玉兰花粉个体发育及绒毡层动态

苏联植物学家A．L．塔赫他间在<有花植物（木兰植物）分类大纲>(Ta-khtaian，1980)中认为广义的木兰目是最原始的和最古老的类群，由它产生被子植物所有其它主要分枝。根据这个观点，作者试图以木兰科玉兰(Magnol iadenudata Desr.)，花粉个体发育为主题，探讨它们的原始性状、特点及其在系统发育上的地位。 下面就其花粉个体发育顺序，扼要概括如下： 1．小孢子母细胞、减数分裂到四分体时期：细胞器发生重组，质体和线粒体发生脱分化与再分他的循环。在此期间，细胞中还有大量胞质小泡，高尔基体小泡参与胼胝质壁物质的形成，其他小泡与脂体物质的沉积有关。晚二分体时期，原外壁物质开始沉积，胞质小泡可能涉及原外壁的形成和未来萌发孔的位置。 2．游离小孢子时期：细胞器变得丰富而活跃，特别是粗糙内质网大量出现，它们与脂体的形成和运输有关。此时，外壁外层已形成，外壁内层和内壁开始发育。 3．两细胞花粉时期;质体出现极性分布，生殖细胞中不含质体。生殖细胞随着位置的推移，其形状和壁的结构、性质也发生变化，生殖细胞由凸透镜形变成球形以至梭形。同时，生殖细胞壁最初含纤维素和胼胝质物质，以后壁物质逐渐消失，当生殖细胞变为梭形时，在生殖细胞壁的双层膜间又出现亲锇物质沉积。有趣的是，在生殖细胞星球形时，营养细胞中的脂体紧挨并围绕生殖细胞，形成一层明显的脂体冠。 玉兰成熟花粉为远极单槽，营养细胞中造粉体里园球形，内部充满大量均匀小淀粉颗粒，生殖细胞形状特殊，在有丝分裂前两极具明显的细胞质延伸和突起。从花粉个体发育着，玉兰花粉壁带有若干裸子植物性状和原始特征。最重要的特点表现在：①外壁内层具片层状结构;②I柱：状层虽具稀疏小柱，但在孢壁分沁过程中，”在小柱之问还有大小不同的孢粉素颗粒;③在萌发孔处，外壁外层往往扩张、外折，形似穗花杉和香榧的残余气囊。玉兰花粉的内壁特殊，由内壁-l、内壁-2和内壁-3等三层形状和质地不同的结构组成。值得注意的是百合科的麝香百合内壁也呈明显不同的三层结构。 玉兰绒毡层为多层细胞，属分泌型。绒毡层细胞中细胞器很丰富，减数分裂期问达到高峰。细胞核明显地被质体和线粒体所包围。粗糙内质网常与膳体连在一起。四分体时期，原乌氏体排出，孢粉素在其上沉积。推测原乌氏体和孢粉素前体物质的形成与粗糙内质网活动和膳体形成有关，乌氏体有单个存在，也有以聚乌氏体或复合乌氏体形式出现。周绒毡层膜在二分体时期即开始形成，最初呈间断的薄膜小片，以后连续发育成膜。周绒毡层膜位于靠药壁细胞的绒毡层细胞四周及中层绒毡层细胞外切向面，而靠药室腔的绒毡层细胞则未见此膜。 总之，玉兰的生殖细胞特殊，附带脂体冠;后期呈梭形，两极具明显的胞质延伸和突起，不含质体。孢壁结构具明显原始性状，在某种意义上，一方面类似裸子植物，另一方面又有百合科的特点。绒毡层结构也有一些值得深入探讨的问题。

四种园林植物的热值与养分特征

测定了蔷薇科植物美人梅、樱花和木兰科植物白玉兰、广玉兰不同组分的热值、养分和灰分含量,探讨4种植物不同发育阶段根系、枝干和叶等器官的热值分配特征及其影响因子.结果表明:4种植物不同组分干质量热值和去灰分热值在17.02~21.93 kJ.g-1和18.42~22.57 kJ.g-1之间;叶片和细根具有较高的干质量热值和去灰分热值,去灰分热值随着根系和茎干(枝)的发育呈减小趋势.美人梅和樱花的干质量热值和去灰分热值总体上高于白玉兰和广玉兰.细根干质量热值和去灰分热值与其养分和灰分含量呈极显著相关(P<0.01).随着根系的发育,干质量热值和去灰分热值与有机碳含量的相关性逐渐降低,不同器官干质量热值与全氮含量相关性最强.

Analysis of chemical constituents of essential oil in purple magnolia leaves by gas chromatography-mass spectrometry

The essential oil in purple magnolia leaves was extracted by steam distillation approaches. The oil obtained was dried with anhydrous magnesium sulfate. According to the analysis of gas chromatography/mass spectrometry, more than 40 peaks were separated and 32 compounds were identified. The identified constituents represent 95% of the peak area of the essential oil. The main compounds were germacrene-D, santolina triene, caryophyllene, 1,3,7-octatriene, 3,7-dimethyl, and camphene, etc.

Constituents of the Leaves of Magnolia ovata

Two new lignans, magnovatins A (1) and B (2), along with nine known compounds, were isolated from the leaves of Magnolia ovata. The known compounds were identified as acuminatin (3), licarin A (4), kadsurenin M, 4-O-demethylkadsurenin M, oleiferin A, oleiferin C, spathulenol, parthenolide, and 11,13-dehydrocompressanolide. In addition, compounds I and 2 yielded four new derivatives (1a, 1b, 2a, and 2b). The structures of the new compounds were established on the basis of spectrometric data evaluation. Free-radical scavenging and antimicrobial activities of the major compounds 1, 3, and 4 were investigated.

Antipyretic and anti-inflammatory properties of the ethanolic extract, dichloromethane fraction and costunolide from Magnolia ovata (Magnoliaceae)

Aim of the study: Magnolia ovata (A.St.-Hil.) Spreng (formerly Talauma ovata), known as ""pinha-do-brejo"" or ""baguacu"", is a large tree widely distributed in Brazil. Its trunk bark has been used in folk medicine against fever. However, no data have been published to support the antipyretic ethnopharmacological use. This study investigated the antipyretic and anti-inflammatory effects of the ethanolic extract (EEMO). dichloromethane fraction (DCM), and the isolated compound costunolide. Materials and methods: The antipyretic and anti-inflammatory activities were evaluated in experimental models of fever and inflammation in mice. Results: The oral administration of EEMO, DCM and costunolide inhibited carrageenan (Cg)-induced paw oedema (ID(50) 72.35 (38.64-135.46) mg/kg, 5.8 (2.41-14.04) mg/kg and 0.18 (0.12-0.27) mg/kg, respectively) and was effective in abolishing lipopolysaccharide (LPS)-induced fever (30 mg/kg, 4.5 mg/kg and 0.15 mg/kg, respectively). EEMO was also effective in reducing cell migration in the pleurisy model. Intraplantar injection of costunolide also reduced the paw oedema, myeloperoxidase and N-acetyl-glucosaminidase activity induced by Cg in mice. Conclusions: Collectively, these results show, for the first time, that extracts obtained from Magnolia ovata possess antipyretic and anti-inflammatory properties, and costunolide appears to be the compound responsible for these effects. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Protein expression upon desiccation and imbibition of Magnolia ovata A. St.-Hil seeds

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Effects of drying rate and storage time on Magnolia ovata Spreng. seed viability

Magnolia ovata seeds have been reported as desiccation sensitive. In order to test if the drying rate would affect the assessment of storage behaviour of these seeds, the effect of different drying rates and storage times on the viability was tested. Seeds were dried over activated silica gel (fast drying) or salt solutions for different periods (slow drying) and stored at -20°C. Partial drying transiently increased the final germination and the germination speed index, but further drying resulted in reduction of these parameters. Drying rate affected the final germination and vigour. Seeds that were slow-dried to 0.10 g H 2O ̇ g -1 dw retained high viability when compared with seeds desiccated to the same water content level by the fast drying method, although their vigour was reduced. Only slow-dried seeds could be stored at -20°C for 90 d without reduction of viability. These data suggested that the storage behaviour of seeds of M. ovata seeds should be classified as intermediate.

Essential Oil and other Constituents from Magnolia ovata Fruit

The volatile and non-volatile constituents of the unripe fruits of Magnolia ovata (A. St.-Hil.) Spreng. (Magnoliaceae) were studied. The essential oils were obtained by hydrodistillation of the fruit of two plant populations (A and B) and analyzed by GC/FID and GC/MS. The oil of sample A was rich in sesquiterpenes, mainly spathulenol (19.3%), while the oil of sample B showed a predominance of aliphatic compounds, mainly hexadecanoic acid (52.0%). Extracts of the dried fruit contained fourteen known compounds including nine lignoids (magnovatin A, magnovatin B, acuminatin, licarin A, oleiferin A, oleiferin C, kadsurenin M, 4-O-demethylkadsurenim M and 7-epi-virolin), two sesquiterpene lactones (parthenolide and michelenolide) and three alkaloids (lysicamine, lanuginosine and O-methylmoschatoline). Michelenolide, 7-epi-virolin and lisycamine are reported for the first time in the species, while the remaining compounds have already been reported in the leaves and/or trunk bark of Magnolia ovata. Acetylation of oleiferin A yielded a new compound, acetyl oleiferin A, whose NMR data and that of michelenolide are furnished.