【摘 要】
:
Background:Carbon (C),nitrogen (N),and phosphorus (P) stoichiometry is a key indicator of nutrient utilization in plants,and C/N/P ratios are related to the life histories and adaptation strategies of tree species.However,no consensus has been reached on
【机 构】
:
Fujian Provincial Key Laboratory for Plant Eco-physiology,Fujian Normal University,Fuzhou,350007,Chi
论文部分内容阅读
Background:Carbon (C),nitrogen (N),and phosphorus (P) stoichiometry is a key indicator of nutrient utilization in plants,and C/N/P ratios are related to the life histories and adaptation strategies of tree species.However,no consensus has been reached on how leaf stoichiometric characteristics are affected by forest type and stand ages.The relationships between leaf stoichiometry and geographical,meteorological,and soil factors also remain poorly understood.Methods:Leaf and soil were sampled from forest stands of different age groups (young,middle-aged,near-mature,and mature) in two forest types (Chinese fir (Cunninghamia lanceolata) forests and evergreen broadleaved forests).The relationships between leaf C,N,and P stoichiometric parameters and geographical,meteorological,and soil factors were analysed by using redundancy analysis (RDA) and stepwise linear regression analysis.Results:Leaf C concentrations peaked in the near-mature stands with increasing age irrespective of forest type.Leaf N and P concentrations fluctuated with a rising trend in Chinese fir forests,while decreased first and increased later from young to mature phases in natural evergreen broadleaved forests.Chinese fir forests were primarily limited by N and P,while natural evergreen broadleaved forests were more susceptible to P limitation.Leaf C,N,and P stoichiometric characteristics in Chinese fir forests were mainly affected by the soil total P concentration (SP),longitude (LNG),growing season precipitation (GSP) and mean temperature in July (JUT).The leaf C concentration was mainly affected by GSP and JUT;leaf N and P concentrations were both positively correlated with LNG;and leaf P was positively correlated with SP.In evergreen broadleaved forests,however,leaf stoichiometric parameters displayed significant correlations with latitude (LAT) and mean annual precipitation(MAP).Conclusions:Leaf stoichiometry differed among forest stands of different age groups and forest types.Leaf C,N,and P stoichiometry was primarily explained by the combinations of SP,LNG,GSP and JUT in Chinese fir forests.LAT and MAP were the main controlling factors affecting the variations in the leaf C,N,and P status in natural evergreen broadleaved forests,which supports the temperature-plant physiological hypothesis.These findings improve the understanding of the distribution patterns and driving mechanisms of leaf stoichiometry linked with stand age and forest type.
其他文献
[目的]我国主栽苹果品种根据亲本构成可分为富士族系、元帅族系、金冠族系和国光族系,分析不同族系果实的香气特征和遗传特性,为果品品质研究和香气育种提供参考.[方法]采取固相微萃取和气相色谱质谱(SPME-GC-MS)联用技术对4个族系的50个苹果品种果实香气物质进行检测,利用变异系数(CV)和主成分分析(PCA)解析不同族系间香气物质的显著性和特征.[结果]50个品种共检测出146种香气成分,酯类(38种)、醛类(29种)和醇类(19种)为主要香气物质,共占总含量的72.82%,其中酯类在数量和含量上变异系
[目的]研究长期施氮对酸性紫色土壤中氨氧化古菌(AOA)和氨氧化细菌(AOB)群落特征的影响,揭示氨氧化微生物群落的驱动因子及其调控硝化作用的微生物学机制.[方法]依托四川雅安玉米体系施氮长期定位试验(始于2010年),试验处理包括5个供氮水平,即0(N0)、90(N90)、180(N180)、270(N270)和360(N360)kg N·hm-2,通过Illumina Miseq高通量测序技术测定AOA和AOB的群落,探究长期施氮对氨氧化微生物群落介导的硝化作用的影响.[结果]长期施氮影响AOA和AO
Background:The recent rise in temperature and shifting precipitation regimes threaten ecosystems around the globe to different degrees.Treelines are expected to respond to climate warming by shifting to higher elevations,but it is unclear whether they can
Background:Global climate change,characterized by changes in precipitation,prolonged growing seasons,and warming-induced water deficits,is putting increased pressure on forest ecosystems globally.Understanding the impact of climate change on drought-prone
早稻育秧期间低温频发,严重影响水稻秧苗质量,抑制水稻在大田期间的生长发育,导致水稻减产.深入研究低温对水稻生长发育的影响及适宜的外源调控途径对保障我国早稻生产具有重要意义.本文综述了低温对早稻秧苗期、营养生长期与生殖生长期的影响,概括了水稻响应低温胁迫的生理、生化和分子机制,包括抗氧化系统、低温应答基因表达等.最终提出了运用耐低温水稻品种筛选、外源激素施加和合理施肥等提高水稻耐低温胁迫的措施,并指出未来应加强筛选优良抗寒水稻品种和集成农艺栽培配套技术等措施提高水稻低温耐性和扩大我国早稻面积.
[目的]为阐明无人机与地面植保机械喷施雾滴在水稻冠层的沉积分布特征,比较其对不同冠层病虫害防治效果,科学推广及使用植保机械.[方法]采用雾滴沉积分布检测、利用率测定以及田间调查等方法,研究6种不同植保机械在水稻田喷雾后雾滴在冠层的沉积分布、利用率以及对纹枯病和稻纵卷叶螟的防治效果.[结果]3种无人飞机喷施雾滴在水稻冠层的沉积密度和覆盖率差异显著,在冠层上部的沉积量较其他3种地面植保机械高,但在下部的沉积量低.不同植保机械在冠层上、中、下层的沉积密度、覆盖率以及沉积量均呈递减趋势.施药后14 d,3种无人机
Background:Volcanic eruptions have large effects on forest ecosystems and create new substrates,triggering primary succession processes.The Paricutín volcano,born in central-western Mexico,erupted between 1943 and 1952.After the cessation of the eruptive
[目的]研究水稻EARLY STARVATION1(OsESV1)基因对水稻淀粉代谢的影响.[方法]通过CRISPR-Cas9技术获得osesv1突变体,考查osesv1的表型及胚乳淀粉的理化特性,分析OsESV1的表达特性及相关功能.[结果]OsESV1蛋白在植物界中十分保守.osesv1突变体株高、穗长、每穗粒数低于野生型,分蘖数显著多于野生型,叶片中淀粉含量显著下降,籽粒中的直链淀粉含量上升,而总淀粉含量无明显变化.OsESV1呈组成型表达,并且具有昼夜节律表达的特征.OsESV1蛋白定位在叶绿体内
Background:Cork oak agroforestry systems (AFS) have been managed for centuries by humans to produce cork and other goods and services and have recently been recognised as an important reservoir for biodiversity improvement and conservation.However,despite
[目的]研究抗倒酯对优质稻抗倒伏能力及产量与米质的影响.[方法]以优质稻品种丰锦和沈农09001为试材,在分蘖期、拔节初期、孕穗期叶面喷施不同浓度(0、90、180和360 mg/L,1200 L/hm2)的抗倒酯,以倒伏指数、抗折力以及抗推力作为评价植株抗倒伏能力的指标,研究抗倒酯对优质稻抗倒伏能力及产量和米质的影响.[结果]施用抗倒酯可以改善水稻茎秆的形态和解剖结构,提高植株抗倒伏能力.随着施用浓度的增加,株高降低,重心下移,基部第1、2、3节间长度缩短,茎秆粗度及茎壁厚度增加,大、小维管束数目、大维