Assessing adaptability of planted trees using leaf traits: A case study with Robinia pseudoacacia L. in the Loess Plateau, China

Leaf trait patterns and their variations with climate are interpreted as an adaptive adjustment to environment.This study assessed the adaptability of planted black locust (Robinia pseudoacacia L.) based on the analysis of leaf traits and the comparison of its leaf traits with inter-specific ones existing in the same area.We measured some water and N use related leaf traits: leaf dry mass per unit area (LMA) and N,P and K concentrations based on both leaf area (Narea,Parea and Karea) and leaf mass (Nmass,Pm...     

塔克拉玛干沙漠南缘头状沙拐枣幼苗生长和生物量分配对不同灌溉量的响应

水是荒漠生态系统中首要限制因子。由于水分限制程度不同,植物幼苗在生长过程中表现出不同的适应策略。在塔克拉玛干沙漠南缘的沙漠-绿洲过渡带,设计了0 mm（处理A）、100 mm（处理B）、200 mm（处理C）3种不同的灌溉量,对头状沙拐枣幼苗生长和生物量分配展开实验性研究。结果表明:①处理A比处理B和处理C地下生物量均有所增加;不同灌溉条件下,头状沙拐枣幼苗的根冠比均小于1,随灌溉量的减少头状沙拐枣幼苗的根冠比从0.19增加到0.32;即头状沙拐枣通过改变根系生物量分配适应水分条件变化。②随灌溉量的减少, 头状沙拐枣幼苗主根垂直深度和水平根幅均呈增加趋势。处理A时,头状沙拐枣幼苗根系深度达180 cm以上,处理B和C的根系深度均低于160 cm,表明头状沙拐枣幼苗通过根系的伸长生长来适应水分减少。③在生长过程中,头状沙拐枣通过老同化枝枯落适应土壤水分减少。④株高和冠幅随着灌溉量增加呈先增加后减小趋势,基径随着灌溉量的增加而增加,地上生长指标在不同处理间均无显著差异。     

柽柳属植物抗旱性能研究及其应用潜力评价

柽柳属植物普遍具抗旱性能,以沙生柽柳为最强。作者从生物生态学特性、水分生理状况及抗水分胁迫的生理机制3方面系统地探讨了柽柳属植物抗旱机制。柽柳叶、营养枝及根、茎的解剖结构均表明,柽柳已形成了一系列适应于干旱环境的旱性器官。柽柳抗旱性能越强,则水势越低,持水力越强。当缓慢水分胁迫时,柽柳体内有脯氨酸、可溶性糖、K⁺、Na⁺的主动积累,共同参与渗透调节。对柽柳抗旱性能的应用潜力进行了评价,指出柽柳是优良防风固沙树种,其柽柳包的"年轮"对揭示当时的生态环境及荒漠环境演变有一定的指示作用。仅分布于流沙地区的沙生柽柳可作为沙漠中的"水源标记"。柽柳具优良的抗逆基因,通过基因工程克隆柽柳抗逆基因并转移到作物和牧草中,必将在维护生态安全、改造生态环境的同时,获得显著的经济效益。     

On the habitability of the OGLE-2006-BLG-109L planetary system

We investigate the dynamics of putative Earth-mass planets in the habitable zone (HZ) of the extrasolar planetary system OGLE-2006-BLG-109L, a close analogue of the Solar system. Our work is inspired by the work of Malhotra & Minton. Using the linear Laplace–Lagrange theory, they identified a strong secular resonance that may excite large eccentricity of orbits in the HZ. However, due to uncertain or unconstrained orbital parameters, the subsystem of Jupiters may be found in a dynamically active region of the phase space spanned by low-order mean-motion resonances. To generalize this secular model, we construct a semi-analytical averaging method in terms of the restricted problem. The secular orbits of large planets are approximated by numerically averaged osculating elements. They are used to calculate the mean orbits of terrestrial planets by means of a high-order analytic secular theory developed in our previous works. We found regions in the parameter space of the problem in which stable, quasi-circular orbits in the HZ are permitted. The excitation of eccentricity in the HZ strongly depends on the apsidal angle of jovian orbits. For some combinations of that angle, eccentricities and semimajor axes consistent with the observations, a terrestrial planet may survive in low eccentric orbits. We also study the effect of post-Newtonian gravity correction on the innermost secular resonance.     

Three new species of Batrachospermum Roth (Batrachosper-maceae,Rhodophyta) in China

1 INTRODUCTION The first published records of genus Batra-chospermum Roth in China are from Jao (1941), when eleven taxa were reported. Since then, Shi, Hu and Kumano (1993), Shi (1994a, 1994b), Hua and Shi (1996), Xie et al. (1999, 2003), Xie and Shi (2003) have described in more detail the species from China. To date, 23 taxa of Batrachospermum Roth in China have been reported, of which, B. yunnanense, B. nothocladoideum and B. transito-rium are new species of this genus, and are…     

甜瓜种子萌发和幼苗生长对NaCl胁迫的响应

在盆栽条件下研究了NaCl胁迫对黄河蜜和白沙蜜甜瓜种子萌发和幼苗生长的影响。结果表明:NaCl胁迫对甜瓜种子吸水和累计发芽率影响较小,但明显延缓后期吸水和发芽进程。50 mmol·L-1以上NaCl浓度下,甜瓜种子相对发芽指数、相对活力指数和胚根生长量均下降。NaCl胁迫抑制甜瓜幼苗高度、株叶面积增长和干物质积累,抑制作用具有浓度和时间依赖性。NaCl胁迫对甜瓜幼苗形态生长的抑制作用强于对物质积累的抑制作用,对根系干物质积累的抑制作用高于对地上部干物质积累的抑制作用,对白沙蜜的抑制作用强于对黄河蜜的抑制作用。甜瓜种子和幼苗能适应的临界NaCl浓度在100~150 mmol·L-1之间,厚皮甜瓜可能更适合作为咸水灌溉和盐碱地生产的经济作物。     

益母草水苏碱对钉螺生理生化的影响

本实验研究了益母草水苏碱对钉螺糖原和总蛋白的生理生化影响:大于0.80g/L益母草水苏碱能够显著降低钉螺体内的糖原含量,减少幅度从11.68%到76.16%;益母草水苏碱也能够在一定程度上降低钉螺体内的蛋白质含量(从5.66%到13.69%),但减少量不及糖原显著;灭螺植物对钉螺的致死作用可能更多与钉螺组织细胞中的能量代谢有关。     

褐藻纲海带目Laminaria属和Saccharina属基于三个分子标记的系统发育分析

In the past two decades, many studies have focused on the classification within genus Laminaria, ultimately trying to divide it into two subgroups or genera: Laminaria and Saccharina. A significant debate still surrounds the question of its division, as the conflicting phylogenetic hypotheses that have resulted from the classification studies are based on different taxon sampling, molecular markers, or analysis methods. It is aimed at elucidate the molecular phylogeny within Laminaria and Saccharina. The nine species of Laminariales are sampled from northern Asia and Europe, and 23 new sequences in the nuclear, plastid, and mitochondrial genomes are determined to identify their taxonomic status. The phylogenetic analyses of 71 species are performed, including representatives from six of the seven families of the order Laminariales, based on three separate data sets. An evidence is provided to strongly support a clear split that maintains the two recognized genera, Laminaria and Saccharina, with Laminaria appearing to be the ancestor group. Further, analyses indicate that all taxa in Saccharina and Laminaria did not form a monophyletic lineage, instead Laminariaceae and Lessoniaceae grouped together interlacedly, and Costariaceae appeared as the sister taxon of the Lessoniaceae–Laminariaceae clade. In the phylogenetic analysis, mitochondrial c oxidase I(COI) sequences appeared to be the most credible molecular marker which was more befitting than nuclear encoded internal transcribed spacer(ITS) and plastid encoded rbcL for establishment of Laminariales systematics. It is the most comprehensive phylogeny of the order Laminariales, and contributes to an enhanced understanding and estimation of the phylogenetic relationships for the economically important seaweeds, Laminaria and Saccharina.