毛竹茎木质化过程的组织细胞学研究

应用光学显微镜和透射电子显微镜，并结合组织化学和细胞化学方法，研究了毛竹（Phyllostachys pubescens Mazel）茎各组织中细胞壁的木质化过程、木质素异质性、酚酸类成分的分布、木质素在细胞壁中的沉积方式以及过氧化物酶的组织、细胞化学定位等。 研究结果表明：毛竹茎的原生木质部导管在维管束发育早期就已木质化;后生木质部导管和纤维细胞在维管束分化完成后，自胞间层和细胞角隅处开始木质化;基本薄壁组织细胞木质化的发生较晚，通常在茎的节间完成伸长生长后才开始，但也有少数薄壁组织细胞始终保持非木质化的薄壁状态。根据可见光显微分光光度的分析结果，纤维细胞壁在木质化的早期，主要形成愈创木基木质素（guaiacyl lignin）, 随着木质化过程的发展，紫丁得基木质素（syringyl lignin）含量不断增加，最后成为纤维细胞壁木质素的主要组成成分。导管分子的木质素主要成分为愈创木基木质素，基本薄壁组织细胞壁为愈创木基与紫丁香基两种。 毛竹茎各组织在紫外光激发下自发荧光的荧光显微分光光度分析表明，氨水处理可以有效地识别阿魏酸的分布，如在竹笋各种幼嫩组织中均分布有阿魏酸;而用过氧化氢／冰醋酸混合液处理，则可以区分木素与结合于半纤维素中的阿魏酸和对－香豆酸，随着毛竹茎的生长和细胞壁木质化的增加，阿魏酸的含量下降。 通过对毛竹茎纤维细胞壁木质化过程中超微结构的观察表明，高尔基体、高尔基小泡、内质网、壁旁体细胞器在木质素前体的形成和运输等方面均起着重要作用，而周质微管在细胞壁木质化过程中的具体作用方式尚不明确。木质素在细胞壁中的沉积方式分别为：胞间层的木质素呈分散的颗粒状沉积方式，导管次生壁的木质素为片层状沉积方式，而在纤维细胞次生壁Sl层中，木质素为团块状的沉积方式。木质素沉积方式与纤维素微纤丝的排列有密切关系。 在毛竹茎各组织的细胞壁尚未木质化之前，过氧化物酶仅分布于细胞角隅处，随着细胞次生壁的增厚和木质化的增强，过氧化物酶可大量出现在次生壁中;在纤维细胞次生壁中，木质素含量较高的St各层，过氧化物酶活性也较强，而木质素含量较低的Sl各层，过氧化物酶活性则较弱。由此表明，过氧化物酶直接参与了细胞壁木质素的合成。另外，在茎的部分基本薄壁组织细胞和韧皮部等未木质化的细胞壁中，过氧化物酶也同样表现出较强的活性，这说明在茎的不同组织中分布的这种酶，可能是几种不同功能的同工酶形式。

Differences in the climatic adaptation of silver birch (Betula pendula) and downy birch (B. pubescens) in Finland based on male flowering phenology.

Male flowering was studied at the canopy level in 10 silver birch (Betula pendula Roth) stands from 8 localities and in 14 downy birch (B. pubescens Ehrh.) stands from 10 localities in Finland from 1963 to 1973. Distributions of cumulative pollen catches were compared to the normal Gaussian distribution. The basis for the timing of flowering was the 50 per cent point of the anthesis-fitted normal distribution. To eliminate effects of background pollen, only the central, normally distributed part of the cumulative distribution was used. Development up to the median point of the distribution was measured and tested in calendar days, in degree days (> 5 °C) and in period units. The count of each parameter began on and included March 19. Male flowering in silver birch occurred from late April to late June depending on latitude, and flowering in downy birch took place from early May to early July. The heat sums needed for male flowering varied in downy birch stands latitudinally but there was practically no latitudinal variation in heat sums needed for silver birch flowering. The amount of male flowering in stands of both birch species were found to have a large annual variation but without any clear periodicity. The between years pollen catch variation in stands of either birch species did not show any significant latitudinal correlation in contrast to Norway spruce stands. The period unit heat sum gave the most accurate forecast of the timing of flowering for 60 per cent of the silver birch stands and for 78.6 per cent of the for downy birch stands. Calendar days, however, gave the best forecast for silver birch in 25 per cent of the cases, while degree days gave the best forecast for downy birch in 21.4 per cent of the cases. Silver birch seems to have a local inclination for a more fixed flowering date compared to downy birch, which could mean a considerable photoperiodic influence on flowering time of silver birch. Silver birch and downy birch had different geographical correlations. Frequent hybridization of birch species occurs more often in northern Finland in than in more southern latitudes. The different timing in flowering caused increasing scatter in flowering times in the north, especially in the case of downy birch. The chance of simultaneous flowering of silver birch and downy birch so increased northwards due to a more variable climate and also higher altitudinal variations. Compared with conifers, the reproduction cycles of both birch species were found to be well protected from damage by frost.

The cost of quinine Cinchona pubescens control on Santa Cruz Island, Galapagos

We analyse the cost of controlling the invasive quinine tree Cinchona pubescens Vahl in the highlands of Santa Cruz Island, Galapagos. Control costs in ten 400 m2 plots formed the basis for estimating the cost of control over the whole island. In the plots, densities were 2100–24,000 stems/ha (stems >150 cm tall) and 55,000–138,000 stems/ha (all size classes combined). Control involved uprooting small plants, and applying of a mix of metsulfuron methyl and picloram to cut stumps or to machete cuts in the bark of larger trees. These methods are presently used by Galapagos National Park field crews to control quinine. Costs (in man hours, herbicide and US$) were related to stem density; the density of stems summed across four height classes was a better predictor of costs than density of any one size class. Regressions (on all size classes combined) formed the basis for predictive models of costs. Costs ranged from $14 to $2225 per ha depending on stem density. The amount of herbicide (active ingredient/ha) that must be applied to high density stands of quinine is higher than typical rates of application in an agricultural setting. The cost of treating all existing plants once across quinine’s known range on Santa Cruz Island (c. 11,000 ha) was estimated at c. US$1.65 million. CDF Contribution Number 1013.

Estimativa de crescimento de carvão-vermelho (Diptychandra aurantiaca), capitão (Terminalia argentea) e timbó (Magonia pubescens) no Pantanal, MS.

2009

Verdun, Porte Mazel [i.e. Porte Chaussée] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 59818

Variabilidad en las características morfológicas y estructurales en diversas accesiones de Crataegus pubescens (HBK) Steud. Rosaceae: maloideae y su probable mecanismo de adaptación a las diversas condiciones ambientales [por] José Luis Gutiérrez Lobatos.

Tesis (Doctor en Ciencias Biológicas) U.A.N.L.

The DNA puff 4C expresses a salivary secretion protein in Trichosia pubescens (Diptera; Sciaridae)

DNA puffs are genomic regions of polytene chromosomes that undergo developmentally controlled DNA amplification and transcription in salivary glands of sciarid flies. Here, we tested the hypothesis that DNA puff genes code for salivary proteins in Trichosia pubescens. To do that, we generated antibodies against saliva and immunoscreened a cDNA library made from salivary glands. We isolated clones corresponding to DNA puff regions, including clone D-50 that contained the entire coding sequence of the previously isolated C4B1 gene from puff 4C. Indeed, we showed that puff 4C is a DNA puff region detecting its local transcription and its extra rounds of DNA incorporation compared to neighboring regions. We further confirmed D-50 clone identity in Western blots reacted with the anti-saliva anitiserum. We detected a recombinant protein expressed by this clone that had the expected size for a full-length product of the gene. We end with a discussion of the relationship between DNA puff genes and their products.

The role of the parenchyma sheath and PCD during the development of oil cavities in Pterodon pubescens (Leguminosae-Papilionoideae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

OIL GLANDS IN PTERODON PUBESCENS BENTH. (LEGUMINOSAE-PAPILIONOIDEAE): DISTRIBUTION, STRUCTURE, and SECRETION MECHANISMS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Anatomia e ultra-estrutura do pulvino primário de Pterodon pubescens Benth. (Fabaceae - Faboideae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Anatomia comparada do pulvino, pecíolo e raque de Pterodon pubescens Benth. (Fabaceae - Faboideae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diterpene esters of aristolochic acids from Aristolochia pubescens

From the acetone and ethanol extracts of the tubercula of Aristolochia pubescens, two diterpene esters of aristolochic acids were isolated, together with 23 known compounds. The structures of the compounds were determined on the basis of spectroscopic analysis. (C) 2003 Elsevier Ltd. All rights reserved.

Insecticidal activity of chemical constituents from Aristolochia pubescens against Anticarsia gemmatalis larvae

Acetone and ethanol extracts of the tubercula and several compounds isolated from Aristolochia pubescens (Willd) were bioassayed on velvebean caterpillars, Anticarsia gemmatalis (Hubner), for evaluation of the insecticidal activities. of the extracts subjected to bioassay, the acetone extract showed the highest activity. (-)-Cubebin did not show activity against soybean caterpillars, whereas aristolochic acid and ent-kaur-15-en-17-ol increased the larval period. These compounds, and (+)-eudesmin and (+)-sesamin, reduced the viability of this period, giving rise to malformed adults. These extracts and compounds are therefore potential botanical insecticide agents for the control of velvetbean caterpillars in soybean crops. (C) 2003 Society of Chemical Industry.