼苗的根生物量比和根冠比均随供氮量的增加而显著升高;棱角山矾的根生物量比和根冠比均随供氮量的增加而显著升高,可能与施氮抑制其茎叶的生长有关。总的来看,观光木幼苗更能耐受高氮条件,半枫荷幼苗次之,而棱角山矾幼苗不耐高氮;但到当年生长季末,各氮处理半枫荷幼苗的株高、基径和总相对生长速率均显著大于其它两种植物。 相似文献
2.
氮添加对树木光合速率影响的meta分析 总被引:2,自引:0,他引:2
《生态学杂志》2017,(6)
探究氮添加对森林植物生理生态特征及生长的影响可以为探讨全球变化背景下中国森林动态变化机制及保护和管理提供依据。本文对32篇有关氮添加对植物光合作用的文献进行整合分析发现,氮添加整体上促进了树木的光合作用(10.24%),其中对温带森林树木的促进(11.45%)高于热带森林(10.32%);氮添加对阔叶树种光合速率的提高(12.16%)高于针叶树种(6.24%)。氮添加对树木光合作用的影响存在阈值效应,当氮添加量小于25 kg·hm~(-2)·a~(-1)时,光合速率略微提高(6.28%),但不显著;而随氮添加量继续增加,光合速率提高,在25~50和50~100 kg·hm~(-2)·a~(-1)氮添加条件下分别提高了13.50%和13.09%;当氮添加量超过100 kg·hm~(-2)·a~(-1)时,植物光合速率的提高则不显著。施氮时间少于5年时,氮添加显著提高植物光合速率(13.01%);施氮时间超过5年时,反而抑制植物光合速率(-20.63%);这种抑制作用在施氮时间持续10年以后则不显著。氮添加影响植物的光合速率可能是过多的氮使植物体内养分失衡(叶片N增多,P、K、Ca、Mg离子减少),而且叶绿素含量与光合酶合成和活性也随之发生变化的结果。 相似文献
3.
光照强度和氮水平对白三叶幼苗生长与光合生理特性的影响 总被引:9,自引:1,他引:9
采用植物生长箱溶液培养方式,对白三叶幼苗进行了不同光强(2个水平)和氮浓度(5个水平)处理,探讨其生长、生物量和光合生理特征对生境变化的响应.结果表明:两种光强下白三叶幼苗茎和叶生物量随氮素浓度呈先升高后降低,而根系生物量和根冠比则随氮素浓度增高而降低.光照强度降低使白三叶幼苗根、茎、叶和整株生物量分别降低67.8%、29.9%、42.5%和45.2%;低光处理使幼苗的根冠比显著下降,而比叶面积(SLA)明显提高.幼苗根系体积随氮素浓度增高而降低,高生长光强根系体积显著高于低生长光强下的白三叶.幼苗根系表面积、根系长度和根系直径随氮素浓度增加呈先增加后降低趋势,两种不同生长光强下幼苗根系长度和根系直径差异显著,而根系表面积差异不明显.白三叶叶片光合速率(Pn)随氮素浓度增加呈先增加后降低趋势,高生长光强白三叶Pn显著高于低生长光强下的白三叶.两种生长光强间叶片气孔导度(Gs),胞间CO2浓度(Ci)和蒸腾速率(Tr)无显著差异,但氮素浓度对叶片Gs、Ci和Tr均有显著影响.光、氮及其交互作用对白三叶幼苗生长发育产生了显著影响,光照不足和氮缺乏都将导致白三叶幼苗生长减弱,但幼苗对这些不利环境具有较强的调节和适应能力. 相似文献
4.
Xiang-Qin Li Sai-Chun Tang Yu-Mei Pan Chun-Qiang Wei Shi-Hong Lü 《Journal of Plant Ecology》2022,15(3):473
亚热带本地植物群落中增加降水扩大了氮增加对入侵植物表现的影响
氮沉降、降水以及它们的交互作用会影响氮和水是限制性资源的温带生态系统中的外来植物 入侵,但它们是否会影响以及怎样影响外来植物在富氮和降水丰富的亚热带植物群落中的入侵, 仍不清楚。本研究在亚热带生态系统中,在野外用12种常见本地植物构建群落,将4种入侵植物及其近缘的4种本地植物分别引入到群落中,对群落进行氮添加(0和5 g N m−2 a−1)和降水增加(自然降水和增加降水30%)交互处理,比较了引入的入侵植物和近缘本地植物在群落中的生长和定居表现以及群落特征(包括群落密度和地上生物量等)。研究结果显示,只增加降水没有提高入侵植物或近缘本地植物的表现;氮添加仅提高入侵植物地上生物量和相对密度;氮和降水同时增加提高了入侵植物和近缘本地植物在群落中的生长和定居表现。在氮添加、降水增加和氮与降水同时增加处理下,入侵植物的大多数生长和定居参数高于近缘本地植物。在氮与降水同时增加时,入侵植物所定居本地群落的密度和地上生物量显著低于近缘本地植物所定居本地群落的密度和地上生物量。这些结果说明,在富氮和降水丰富的亚热带本地群落中,降水增加扩大了氮增加对入侵植物表现的影响。这将有助于理解在富氮和降水丰富的亚热带生态系统中,全球变化对植物入侵的影响。 相似文献
5.
氮添加对长白山阔叶红松林2种树木幼苗光合生理生态特征的影响 总被引:5,自引:0,他引:5
植物的光合作用是评估全球变化背景下碳循环的重要环节。目前,氮沉降增加日益明显,作为植物生长关键因子的可利用氮将对植物的光合生理生态过程产生影响。以长白山阔叶红松林主要树种红松和紫椴的幼苗为例,通过模拟氮沉降增加(氮添加量分别为0、23、46和69 kg N hm~(-2)a~(-1))的方法,利用Li-6400光合测定系统分别测算了两个树种的最大净光合速率(A_(max))、气孔导度(G_(smax))和水分利用效率(WUE)的值,并测算了叶氮含量、叶绿素含量、比叶面积、光合氮利用效率(PNUE)的值。通过分析A_(max)随不同施氮量的变化规律,同时结合其他叶片特征参数的变化,进一步探讨植物光合随氮添加的变化原因。研究结果显示:两个树种的A_(max)值在0—46 kg N hm~(-2)a~(-1)的氮添加范围内随施氮量的增加而增大,继续增加施氮量至69 kg Nhm~(-2)a~(-1)则出现下降。叶绿素含量、G_(smax)、PNUE和比叶面积在不同的氮添加水平下的变化规律与A_(max)的一致,且均与A_(max)呈显著正相关关系。叶氮含量与A_(max)的值仅在0—46 kg N hm~(-2)a~(-1)氮添加范围内呈显著正相关。A_(max)与WUE的相关关系不显著。相同氮添加水平下,氮添加对阔叶树种紫椴各生理生态参数(A_(max)、G_(smax)、叶氮含量、比叶面积、PNUE和WUE)的促进程度高于对针叶树种红松各生理生态参数的促进程度。研究结果可为评估氮沉降增加背景下我国东北地区的碳循环提供依据。 相似文献
6.
为了探讨不同氮素形态对树木幼苗生长和光合特性影响的差异,及其对不同氮形态的适应策略,以水曲柳(Fraxinus mandshurica)和蒙古栎(Quercus mongolica)1年生幼苗为研究对象,通过盆栽试验施加硝态氮、铵态氮和有机氮,采用了双因素方差分析,确定氮素形态和树种对生长和光合指标的影响及其交互作用,采用Spearman秩相关分析生长指标和光合指标的相关性。结果表明:氮素形态处理和树种及其交互作用对幼苗的生长和生理指标的影响均达到显著水平(P<0.05),氮素形态对光合和生长的影响在2树种间存在显著差异(P<0.05)。有机氮处理组较对照组和其他氮素形态处理组更有利于蒙古栎的生长;3种氮素形态处理组的水曲柳生长指标均显著高于对照组(P<0.05),但是氮素形态处理间水曲柳的生长指标差异不显著(P>0.05)。通过对水曲柳、蒙古栎的生长和生理指标的相关性分析,发现水曲柳的光合指标间呈显著正相关关系(P<0.05),但光合指标与叶片氮质量分数的相关性不显著(P>0.05),生长指标高生长量与光合指标光补偿点、光饱和点、暗呼吸速率均呈显著... 相似文献
7.
采用添加氮素模拟氮沉降和人工气候箱模拟增温的方法,设置了对照、施氮、增温以及增温×施氮交互作用4个处理,分析不同处理对降香黄檀(Dalbergia odorifera T. Chen)幼苗生长形态变化、生物量的积累、叶片和根系生理方面的影响。结果显示:与对照相比,增温、施氮以及增温×施氮交互作用均促进了降香黄檀幼苗的生长形态发育、增加了生物量的积累、光合参数、最大光化学量子产量、叶片硝酸还原酶及根系活力,但降低了叶片相对电导率和丙二醛含量;增温×施氮交互作用下降香黄檀幼苗的生物量积累、光合参数、最大光化学量子产量、叶片硝酸还原酶及根系活力的增幅最大,而叶片相对电导率和丙二醛含量降幅最显著;隶属函数分析结果表明,增温×施氮交互作用对降香黄檀幼苗生长发育的促进效果最好,其次为单独增温,最后为施氮处理。 相似文献
8.
为阐明南亚热带4个主要树种——海南红豆(Ormosia pinnata)、马占相思(Acacia mangium)、木荷(Schima superba)和马尾松(Pinus massoniana)幼苗生长对不同氮添加量和添加方式的响应差异, 进行了幼苗模拟氮添加实验。实验设置3个氮添加水平(对照: 背景大气氮沉降量5.6 g N·m-2·a-1, 中氮: 15.6 g N·m-2·a-1, 高氮: 20.6 g N·m-2·a-1), 每个水平分两种添加方式(幼苗冠层施氮和土壤表层施氮), 共6个处理: (1)土壤对照(S-CK); (2)土壤中氮(S-MN); (3)土壤高氮(S-HN); (4)冠层对照(C-CK); (5)冠层中氮(C-MN); (6)冠层高氮(C-HN), 每个处理设置6个重复。研究结果表明: 不同氮添加量下, 土壤施氮和冠层施氮对植物幼苗生长的影响不同, 氮添加量、氮添加方式和物种3个因子之间存在显著的交互效应。与对照相比, S-MN增加了马占相思和木荷幼苗的生物量, 降低了马尾松的株高和生物量, 而C-MN仅增加了马占相思的生物量, 对其他3个树种没有影响; S-HN增加了马占相思的生物量, 显著降低了马尾松的基径、株高和生物量(p < 0.01), C-HN增加了马占相思、木荷和马尾松的基径、株高和生物量(p < 0.01)。不同氮添加量和氮添加方式对幼苗生长的影响因物种而异, 所有氮处理下海南红豆和马占相思的生长均明显快于木荷和马尾松; 木荷和马尾松幼苗的生长在两种氮添加方式间差异显著, 冠层施氮比土壤施氮对其幼苗生长的促进作用更大。由此可见: 在氮沉降背景下, 阔叶豆科植物(海南红豆、马占相思)比阔叶非豆科植物(木荷)生长快; 阔叶树种(海南红豆、马占相思和木荷)比针叶树种(马尾松)生长快。在长期氮沉降环境下, 不同物种生长的差异响应有可能导致亚热带森林物种组成发生变化。 相似文献
9.
氮沉降对植物群落的影响,特别是对脆弱生态系统中植物群落的影响,一直是生态学研究的热点问题。为了更好地探究氮沉降对脆弱生态系统植物群落不同功能群生理生态特征的影响,以青藏高原高寒草甸为研究对象,将植物群落划分为禾本科、莎草科、杂类草3种不同功能群,通过模拟氮沉降试验,观测不同氮添加水平下(0、8、24、40、56、72kg·hm~(-2)·a~(-1)) 3种功能群数量特征和净光合速率的动态变化,以期揭示植物对氮沉降的响应规律。结果显示:1)氮添加对不同功能群植物数量特征的影响具有显著差异,氮添加提高了莎草科的多度和高度,而对禾本科和杂类草的多度和高度无显著影响(P0.05),禾本科的地上生物量随着氮添加水平的升高表现出先下降后上升的变化趋势,而莎草科和杂类草的地上生物量随着氮添加水平的升高均表现出下降趋势; 2)氮添加对不同功能群植物光合作用的影响有显著差异,禾本科的净光合速率(P_n)随着氮添加水平的升高表现出先下降后上升的变化趋势,而莎草科和杂类草净光合速率均表现出线性下降趋势,氮添加显著提高了不同功能群植物的气孔导度(G_s)和蒸腾速率(T_r)。3)三个功能群植物的净光合速率与地上生物量之间均呈显著正相关。研究表明,短期高氮添加会削弱植物的光合能力,降低植物地上生物量的积累,抑制植物生长。 相似文献
10.
施肥对香樟幼苗生长及养分分配的影响 总被引:1,自引:0,他引:1
施肥是苗木培育的重要方式,香樟是乡土珍稀阔叶树种,苗木培育对乡土珍稀树种的保护、繁育、推广具有极其重要的作用,施肥对苗木的生长和发育具有重要的影响。因此,为了探讨香樟幼苗生长及植物体内养分分配对施肥的响应,该研究采用正交设计,设置了氮、磷、钾3因素3水平(N、P:0、3、6 g·株-1;K:0、2、4g·株-1),对盆栽香樟幼苗进行指数施肥。结果表明:(1)氮肥对香樟幼苗苗高、地径、生物量的影响最为显著,磷肥和钾肥的影响则较小;(2)氮素在香樟幼苗叶、茎、根中的分布状况主要受氮肥的影响,磷素在香樟幼苗叶、茎、根中的分布状况主要受氮肥和磷肥的影响,钾素在香樟幼苗叶、茎、根中的分布状况主要受钾肥的影响;(3)香樟幼苗的苗高生长与叶片氮含量、叶片磷含量呈显著正相关(P0.05),地径生长与茎氮含量呈显著正相关(P0.05),叶生物量与叶片氮含量、叶片磷含量呈显著正相关(P0.05),茎生物量与叶片磷含量呈显著正相关(P0.05);(4)综合分析得出,对香樟幼苗苗高、地径生长,以及枝叶生物量积累最具促进作用的施肥水平为氮肥(6 g·株-1)、磷肥(6 g·株-1)、钾肥(4 g·株-1)。 相似文献
11.
Lawrence A. Pervin 《Human ecology: an interdisciplinary journal》1978,6(1):71-105
A review is presented of issues relevant to the definition, measurement, and classification of stimuli, situations, and environments. Problems such as the lack of adequate definitions of concepts, error and bias in measurement procedures, confusion between measurement of a concept and measurement of its behavioral effects, and the lack of agreement among alternative measures are emphasized. It is suggested that concepts be defined in terms of objective characteristics while allowing for the study of the transactional relationship between organism and environment. The work of the ethologists in defining stimuli while studying their relationship to different organismic states and situational contexts is emphasized in this regard. Following Brunswik, it is also suggested that wherever possible there be a representative sampling of variables in natural settings.
Note from the editors: From time to time, Human Ecology will publish a review article. Our first in this series is a review by a psychologist of basic definitional and conceptual problems in environmental studies.This paper was prepared while the author was a Visiting Research Fellow at the Educational Testing Service. The support of ETS and my colleagues in the Division of Psychological Studies is gratefully acknowledged. The review was also supported in part by a grant from the Rutgers University Research Council. 相似文献
12.
2-Dimethylaminomethylene-1-benzosuberone 1 was coupled with diazotized aniline derivatives to afford a series of the hitherto unreported 2-arylazo-1-benzosuberones 3a–i. The tautomeric structure and the effect of substituents on the tautomeric form (s) of the products 3a–i were discussed. Similar coupling of the enaminone 1 with diazonium salts of heterocyclic amines gave the respective fused azolotriazino-benzosuberones. Some of the newly synthesized compounds showed potent antimicrobial, anti-HCV, antioxidant, antitumor (as topoisomerase I inhibitors), and antimicrobial activities. 相似文献
13.
14.
Acute and chronic toxicity tests for malathion, diazinon, copper (Cu), mercury (Hg), lead (Pb), zinc (Zn), nickel (Ni), and
iron (Fe) were conducted. Mortalities ofBarilius vagra andCyprinus carpio (common carp) were variable but LC50-96 hr were similar for pesticides. AdultB. vagra seem to be more sensitive to malathion than juvenile carp. Both juvenile carp and adultB. vagra were extremely sensitive to diazinon. Long-term exposure to pesticides modified morphology and behavior. The LC50-96 values
for Cu, Hg, and Pb were 0.3, 0.16, and 0.44, respectively, for smaller fish and 1.0, 0.77, and 1.33, respectively, for larger
fish. Replicate LC50 values for Zn, Ni, and Fe were somewhat variable, and for these metals, the size of the fish seemed to
affect response because LC50 values increased as fish size increased. Cooper, Pb, Zn, and Fe residues following exposure to
sublethal concentrations of these metals for 15 d were significantly greater in whole juvenile common carp than in controls. 相似文献
15.
Low-frequency dynamics and Raman scattering of crystals, of B-, A-, and Z-DNA, and fibers of C-DNA 总被引:1,自引:0,他引:1
Normal modes of vibration of DNA in the low-frequency region (10-300 cm-1 interval) have been identified from Raman spectra of crystals of B-DNA [d(CGCAAATTTGCG)], A-DNA [r(GCG)d(CGC) and d(CCCCGGGG)], and Z-DNA [d(CGCGCG) and d(CGCGTG)]. The lowest vibrational frequencies detected in the canonical DNA structures--at 18 +/- 2 cm-1 in the B-DNA crystal, near 24 +/- 2 cm-1 in A-DNA crystals, and near 30 +/- 2 cm-1 in Z-DNA crystals--are shown to correlate well with the degree of DNA hydration in the crystal structures, as well as with the level of hydration in calf thymus DNA fibers. These findings support the assignment [H. Urabe et al. (1985) J. Chem. Phys. 82, 531-535; C. Demarco et al. (1985) Biopolymers 24, 2035-2040] of the lowest frequency Raman band of each DNA to a helix mode, which is dependent primarily upon the degree of helix hydration, rather than upon the intrahelical conformation. The present results show also that B-, A-, C-, and Z-DNA structures can be distinguished from one another on the basis of their characteristic Raman intensity profiles in the region of 40-140 cm-1, even though all structures display two rather similar and complex bands centered within the intervals of 66-72 and 90-120 cm-1. The similarity of Raman frequencies for B-, A-, C-, and Z-DNA suggests that these modes originate from concerted motions of the bases (librations), which are not strongly dependent upon helix backbone geometry or handedness. Correlation of the Raman frequencies and intensities with the DNA base compositions suggests that the complex band near 90-120 cm-1 in all double-helix structures is due to in-plane librational motions of the bases, which involve stretching of the purine-pyrimidine hydrogen bonds. This would explain the centering of the band at higher frequencies in structures containing G.C pairs (greater than 100 cm-1) than in structures containing A.T pairs (less than 100 cm-1), consistent with the strengths of G.C and A.T hydrogen bonding. 相似文献
16.
17.
Synthesis and properties of N-, O-, and S-phospho derivatives of amino acids, peptides, and proteins
A W Frank 《CRC critical reviews in biochemistry》1984,16(1):51-101
The literature on chemical (i.e., nonenzymic) phosphorylation of amino acids, peptides, and proteins is reviewed through 1982. The review covers synthetic methods, chemical reactions, and physical properties, with emphasis on the techniques used for separation and characterization of the products. Synthetic methods are classified by reagent rather than product, and are illustrated by experimental procedures for the most important methods. Chemical reactions are classified into four groups depending on whether the reaction site is the phospho group, the amino group, the carboxyl group, or in the case of serine the hydroxyl group. Physical data are given for all of the known N-, O-, and S-phospho derivatives of the amino acids, peptides, and proteins, within certain limitations, and are discussed in detail in the section on physical properties. Emphasis is given to the techniques used for separation of the products, such as chromatography and electrophoresis, and for characterization of the products, particularly spectroscopy. Medical and other uses of the products are mentioned. 相似文献
18.
Cultural, Biochemical, and Immunological Properties of Mima, Herellea, and Flavobacterium Species 总被引:5,自引:4,他引:1
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From study of cultural and biochemical characteristics of 40 strains of Herellea, Mima, or Flavobacterium species, a proposed schema for identification was developed. The reactions observed by agglutination, gel diffusion, and immunofluorescence suggest antigenic heterogeneity of this group of organisms. 相似文献
19.
Studies that have examined pet loss hypothesize that attachment, representations of death, and the belief in an afterlife for animals may influence owners’ bereavement and depressive outcomes. The following instruments were administered to 159 Italian participants recruited through snowball sampling: the Lexington Attachment to Pets Scale (LAPS), the Pet Bereavement Questionnaire (PBQ), the Testoni Death Representation Scale (TDRS), and Beck’s Depression Inventory II (BDI-II). Questions concerning pet euthanasia-related issues and the relationship between owners and veterinarians were also submitted to the participants. A path model was conducted, showing that the representation of death and the attachment to a pet had a direct effect on pet grief, which in turn had a direct effect on depression. The results show a positive correlation between the LAPS and PBQ factors, particularly with the PBQ factor Grief. The LAPS factors positively correlated with the TDRS representation of Death as a Passage and negatively correlated with the TDRS representation of Death as Annihilation. The LAPS People Substituting factor positively correlated with the total score and the Cognitive-Affective factor of the BDI-II. The PBQ factors positively correlated with the BDI-II, whereas only the TDRS Death as Annihilation factor positively correlated with the BDI-II. Belief in a transcendent dimension was associated with higher scores on the PBQ Guilt factor and the TDRS factors of Death as a Passage and Death as Change, whereas these beliefs were associated with lower scores on the TDRS factor Death as Annihilation.
The results indicated that the sensitivity of the veterinarian and a veterinarian who helps owners make conscious and informed decisions for their pet and choose the right time to perform euthanasia are important variables in the management of pet loss. However, these factors are not sufficient and psychological support should be improved to help owners better cope with grief. 相似文献
20.
Schmidt BR 《Comptes rendus biologies》2003,326(Z1):S119-S124
The evidence for amphibian population declines is based on count data that were not adjusted for detection probabilities. Such data are not reliable even when collected using standard methods. The formula C = Np (where C is a count, N the true parameter value, and p is a detection probability) relates count data to demography, population size, or distributions. With unadjusted count data, one assumes a linear relationship between C and N and that p is constant. These assumptions are unlikely to be met in studies of amphibian populations. Amphibian population data should be based on methods that account for detection probabilities. 相似文献