茶树根系生长及其影响因子研究进展

本文主要综述茶树根系的结构、特点、功能与生长营养特性,以及近些年来影响和调控茶树根系生长的非生物和生物因子的研究进展,并对进一步研究进行展望。     

影响真菌漆酶表达及其活性的因素

丝状真菌同一菌株中存在动力学、理化特性各异的多个漆酶同工酶。金属离子,碳、氮等培养基成分,培养条件,以及异生物质、热休克处理和共培养的菌株等多种生物和非生物的因素对真菌漆酶同工酶表现出选择性诱导效应。影响真菌漆酶表达及其调控因素的研究能指导漆酶的选择性合成,以满足不同的应用需求。主要阐述影响真菌漆酶表达及其活性的因素的相关研究进展。     

Regulation of Asexual Reproduction of the Planarians Dugesia tigrina

We studied asexual reproduction of planarians under the natural and artificial photoperiodic conditions. It was shown that light inhibits the fission of planarians, while darkness stimulates it. The diurnal dynamics of the fission of planarians demonstrated a circadian rhythm. This rhythm is stable, which is expressed when the conditions are experimentally changed: constant darkness, unnatural rhythm of light-darkness succession). However, this stability is affected at the time zone change. The planarians are adapted to new conditions and begin to fission at once in correspondence with the new diurnal regime.     

植被原生演替研究进展

对植被原生演替的国内外研究进展进行了评述。植被原生演替过程受到生物因素和非生物因素的共同影响。生物因素包括种子的传播方式、对原生环境的适应能力及物种之间的关系等,依靠风力传播、对裸地的极端环境具有较强适应能力的物种更容易成为原生裸地的早期定居者,某些微生物在植物的定居具有非常重要的作用。非生物因素则包括裸地表面的形状(凹、凸、平)、粗糙度、与岩石的距离等,一些特殊的微环境能够为植物的定居创造更为优越的水分、养分条件,促进植物的定居。植被原生演替是生物驱动因素与环境阻力相互作用的结果,二者的消长决定原生演替进行的模式。大量的研究表明,植被原生演替过程并不完全遵循地衣-苔藓-草本植物-木本植物的顺序,不同环境条件下的植被原生演替过程表现出明显的复杂性,这种复杂性与原生裸地环境条件的复杂性有关。该领域的研究将侧重于以下两个方面:早期定居种的适生特征(包括解剖的和生理的)以及各种微生物对植物定居过程的影响;各种非生物环境因素对植物定居的影响。     

Calcium as a limiting resource to insectivorous bats: can water holes provide a supplemental mineral source?

Data are presented on a bat assemblage captured among 10 water holes in Colorado over 5 years. The assemblage consists of Myotis ciliolabrum , M. evotis , M. lucifugus , M. thysanodes , M. volans , Eptesicus fuscus , Lasiurus cinereus , Lasionycteris noctivagans and Corynorhinus townsendii . Results show that reproductive females and juveniles are captured in higher frequencies at water holes containing higher water hardness and that water hardness correlates highly significantly with dissolved calcium content. Also presented are laboratory test data on the stomach volume of Eptesicus fuscus that provide a model for understanding the effect of dissolved calcium content in water as a significant resource. These data indicate that water holes provide supplemental sources of calcium for bats not provided by diet.     

黄土高原地区森林生态系统地下生物量影响因素

根系将土壤和大气相连与植物体共同影响生态系统的碳循环,同时根系也是森林生态系统土壤碳库的重要来源。研究表明森林地下生物量受生物因素和非生物因素影响,因此研究各因素对根系生物量的影响对精确估算土壤碳库至关重要。基于我国相关部门的观测及调查数据,通过标准化计算和统计分析来量化各因素对黄土高原地区地下生物量的影响。结果表明：黄土高原森林生态系统地下生物量主要分布在11.99-27.46 Mg/hm²之间;非生物因素对地下生物量起主导作用,其中降雨量和地形影响最为显著;不同土壤类型地下生物量表现出：棕壤 > 褐土 > 岩性土;不同森林类型地下生物量大小为：针叶林 > 针阔叶混交林 > 落叶阔叶林;不同地形地下生物量由大到小为：丘陵、山地 > 高原、平原;地下生物量在坡位上的分布大小为：坡麓 > 上、中、下三个坡位 > 平地;人类活动和动物活动干扰对地下生物量的影响没有显著差异。另外,在分析中发现若影响因素中含经纬度,非生物和生物因素对地下生物量的影响程度分别为68.9%和31.1%;若影响因素中不含经纬度,非生物和生物因素对地下生物量的影响程度分别为81.1%和18.9%,说明经纬度与其他因素存在很强的相关性,并严重影响着生物因素和非生物因素对森林生态系统地下生物量的比重。研究结果对地下生物量的估测有一定的意义,可以为森林植被如何通过根系适应环境的研究提供参考,为植被恢复、森林经营管理及地下部分碳循环的研究提供依据。     

Arabinogalactan proteins: actors or spectators during abiotic and biotic stress in plants?

Arabinogalactan proteins (AGPs) are a family of hydroxyproline-rich glycoproteins (HRGP) ubiquitous in the plant kingdom. They are probably one of the most heterogeneous and complex families of macromolecules, making them able to perform different and multiple functions. Located at the plasma membrane–cell wall interface, AGPs are involved in several processes, from plant growth and development to reproduction. An additional function of AGPs in response to biotic and abiotic stress has been suggested by several studies. The purpose of this review is to summarize critically and analytically the available knowledge on the effects of abiotic stress (low and high temperatures, drought, flooding, anoxia and metal deficiency/toxicity) and biotic stress (bacteria, fungi, nematodes and viruses) on AGPs. A deeper understanding of the role of AGPs during these conditions can be an important tool for understanding AGP biology and for the possible development of efficient breeding strategies.     

采石场废弃地的生态重建研究进展

采石场的开采严重破坏了植被和土壤,形成了大量的裸露岩石斜坡,造成宏观景观支离破碎和极端的环境条件,限制了植物的生长。由于自然恢复所需时间长久,人工恢复被广泛应用于采石场废弃地的生态重建。自然演替过程是采石场生态重建的理论基础,自然演替理论可以为人工恢复措施提供指导。植物群落演替的早期阶段,非生物因素起主要作用,随着演替的推移,生物因素的重要性增强。邻近自然植被的土壤和繁殖体通过外力的扩散,对恢复起重要作用。除了非生物和其他的限制,先到达恢复地的物种竞争能力的变化能决定了演替过程。演替过程中的干扰因素往往成为演替重要的驱动力。裸露岩石斜坡的物理稳定性对植被恢复有重要影响,有机废物的使用和施肥可以影响恢复演替的方向和生物多样性。播种一定的植物能够改变恢复演替方向,加速演替过程。乡土物种适应了当地气候,能够促进演替。随着修复时间的延长,土壤有机质含量,植被覆盖度和物种丰富度不断增加,土壤微生物生物量随之增加。开展不同地区采石场植物种类的选育、研究乡土物种的功能特性、土壤微生物群落和酶的变化、植被演替过程的定位研究、植物种间的竞争关系、自然演替和人工恢复的比较研究、探索经济高效的采石场生态重建方法是未来的研究方向。     

Factors affecting the distribution patterns of zebra and wildebeest in a resource-stressed environment

Understanding the spatial dynamics of landscape use by free-ranging herbivores is integral for successful ecosystem management. We used binary logistic regression analyses to determine the relative importance of biotic, abiotic and human factors in influencing the distribution (presence/absence) of wild grazers on two Maasai ranches in Kenya's Amboseli-Tsavo ecosystem. Both ranches had low grass biomass and suffered from regular droughts. We found that grazers consistently located themselves where grass biomass was highest, usually irrespective of grass quality, suggesting that forage quantity may be the limiting factor where grass biomass is generally low. The availability of surface water had no significant effect on the likelihood of grazers being present, even in the dry season.     

Factors associated with Diaphorina citri immigration into commercial citrus orchards in São Paulo State,Brazil

Seasonality often influences multiple aspects of vector-borne plant diseases. With respect to the management of plant disease vectors, an understanding of the factors driving seasonal changes in vector flight activity may improve management outcomes by facilitating more proactive application of control measures. One of the most challenging issues for citrus Huanglongbing management is to forecast when disease primary spread by bacteriliferous Diaphorina citri will occur. We monitored the temporal patterns of immigrating psyllids, using upwards of 1,200 traps spread among 9 citrus farms and checked on a weekly basis over 4 years. This dataset was analysed with a set of hierarchical models to estimate the effect of climatic variables on citrus foliage production (i.e. flush), and effects of climatic variables and citrus foliage dynamics on D. citri catches over the season. The results showed substantial seasonal variability in immigrating D. citri abundance, with the critical dispersal/migration period occurring between end of winter and spring. During this period, 65% of the total psyllids were collected on sticky traps. Seasonality of immigrating D. citri coincided with changes in certain climate variables, with negative effects of humidity and daily maximum temperatures, and a positive effect of rainfall amount in prior weeks. Maximum temperature and both daily minimum temperature and rainfall during prior weeks were also associated with new citrus flush production, which itself was positively related to immigrating D. citri abundance. Based on these results, citrus growers should be aware and intensify the frequency of psyllid control tactics (i.e. insecticide and/or kaolin sprays) during this period in order to prevent Ca. L. asiaticus transmission. These results are an important step towards developing the predictive framework needed to refine D. citri and huanglongbing management.     

L-阿拉伯糖对尿酸的调节作用

转录因子是一类在生物生命活动过程中起到调控作用的重要因子,参与了各种信号转导和调控过程,可以直接或间接结合在顺式作用元件上,实现调控目标基因转录效率的抑制或增强,从而使植物在应对逆境胁迫下做出反应。 WRKY转录因子在大多数植物体内都有分布,是一类进化非常保守的转录因子家族,参与植物生长发育以及响应逆境胁迫的生理过程。众多研究表明,WRKY转录因子在植物中能够应答各种生物胁迫,如细菌、病毒和真菌等;多种非生物胁迫,包括高温、冷害、高光和高盐等;以及在各种植物激素,包括茉莉酸( JA)、水杨酸( SA)、脱落酸( ABA)和赤霉素( GA)等,在其信号传递途径中都起着重要作用。 WRKY转录因子家族蛋白至少含有一段60个氨基酸左右的高度保守序列,被称为WRKY结构域,其中WRKYGQK多肽序列是最为保守的,因此而得名。该转录因子的WRKY结构域能与目标基因启动子中的顺式作用元件W￣box( TTGAC序列)特异结合,从而调节目标基因的表达,其调控基因表达主要受病原菌、虫咬、机械损伤、外界胁迫压力和信号分子的诱导。该文介绍了植物WRKY转录因子在植物应对冷害、干旱、高盐等非生物胁迫与病菌、虫害等生物胁迫反应中的重要调控功能,并总结了WRKY转录因子在调控这些逆境胁迫反应过程中的主要生理机制。     

昆虫病原线虫与环境生物、非生物因素关系的研究进展

昆虫病原线虫(Entomopathogenic nematodes)是业已商业化的昆虫寄生性天敌,对农林和卫生等重要害虫具有安全和有效的控制作用.这类线虫与环境生物和非生物因素存在密切的联系.影响昆虫病原线虫的环境生物因素包括同类线虫、共生细菌、寄主昆虫、寄生真菌以及其它昆虫病原物等;影响昆虫病原线虫的环境非生物因素主...