水分对药用兰科植物白及生理和形态结构的影响

通过水分控制实验,研究不同土壤水分条件对白及(Bletilla striata(Thunb.ex A.Murray)Rchb.f.)光合作用、叶片解剖结构、生物量和多糖含量的影响。结果表明,低水分处理不仅使白及的最大光合速率、气孔导度、光反应中心Ⅱ活性及叶绿素含量等参数降低;也使叶肉层变薄、上表皮增厚、生物量和多糖含量下降。气孔导度降低是白及在低水分条件下光合能力下降的主要原因。低水分条件可引起白及光合碳同化能力下降,导致生物量和多糖积累减少,进而影响白及的产量和品质。     

同质园栽培下的湖南鱼腥草居群叶表型性状多样性分析

将采自湖南的20个鱼腥草(Houttuynia cordata Thunb.)居群栽培于同质园内,通过测定9个叶片表型性状和6个叶片相对性状,采用方差分析、变异系数、相关性分析、主成分分析以及聚类分析等方法,对鱼腥草居群叶片形态的变异特征进行研究。结果表明:(1)同质园栽培的20个鱼腥草居群叶片15个表型性状均存在显著差异,居群间差异大于居群内差异;(2)居群内叶性状的平均变异系数变化幅度为5.63%~9.08%,说明居群内多样性程度较低,其中株洲攸县居群(P16)变异系数最高(9.08%),怀化溆浦居群(P3)变异系数最小(5.63%);(3)15个叶性状的平均变异系数变化幅度为3.71%~10.28%,说明各性状的多样性程度也较低,其中叶面积变异系数最大(10.28%),叶宽与叶中部宽之比(W_2/W_4)的变异系数最小(3.71%);(4)相关性分析显示,叶面积与叶宽、叶中部宽、叶长、叶基至叶宽处的距离、叶柄长都呈现出显著正相关,与叶尖夹角呈显著负相关,而与叶基夹角关系不大;(5)叶片15个性状中前3个主成分的贡献率为83.66%,聚类分析可将20个居群划分为心形、小心形、狭心形和大心形4类,呈现出间断分布的地理格局;(6)同质园实验说明叶表型性状多样性主要是由遗传物质决定的,对其多样性分析能为优良种质资源的选育提供理论依据。     

蚕豆叶片细胞中IAA的胶体金免疫电镜定位

利用胶体金免疫电镜技术对蚕豆(Vicia faba L.)叶片细胞中的IAA定位进行了研究。幼嫩叶片的叶肉细胞中金颗粒主要分布在细胞核和叶绿体中,细胞质及细胞壁也有金颗粒标记。成熟叶片的叶肉细胞中金颗粒主要分布在叶绿体和细胞质,细胞壁也有少量金颗粒标记,液泡中没有发现金颗粒标记。成熟叶片小叶脉的韧皮细胞发现有大量的金颗粒标记,金颗粒主要标记在传递细胞的细胞壁中。小叶脉的维管束鞘细胞中也有很多的金颗粒标记,金颗粒主要分布在叶绿体、细胞质及细胞壁中。幼嫩叶片组织不进行IAA的固定或用正常兔IgG代替IAA抗体染色的对照,很难发现金颗粒标记。对IAA在组织及亚细胞中的定位及其生理意义进行了讨论。     

玉米素对盐渍下葡萄叶圆片H2O2清除系统的影响

研究了盐渍条件下河岸葡萄(Vitis vulpina L.)叶圆片细胞膜相对透性、光合色素和可溶蛋白含量、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(AsA-POD)和愈创木酚过氧化物酶(G-POD)活性的变化以及施加玉米素对这些酶的影响。结果表明,叶细胞膜相对透性随盐浓度增加而增强;盐渍引起叶片光合色素和可溶蛋白含量减少并使CAT、AsA-POD和G-POD活性明显下降。玉米素处理明显抑制盐渍效应,可能与其对CAT、AsA-POD和G-POD的刺激作用有关。     

介绍双子叶植物叶结构分类术语

本文系统地介绍了双子叶植物叶结构分类术语。这不仅有利于术语规范化,而且有利于国内外同行交流。     

CO2浓度倍增对10种禾本科植物叶片形态结构的影响

在CO_2正常浓度(350μL/L)和倍增(700μL/L)条件下,对小麦(Triticum aestivum L.)、半野生小麦(T.aestivum ssp.tibeticum)、大麦(Hordeum vulgare L.)、野大麦(H.brevisubulatum(Trin.)Link)、水稻(Oryza sativa L.)、野生稻(O.meyeriana subsp.granulata)、谷子(Setaria italica(L.)Beauv)、狗尾草(S.viridis (L.)Beauv)、高粱(Sorghum vulgare Pers.)和玉米(Zea mays L.)等10种禾本科植物幼苗期叶的形态结构进行比较研究。结果表明,在CO_2浓度倍增条件下,除野大麦和玉米外,其它几种禾本科植物的叶片厚度普遍增加;表皮细胞密度下降(野大麦和谷子的远轴面除外)。其中C_3种类的平均气孔密度和气孔指数下降,C_4种类则呈相反趋势。在CO_2浓度倍增条件下,栽培种类表皮细胞密度和维管束鞘细胞中的叶绿体数明显增加,野生种类则呈相反趋势。气孔密度与气孔指数基本呈正相关。     

中国亚热高大竹类植物毛竹竹笋克隆生长的密度调节（英文）

 对许多多年生克隆植物来说,大量的研究表明：当光是限制因子时,随着立地密度的不断增加,克隆分株的出生率逐渐减小、死亡率逐渐增加。本文观测了乔木状高大竹类植物毛竹竹笋的出生与存活过程,结果表明：竹笋的出生率,即每样方的出笋数,明显地随着成竹立竹度的增加而增加。更确切地说,竹笋的数量,不管是出笋数还是活笋数,都明显地随着带新叶(1龄叶)的成竹立竹度的增加而增加,而与带老叶(2龄叶)的成竹立竹度相关性不显著。并且竹笋的死亡率是非密度制约的。这可能是由于对毛竹来说,其立地总是比较开敞,而且,其竹笋的生长在很大程度上是不直接需光的。     

Genetic variation in stomatal and biochemical limitations to photosynthesis in the annual plant, Polygonum arenastrum

 Terrestrial plant photosynthesis may be limited both by stomatal behavior and leaf biochemical capacity. While inferences have been made about the importance of stomatal and biochemical limitations to photosynthesis in a variety of species in a range of environments, genetic variation in these limitations has never been documented in wild plant populations. Genetic variation provides the raw material for adaptive evolution in rates of carbon assimilation. We examined genetic variation in gas exchange physiology and in stomatal and biochemical traits in 16 genetic lines of the annual plant, Polygonum arenastrum. The photosynthesis against leaf internal CO₂ (A−ci) response curve was measured on three greenhouse-grown individuals per line. We measured the photosynthetic rate (A) and stomatal conductance (g), and calculated the internal CO₂ concentration (ci) at ambient CO₂ levels. In addition, the following stomatal and biochemical characteristics were obtained from the A−ci curve on each individual: the degree of stomatal limitation to photosynthesis (L_s), the maximum ribulose 1,5-biphosphate carboxylase-oxygenase (Rubisco) activity (Vc_max) and electron transport capacity (J_max). All physiological traits were genetically variable, with broad sense heritabilities ranging from 0.66 for L_s to 0.94 for J_max. Strong positive genetic correlations were found between Vc_max and J_max, and between g and biochemical capacity. Path analyses revealed strong causal influences of stomatal conductance and leaf biochemistry on A and ci. Path analysis also indicated that L_s confounds both stomatal and biochemical effects, and is an appropriate measure of stomatal influences on photosynthesis, only when biochemical variation is accounted for. In total, our results indicate that differences among lines in photosynthesis and ci result from simultaneous changes in biochemical and stomatal characteristics and are consistent with theoretical predictions that there should be co-limitation of photosynthesis by ribulose-1,5-biphosphate (RuBP) utilization and regeneration, and by stomatal conductance and leaf biochemistry. Gas exchange characteristics of genetic lines in the present study were generally consistent with measurements of the same lines in a previous field study. Our new results indicate that the mechanisms underlying variation in gas exchange include variation in both stomatal conductance and biochemical capacity. In addition, A, g, and ci in the present study tended also to be positively correlated with carbon isotope discrimination (Δ), and negatively correlated with time to flowering, life span, and leaf size based on earlier work. The pattern of correlation between physiology and life span among genetic lines of P. arenastrum parallels interspecific patterns of character correlations. We suggest that the range of trait constellations among lines in P. arenastrum represents a continuum between stress avoidance (rapid development, high gas exchange metabolism) and stress tolerance (slow development, low gas exchange metabolism), and that genetic variation in these character combinations may be maintained by environmental variation in stress levels in the species’ ruderal habitat. Received: 28 March 1996 / Accepted: 13 August 1996     

Identification of RAPD markers linked to a locus involved in quantitative resistance to TYLCV in tomato by bulked segregant analysis

 In tomato, Bulked Segregant Analysis was used to identify random amplified polymorphic DNA (RAPD) markers linked to a quantitative trait locus (QTL) involved in the resistance to the Tomato Yellow Leaf Curl Virus. F₄ lines were distributed into two pools, each consisting of the most resistant and of the most susceptible individuals, respectively. Both pools were screened using 600 random primers. Four RAPD markers were found to be linked to a QTL responsible for up to 27.7% of the resistance. These markers, localized in the same linkage group within a distance of 17.3 cM, were mapped to chromosome 6 on the tomato RFLP map. Received: 21 August 1996 / Accepted: 4 April 1997     

Laurel forests in Tenerife,Canary Islands

 Stand structure and leaf area distribution of a laurel forest in the Agua García mountains of Tenerife are described. The site is situated at 820 m a.s.l., faces NNE, and has a humid mediterranean climate. Summer droughts are mitigated by relatively high air humidity and clouds. The natural mixed hardwood forest is composed of six major tree species: Laurus azorica (Seub.) Franco, Persea indica (L.) Spreng, Myrica faya Ait., Erica arborea L. and two species of Ilex (I. platyphylla Webb & Berth. and I. canariensis Poivet.). The experimental stand had a density of 1693 trees ha^– 1, a basal area of 33.7 m²ha^– 1, and a cumulated volume of above-ground parts of trees of 231 m³ ha^– 1 with a corresponding dry mass of 204 ton ha^– 1. Diameters at breast height ranged from 6 to 46 cm. Mean concentration of plant dry mass per volume was 1.17 kg m^– 3. The vertical pattern of leaf area distribution in individual trees for all tree species was characterized by a Gaussian-like curve. Stand leaf area index was 7.8. These evergreen, broad-leaved (laurisilva or lucidophyllous) forests represent a relic forest that was widespread in the Mediterranean region some 20 million years ago. Our data illustrate some of the structural characteristics of this historically widespread forest type. Received: 2 December 1994 / Accepted: 6 November 1995