Dieback intensity but not functional and taxonomic diversity indices predict forest productivity in different management conditions: Evidence from a semi-arid oak forest ecosystem     

Mona KARAMI  Mehdi HEYDARI  Ali SHEYKHOLESLAMI  Majid ESHAGH NIMVARI  Reza OMIDIPOUR  YUAN Zuoqiang  Bernard PREVOSTO 《干旱区科学》2022,14(2):225-244

The relationships between different aspects of diversity(taxonomic,structural and functional)and the aboveground biomass(AGB)as a major component of global carbon balance have been studied extensively but rarely under the simultaneous influence of forest dieback and management.In this study,we investigate the relationships between taxonomic,functional and structural diversity of woody species(trees and shrubs)and AGB along a gradient of dieback intensity(low,moderate,high and no dieback as control)under two contrasted management conditions(protection by central government vs.traditional management by natives)in a semi-arid oak(Quereus brantii Lindl.)forest ecosystem.AGB was estimated and taxonomic diversity,community weighted average(CWM)and functional divergence indices were produced.We found that the aerial biomass was significantly higher in the intensively used area(14.57(±1.60)t/hm²)than in the protected area(8.70(±1.05)t/hm²)due to persistence of some large trees but with decreasing values along the dieback intensity gradient in both areas.CWM of height(H),leaf nitrogen content(LNC)and leaf dry matter content(LDMC)were also higher in the traditional managed area than in the protected area.In contrast,in the protected area,the woody species diversity was higher and the inter-specific competition was more intense,explaining a reduced H,biomass and LDMC.Contrary to the results of CWM,none of the functional diversity traits(FDvar)was affected by dieback intensity and only FDvar values of LNC,leaf phosphorus content(LPC)and LDMC were influenced by management.We also found significantly positive linear relationships of AGB with CWM and FDvar indices in the protected area,and with taxonomic and structural diversity indices in the traditional managed area.These results emphasize that along a dieback intensity gradient,the leaf functional traits are efficient predictors in estimating the AGB in protected forests,while taxonomic and structural indices provide better results in forests under a high human pressure.Finally,species identity of the dominant species(i.e.,Brant’s oak)proves to be the main driver of AGB,supporting the selection effect hypothesis.  相似文献   

茭白冷藏期间蛋白质表达谱的变化   总被引：2，自引：1，他引：1  

罗海波  姜丽  包永华  张丽  石韵  郁志芳 《农业工程学报》2014,30(1):285-292

为探讨茭白冷藏期间衰老的分子机理,应用蛋白质组学技术,研究了茭白冷藏期间蛋白质表达谱的变化。结果显示,双向电泳胶上共检测到大约650个蛋白点,其中35个蛋白表达量存在2.0倍以上显著(p0.05)差异,经过串联飞行时间质谱分析,成功鉴定出29个蛋白,根据其功能可分为6类,即代谢(20.7%)、细胞结构(27.6%)、抗胁迫(20.7%)、衰老(6.9%)、蛋白质合成(13.8%)和功能未知蛋白(10.3%);其中:代谢相关蛋白3个上调表达、3个下调表达,细胞结构相关蛋白6个上调表达、2个下调表达,抗胁迫相关蛋白4个上调表达、2个下调表达,衰老相关蛋白2个上调表达,蛋白质合成相关蛋白4个及功能未知蛋白3个均下调表达。这些差异表达蛋白的功能分析表明,茭白采后衰老机理可能涉及物质代谢过程的调整、能量代谢途径的改变、活性氧清除能力的减弱以及细胞结构的解体。  相似文献   

淹水胁迫下小麦根通气组织形成的PCD特征及活性氧作用初探     

邓祥宜  李继伟  阳超男  姜珍  肖诗鑫  周竹青 《麦类作物学报》2009,29(5):832-838

为了解淹水条件下小麦根通气组织形成的细胞学特点和活性氧(Reactive oxygen species, ROS)在通气组织形成中的作用,以高度耐湿的华麦8号幼苗为材料进行淹水处理,在显微水平上系统地观察了通气组织的形成过程,在分子水平上检测了细胞核DNA的断裂情况,并对ROS的动态变化进行了荧光观察.结果表明:(1)通气组织最先起源于根皮层中部,然后逐渐扩展,到淹水8 d时基本形成,淹水60 d时更为发达;(2)淹水1.5～48 h根皮层出现大量细胞核DNA断裂,且细胞核DNA降解为180～200 bp的片段,证明小麦根通气组织的形成过程是根皮层细胞发生细胞程序化死亡(Programmed cell death, PCD)的过程,而且淹水1.5～48 h是根皮层细胞死亡高峰期;(3)ROS在细胞核DNA发生断裂前开始积累,在通气组织形成中呈现动态变化.上述结果表明, 淹水胁迫下小麦根通气组织形成是一个皮层细胞PCD的过程,并且ROS可能参与介导了PCD的进程.另外,淹水胁迫在前期抑制了次生根的产生,随后又促进了次生根的产生.  相似文献   

拟南芥模拟病斑突变体的研究进展     

韩成云  黄颖  洪亚辉  任春梅 《湖南农业科学》2008,(6)

从细胞程序化死亡角度综述了拟南芥模拟病斑突变体的研究进展。植物模拟病斑突变体在没有明显的逆境、损伤或病原物侵害时,能自发地形成坏死斑,并可能增强植物的抗病性。对模拟病斑突变体的研究有助于深入探讨植物细胞发育与凋亡、植物防御和抗病机制等。  相似文献   

花药绒毡层细胞程序性死亡研究进展   总被引：5，自引：0，他引：5  

张虹  梁婉琪  张大兵 《上海交通大学学报(农业科学版)》2008,26(1):86-90

绒毡层作为花药壁最内层的特殊体细胞,与小孢子母细胞以及花药发育后期的小孢子直接相互作用,在花粉发育过程中起着至关重要的作用。花药绒毡层发育到一定阶段,绒毡层细胞需要经过一个细胞程序性死亡的降解过程为小孢子的发育提供营养和物质保证,而且绒毡层细胞降解的提前或者延迟都将导致雄性不育。近年来人们利用分子生物学手段已相继克隆到了一些与绒毡层细胞程序性死亡相关的基因,使人们对绒毡层的降解机制有了更深入的认识。本文旨在综述花药绒毡层细胞程序性死亡特征及其调控机制研究的最新进展。  相似文献   

植物抗病过程中的细胞程序性死亡   总被引：1，自引：0，他引：1  

王媛  梁军  张星耀 《林业科学》2008,44(2):143-149

细胞程序性死亡是由某些特定基因调控的,在细胞生长发育或对外界刺激的反应过程中表现出来的一种生物学过程,伴随着细胞形态学及分子生物学等方面的特征.其中,植物过敏性反应是细胞程序性死亡的重要表现形式之一,表现为植物在不亲和病原菌侵染下受侵细胞及邻近细胞的快速死亡,从而导致病原菌生长受抑制,HR过程对于植物抗病性有重要意义.目前,关于抗病过程中的PCD和HR的研究已成为植物病理学的重点和热点之一.本文综述了植物抗病过程中PCD及HR的研究进展,重点对植物HR特征、可能的信号传导因子、检测方法、产生的分子机制等方面进行了分析和总结,并对林木抗病中的PCD研究进行了展望.  相似文献   

Cytological study and PCD assay on pollen development of photoperiod sensitive genic male sterile rice     

Sha Zhao  Jialing Yao 《Frontiers of Agriculture in China》2008,2(2):150-155

A systematic cytological comparison of the anther development of photoperiod sensitive genic male sterile (PSGMS) rice with its normal fertility counterpart was conducted. The results showed that pollen abortion in PSGMS rice occurred first no later than the pollen mother cell (PMC) stage and continued during the entire process of pollen development till pollen degradation. This abortive process was closely associated with the abnormal behavior of tapetum. Although tapetum degeneration in the PSGMS rice initiated as early as at the PMC stage, it proceeded slowly and did not complete until the breakdown of the pollen, in sharp contrast to the rapid disintegration of the tapetal layer during the late microspore to the bicellular pollen stage in the fertile rice. Such cytological observation was supported by the results of the TUNEL (TdT2 mediated dU TP Nick End Labeling) assay that detectsDNA fragmentation resulting from programmed cell death (PCD), indicating that the tapetum degeneration occurs in the process of PCD. __________ Translated from Journal of Huazhong Agricultural University, 2007, 26(3): 283–288 [译自: 华中农业大学学报]  相似文献   

卡夫卡与陈染的语象比较     

马英 《信阳农业高专学报》2008,18(1):94-95

陈染和卡夫卡的艺术世界都是关闭的,“向内性”是两人作品的共同特点,表现了现代人孤独的自我意识,显示出现代人在思想和主体意识等方面的共鸣。  相似文献   

Establishment,survivorship, and growth of yellow birch seedlings after site preparation treatments in large gaps     

François Lorenzetti  Sylvain Delagrange  Daniel Bouffard  Philippe Nolet 《Forest Ecology and Management》2008

The occurrence of yellow birch (YB) in the northeastern forests of North America is a source of concern. Several guidelines suggest ways to favor the regeneration of this species, including creating openings from small gaps to large clearcuts, coupled or not with a variety of soil preparation treatments. However, it is not clear if soil preparation treatment favors YB establishment by simply increasing the availability of good seedbed types, or by also altering competition pressure exerted by interfering species during the period of seedling establishment. For this study, large gaps (900 m²) were created in a 70-year old YB dominated forest, to which three treatments differing in soil disturbance intensities were applied (i.e., soil scarification (i) using a rake [raking]; or (ii) by dragging slash out to the edges of the gap [slash drag]; and (iii) limited to the passage of the harvesting equipment [control]). The proportion of seedbed types reportedly most favorable for YB establishment (i.e., mineral-dominated) increased as the severity of the site preparation increased. The opposite was observed for organic-dominated seedbeds. As a result, the stocking of YB seedlings increased with the severity of site preparation. However, YB stocking was deemed sufficient in all gaps to ensure future canopy dominance, even in the control treatment. Although YB seedlings generally achieved greater heights as site preparation intensity increased, it was clear that this did not reflect vigorous growth as, on average, greater heights coincided with greater seedling height–diameter ratios. At the seedbed level, height–diameter ratio was associated with an increase in surrounding competition pressure and an increase in the incidence of stem apical death (SAD), which in turn decreased height differences among seedbed types by the end of the study. At the gap level, this blurred the advantages of site preparation over a laisser-faire strategy. The incidence of SAD was greatest in the slash drag and the rake treatments. Consequently, we cannot say that intense soil scarification is worth the expenses, especially in stands where YB seed sources are abundant.  相似文献   

Susceptibility of Iberian trees to Phytophthora ramorum and P. cinnamomi     

E. Moralejo  J. A. García-Muñoz  E. Descals 《Plant pathology》2009,58(2):271-283

The capacity of Phytophthora ramorum to colonize the inner bark of 18 native and two exotic tree species from the Iberian Peninsula was tested. Living logs were wound-inoculated in a growth chamber with three isolates belonging to the EU1 and two to the NA1 clonal lineages of P. ramorum . Most of the Quercus species ranked as highly susceptible in experiments carried out in summer, with mean lesion areas over 100 cm² in Q. pubescens , Q. pyrenaica , Q. faginea and Q. suber and as large as 273 cm² in Q. canariensis , ca . 40 days after inoculation. Quercus ilex ranked as moderately susceptible to P. ramorum , forming lesions up to 133 cm² (average 17·2 cm²). Pinus halepensis and P. pinea were highly susceptible, exhibiting long, narrow lesions; but three other pine species, P. pinaster , P. nigra and P. sylvestris , were resistant to slightly susceptible. No significant difference in aggressiveness was found between the isolates of P. ramorum . In addition, there was evidence of genetic variation in susceptibility within host populations, and of significant seasonal variation in host susceptibility in some Quercus species. The results suggest a high risk of some Iberian oaks to P. ramorum , especially in forest ecosystems in southwestern Spain, where relict populations of Q. canariensis grow amongst susceptible understory species such as Rhododendron ponticum and Viburnum tinus . One isolate of P. cinnamomi used as positive control in all the inoculations was also highly aggressive to Iberian oaks and Eucalyptus dalrympleana .  相似文献