烟草受精前后胚囊中钙调素的免疫细胞化学定位

应用辣根过氧化物酶标记抗体的光镜免疫细胞化学技术和胶体金标记抗体的电镜免疫细胞化学技术定位烟草（Ｎｉｃｏｔｉａｎａｔａｂａｃｕｍｖａｒ．ｍａｃｒｏｐｈｙｌａ）胚囊成员细胞中的钙调素,比较了不同类型细胞之间钙调素的分布特点,并探讨了受精前后钙调素在胚囊中分布的变化规律。     

中国分类学文献中Swietenia mahagoni之订正

通过调查,对Swietenia mahagoni的后选模式、S.macrophylla的主模式与中国分类学文献(如《植物分类学报》、《广州植物志》、《中国高等植物图鉴》、《云南植物志》、《广东植物志》、《中国植物志》和《中国高等植物》)的S.mahagoni作比较,证实中国分类学文献将S.mahagoni和S.macrophylla相混,上述分类学文献中的S.mahagon是S.macrophylla King。桃花心木(S.mahagoni(L.)Jacq.)的羽状复叶及小叶较短,小叶长度绝不超过10 cm,果卵球形,长度绝不超过15 cm;而大叶桃花心木(S.macrophylla King)的羽状复叶及小叶较长,总有一部分小叶的长度超过10 cm,果长卵球形,长12~22 cm。     

大叶秦艽的组织培养与植株再生

以秦艽的叶和下胚轴为外植体,成功地诱导出愈伤组织和再生植株.诱导愈伤组织最合适的培养基为附加2 m g·L- 1 2 ,4 - D和0 .5 mg·L- 1 6 - BA的MS培养基,诱导率可达到10 0 % .愈伤组织转移到附加2 mg·L- 12 ,4 - D和0 .5 mg·L- 1 KT和5 0 0 m g·L- 1 L H的MS培养基上进行继代培养,增殖后的愈伤组织转移到附加0 .1mg·L- 1 2 ,4 - D和0 .5 m g·L- 1 6 - BA的MS分化培养基上进行分化,其分化率可达到86 .6 7% ,将分化出的芽转接到不加激素的MS上,结果可生长出大量的分化苗.     

Imbibition of Swietenia macrophylla (Meliaceae) seeds: the role of stomata

BACKGROUND AND AIMS: The occurrence of stomata in seed coats is uncommon and there is limited information about their function(s). The aim of this study was to verify the distribution of stomata in seed coats of Swietenia macrophylla and to relate it to the imbibition process and aspects of the structure of the outer integument layers. METHODS: For the structural and ultrastructural studies, the seeds were processed using the usual techniques and studied under light and scanning electron microscopes. Histochemical tests were employed to identify the cell wall composition in the different seed coat portions. To assess the role of the stomata in the imbibition, non-impervious seeds were compared with partially impervious ones, in which only the embryo, median or hilar regions were left free. Further, the apoplastic pathway marker was employed to confirm the role of the stomata as sites of water passage during imbibition. KEY RESULTS: A positive relationship was observed between seed coat thickness and stomata density. The stomata were devoid of movement, with a large pore. They occurred in large numbers in the embryo region and extended with lower frequency towards the wing. Imbibition rates were related to stomata density, suggesting that the stomata act as preferential sites for water entry in the S. macrophylla seeds. CONCLUSIONS: At maturity, the stomata in the seed coat play a significant role in seed imbibition. The data may also infer that these permanently opened stomata have an important role in gas exchange during seed development, aiding embryo respiration.     

Morphogenic response in vitro of epicotyl segments of Citrus macrophylla

Abstract

The influence of explant orientation, contact of the cut surface with the medium, type of growth regulators and distance of epicotyl cuttings from the cotyledonary node (the part of the seedling where the cotyledons are attached) on in vitro morphogenesis of Citrus macrophylla (alemow) was evaluated. Maximum number of shoots was induced from epicotyl segments placed horizontally.     

Fluctuation of Vegetative Storage Proteins in the Seedlings of Swietenia macrophylla, Analogous to the Seasonal Changes of Those in the Shoot of the Adult Tree

In order to Identify appropriate plant materials for studying the gene expression and biological function of vegetative storage proteins （VSPs） in woody plants, the VSPs in the seedlings of Swietenla rnacrophylla King were investigated by using light microscopy, sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE） and Western.blotting. The seed of S. macrophylla was rich in storage proteins that accumulated In the vacuoles of cotyledon parenchyma cells in appearance of compact spherical grains. The growth and development of S. macrophylla seedlings were characterized by an obvious growth rhythm. The storage proteins In seeds disappeared during seedling growth while VSPs appeared in the stem 2 weeks after seedling leaves matured. Thereafter, the VSPs In the seedling stem almost exhausted during new shoot growth, and when the leaves of new shoot Just matured, both the stem beneath the new shoot of seedlings and the stem of new shoot started to accumulate VSPs. Nitrogen application dramatically Increased the level of VSPs, but had little influence on the dynamics of VSP consumption and accumulation in seedling stem. Together with these data, the fluctuation of VSPs in seedlings was very similar to that in the branches of the adult trees. In addition, seedlings are easy to be treated due to their small size. Our results suggested that S. rnacrophylla seedlings were suitable for Investigating the biological roles of VSPs and the mechanism of nitrogen storage in trees.     

Factors Limiting Post‐logging Seedling Regeneration by Big‐leaf Mahogany (Swietenia macrophylla) in Southeastern Amazonia,Brazil, and Implications for Sustainable Management1

Post‐logging seedling regeneration density by big‐leaf mahogany (Swietenia macrophylla), a nonpioneer light‐demanding timber species, is generally reported to be low to nonexistent. To investigate factors limiting seedling density following logging within the study region, we quantified seed production rates, germinability, dispersal patterns, and seed fates on the forest floor through germination and the first seedling growing season in southeastern Amazonia, Brazil. Fruit production rates were low by three logged and one unlogged populations compared to reports from other regions. Commercial‐sized trees (>60 cm diameter) were more fecund than noncommercial trees (30–60 cm diameter) at two sites, averaging 14.5 vs. 3.9 fruits/tree/year, respectively, at Marajoara, a logged site, over 8 yr. Fruit capsules contained an average of 60.3 seeds/fruit, 70 percent of which appeared viable by visual inspection. Sixty‐seven to 72 percent of apparently viable seeds germinated in nursery beds 2.5 mo after the dispersal period, when wet season rains began. Dry season winds blew most seeds west‐northwest of parent trees, with median dispersal distances of 28 and 9 m on west and east sides of parent trees, respectively. Nearly 100 percent of seeds fell within an area of 0.91 ha. On the forest floor beneath closed canopies, mammals, invertebrates, and fungal pathogens killed 40 percent of apparently viable seeds, while 36 percent germinated. Nine months after seedling establishment—midway through the first logging season following seed dispersal—14 percent of outplanted seeds survived as seedlings, representing 5.8 seeds/fruit. We conclude that seedlings are likely to survive in logging gaps at appreciable densities only in rare cases where previous year fruit production rates by logged trees were high (4–12.5% of commercial‐sized trees/year at Marajoara) and where tree crowns were felled in west or northwest directions.     

Relationship between specific leaf area,leaf thickness,leaf water content and <Emphasis Type="Italic">SPAD-502</Emphasis> readings in six Amazonian tree species

The aim of this work was to assess the effect of leaf thickness, leaf succulence (L_S), specific leaf area (SLA), specific leaf mass (W_s) and leaf water content (LWC) on chlorophyll (Chl) meter values in six Amazonian tree species (Carapa guianensis, Ceiba pentandra, Cynometra spruceana, Pithecolobium inaequale, Scleronema micranthum and Swietenia macrophylla). We also tested the accuracy of a general calibration equation to convert Minolta Chl meter (SPAD-502) readings into absolute Chl content. On average, SPAD values (x) increased with fresh leaf thickness (FLT [μm] = 153.9 + 0.98 x, r ² = 0.06**), dry leaf thickness (DLT [μm] = 49.50 + 1.28 x, r ² = 0.16**), specific leaf mass (W_s [g (DM) m⁻²] = 6.73 + 1.31 x, r ² = 0.43**), and leaf succulence (L_S [g(FM)] m⁻² = 94.2 + 1.58 x, r ² = 0.19**). However, a negative relationship was found between SPAD values and either specific leaf area [SLA (m² kg⁻¹) = 35.1 − 0.37 x, r ² = 0.38**] or the leaf water content (LWC [%]= 80.0 − 0.42 x, r ² = 0.58**). Leaf Chl contents predicted by the general calibration equation significantly differed (p<0.01) from those estimated by species-specific calibration equations. We conclude that to improve the accuracy of the SPAD-502 leaf thickness and LWC should be taken into account when calibration equations are to be obtained to convert SPAD values into absolute Chl content.     

中国筇竹属植物志资料

筇竹属是近年来新建立的一个属。本属原发表时仅有3种,标本採自四川、云南、贵州及湖北西部。以后又陆续发表了4种。作者在编写中国植物志筇竹属的过程中,对本属又做了初步整理,其中包括一新种及一新变型也在此一并发表。本文引证的标本均藏于本院标本室(代号SWFC)。