槐树试管正常苗与超度含水态苗茎叶的比较形态学研究

槐树(Sophora japonica L.)子叶经培养获得了大量的试管苗,依其形态正常与否可将其分为正常苗、超度含水态苗和介于二者之间的过度含水态苗。其自由水含量明显不同,正常苗低于50％,超度含水态苗高于79％,而过度含水态苗约为70％。以扫描电镜对其茎、叶的形态学结构进行了比较研究,结果表明:正常苗茎、叶表皮结构基本类似于实生苗,而过度及超度含水态苗的茎、叶表皮层结构变异较大。主要表现在其表面凹凸不平,表皮层外稀有或无蜡质存在,表皮细胞形状及排列不规则,叶片近、远轴两面气孔器密度、大小及开度均较正常苗显著增大;保卫细胞形态、结构异常。上述特征,均显示出槐树试管过度及超度含水态苗易失水干化,这可能是其在移栽过程中难以成活的主要原因之一。     

一品红试管苗移栽驯化期叶片的解剖结构变化

对一品红试管苗移栽驯化,同时研究了驯化过程中叶片结构的变化,结果表明,一品红在珍珠岩基质中成活率达98%,随着移栽时间的延长,表皮细胞增大,排列紧密;叶肉细胞间隙减小,栅栏组织细胞长度增加,主脉增厚,导管数目增加,保水,输水和抗逆能力增强。     

玻璃化与正常苹果试管苗的叶片和茎的显微结构比较

以苹果品种‘鲁加5号’试管苗为试材,其用石蜡切片和电镜扫描观察方法,比较玻璃化与正常试管苗叶片和茎的显微结构的结果表明：苹果玻璃化试管苗的叶片和茎的显微结构与正常试管苗有显著差异,前者的叶片厚度变大,表皮细胞密度极低;表皮细胞体积膨大,液泡化,栅栏组织厚度减小,海绵组织厚度增加;气孔器的长轴变化不明显,短轴变宽,气孔密度极高;茎的维管组织中有空洞和塌陷,导管管壁多皱褶,筛管中无淀粉粒积累。     

姜试管苗移栽过程中的蒸腾及光合性能变化

用TPS-1型光合测定仪测定了移栽驯化过程中姜试管苗的光合速率、蒸腾速率等生理指标变化,结果表明：姜试管苗在移栽过程中叶片表观量子产额、羧化效率、净光合速率逐渐增加,而蒸腾速率和气孔导度则呈下降趋势,这有利于试管苗适应外界环境和自养。     

安徽景天属（Sedum）植物叶表皮研究

利用光学显微镜和扫描电子显微镜观察安徽省１２种景天属（Ｓｅｄｕｍ）植物的叶表皮,统计并测量报气孔类型,气孔大小,气孔密度及气孔指数等,描述了表皮角质膜,蜡质纹饰及气孔外拱盖的有关特征。结果表明：景天属植物叶表皮气孔器为不等细胞型。气孔器类型,表皮细胞形状及垂周壁式样,角质膜,蜡质纹饰等,种间无差异或极小,而气孔大小,气孔器分布特征,气孔密度,表皮毛等种间差异较大,建议在种间区分上将差异大的特征作为     

岷江上游干旱河谷海拔梯度上四川黄栌叶片特征及其与环境因子的关系

研究了岷江上游干旱河谷海拔梯度上四川黄栌（Cotinus coggygria）叶片特征及变化特点,以及它们与环境变化的相互关系。测定指标有叶片形念结构（叶长、叶宽、叶面积和叶长／叶宽）,表皮特征（气孔器密度和面积、孔径、表皮细胞密度和面积）以及生态特征（生物量、比叶最、饱和含水量）。结果表明。随着海拔升高叶长,叶宽、叶面积、生物量、饱和含水量以及表皮细胞面积呈增大趋势;而表皮细胞密度呈减小趋势;气孔器面积和比叶重在海拔1950m以下,随着海拔上升而增加。1950m的区域明显减小,气孔器密度的变化趋势与之相反;孔径和叶长／叶宽无明显变化。多元统计分析显示,叶面积、饱和含水世和气孔器面积主要与温和度有关,三者随着海拔升高和温和度降低呈增大趋势;随着水热综合因子的增加,气孔器密度减小而孔径和比叶重增大;随着年降水量的增加生物量和气孔器面积基增大趋势,面表皮细胞密度减小;表皮细胞面积随着生物温度降低而增加。综合分析表明,岷江上游干旱河谷缺水和生长季节高温是影响叶片特征变化的主要因素。     

安徽黄精属(Polygonatum)植物叶表皮研究

利用光学显微镜及扫描电子显微镜观察了安徽省黄精属９种植物的叶表皮;统计并测量了气孔类型、气孔大小、气孔密度及气孔指数等;描述了表皮角质膜、蜡质纹饰、气孔的形状及气孔外拱盖等有关特征。结果表明：黄精属植物叶表皮气孔器类型属只有２个保卫细胞而无任何副卫细胞的单子叶植物气孔器类型。气孔的某些特征,如气孔器类型、气孔器分布特征、表皮细胞形状及垂周壁式样、角质层及蜡质纹饰等在种间差异不大,可作种间区别的次级特征用。     

盐生植物星星草叶表皮具有泌盐功能的蜡质层

利用扫描电镜和 X射线电子探针研究了星星草 (Puccinellia tenuiflora)的叶表皮及其与生境高盐的关系。结果表明 ,叶表皮由表皮细胞和气孔器组成 ,下表皮气孔器多于上表皮 ,且常下陷 ,表皮具表皮毛。表皮细胞外存在丰富的蜡质纹饰和蜡质颗粒 ,这些蜡质包含盐离子 ,具有泌盐的功能。这些特征表明星星草受外界生态因素的影响 ,而演化出具有泌盐功能的蜡质层来适应所生长的高盐生境     

青藏高原不同海拔高度下全缘叶绿绒蒿叶表皮特征研究

采用胶带粘取叶表皮法,利用光学显微镜观测不同海拔高度下全缘叶绿绒蒿叶片的表皮毛、气孔及表皮细胞结构特征,探讨全缘叶绿绒蒿叶表皮特征与海拔高度的关系。结果表明,随着海拔高度增加,全缘叶绿绒蒿叶片上、下表皮毛密度、气孔密度和表皮细胞密度逐渐增加;气孔器及表皮细胞的长度、宽度和面积逐渐减小;表皮细胞的形态随着海拔升高由无规则形向多边形变化,垂周壁由波状向弓形或平直变化。全缘叶绿绒蒿叶表皮结构在不同海拔高度下表现出的差异,可能是植物长期在高原生态环境下的综合反应,以结构上的变化来适应对高海拔地区的环境特点,为进一步研究高海拔地区植物的适应性提供一定依据。     

中国西南地区独活属植物叶表皮微形态特征及其系统学意义

利用光学显微镜和扫描电镜对中国西南地区独活属16种1变种植物(分隶于中国独活属的全部4个组)的叶表皮微形态进行了观察,测量并统计气孔器大小、密度和气孔指数,并用统计学方法对远轴面气孔器长轴进行显著差异性分析.结果显示:无规则型气孔器普遍存在于所有研究类群的叶远轴面及个别类群叶近轴面,气孔器的分布和密度具有种间特异性.表皮毛普遍存在于远轴面及大部分类群近轴面,长短和覆盖密度因种而异.近轴面表皮细胞为多边形或者不规则形,垂周壁平直、浅波状或波状;远轴面表皮细胞形态多不规则形,表皮细胞垂周壁浅波状或波状.在扫描电镜下,叶表皮气孔器外拱盖内缘为近平滑、浅波状或波状;角质膜条纹状,有的附有颗粒状、鳞片状蜡质等结构.气孔器外拱盖形态以及蜡质类型是稳定的鉴别特征.研究表明独活属植物叶表皮特征存在较大的种间差异,对独活属的系统分类及进化研究具有重要意义,文中对叶表皮特征在独活属植物分类处理中的应用及系统进化问题等进行了讨论,并建立了以叶表皮微形态特征为依据的分类检索表.     

Ultrastructure of <Emphasis Type="Italic">Eucalyptus grandis</Emphasis> × <Emphasis Type="Italic">E. urophylla</Emphasis> plants cultivated ex vitro in greenhouse and field conditions

The young and expanded leaf micromorphology and ultrastructure of Eucalyptus grandis 2 E. urophylla juvenile plants, cultivated in greenhouse and field conditions, were analyzed by scanning and transmission electron microscopy. In greenhouse leaves epicuticular wax needles covered the abaxial and adaxial surfaces. On the adaxial surface, the needles form an atypical arrangement in lines, mainly over the anticlinal wall of epidermis cells. After plant transfer to field conditions, the organization of epicuticular wax was altered forming amorphous layers on the adaxial leaf surface, in contrast to the abaxial surface, which maintained the wax needle cover. In both culture conditions the lamellar cuticle formed on the young leaves surface disappeared during leaf enlargement. The ex vitro environment induced the development of hypostomatic leaves. The dorsiventral organization of greenhouse leaves was replaced by an isobilateral arrangement in field conditions with concomitant aerial space reduction. Results suggest that those structural changes may be some of the strategies to avoid excessive plant transpiration during Eucalyptus hybrid plants' acclimatization.     

LEAF ANATOMY OF TISSUE-CULTURED LIQUIDAMBAR STYRACIFLUA (HAMAMELIDACEAE) DURING ACCLIMATIZATION

Structural changes accompanying the acclimation process were observed in leaves of sweetgum, Liquidambar styraciflua, using light and transmission electron microscopy (TEM). Comparisons were made of leaves obtained from tissue culture, plantlets acclimated after transfer from the in vitro environment to soil, and field grown trees. Leaves of cultured plantlets lacked a differentiated palisade parenchyma and had spongy parenchyma interspersed with large air spaces. Field grown leaves showed distinct palisade and spongy tissues and a high cell density. New leaves from acclimated plantlets showed an elongation of the upper mesophyll with fewer intercellular spaces than cultured plants. Cells from leaves from in vitro plantlets had large vacuoles, limited cytoplasmic content and flattened chloroplast with an irregularly arranged internal membrane system. Acclimated and field leaf cells had a greater cytoplasmic content than cultured leaves, with the former having more dominate vacuoles. Chloroplasts had evident grana. Acclimated and field leaves had a well developed cuticle unlike leaves from culture.     

西安市常见绿化植物叶片润湿性能及其影响因素

利用接触角测定仪测定了西安市21种常见绿化植物叶片表面的接触角,探讨了叶片表面特性如蜡质、绒毛、气孔对接触角的影响。结果表明,植物叶片正背面、物种间的接触角差异均显著,叶片正面和背面接触角大小在40°～140°。接触角大小与变异系数呈负相关,可能由于接触角小的润湿叶片在不同的生境和位置下,受到环境条件的影响较大而出现大的变异;接触角较大的非润湿性叶片,环境物质持留时间较短,对叶片形态和组成影响较小,因而出现小的变异。植物叶片表面的接触角随蜡质含量的升高而增大。表皮蜡质去除后大部分叶片接触角明显降低,尤其是疏水性较强的银杏(Ginkgo biloba)、月季(Ro-sa chinensis)和紫叶小檗(Berberis thunbergii)。女贞(Ligustrum lucidum)正背面、加杨(Popu-lus canadensis)背面等亲水型的叶片蜡质去除后接触角反而增大。叶片绒毛的多少及其形态、分布方式对接触角具有重要的影响,不同的作用方式表现出润湿和不润湿的特征,人为将其去除可以增加叶片的润湿性。背面气孔密度与气孔长度、保卫细胞长度呈负相关;接触角则与气孔密度呈负相关,与气孔长度呈正相关。     

大豆叶片结构对CO_2浓度升高的反应(英)

应用光学显微镜和扫描电镜研究了ＣＯ２ 浓度对大豆（Ｇｌｙｃｉｎｅ ｍ ａｘ）叶片形态和解剖特征的影响。结果表明,叶片外部形态没有显著变化,而叶片气孔密度随ＣＯ２ 浓度升高呈下降趋势。对照组叶片上下表面和处理组的上表面均无表面角质蜡层,而处理组的下表面覆盖有大量星状的表面角质蜡层,它们在气孔区和非气孔区的数量基本差不多。此外,还发现叶肉中增加了一层栅栏组织,从而使叶片明显增厚。结果证实,ＣＯ２ 浓度增加将促进细胞分裂和表面角质蜡层的产生     

Arbuscular mycorrhizal fungi influence water relations, gas exchange, abscisic acid and growth of micropropagated chile ancho pepper (Capsicum annuum) plantlets during acclimatization and post-acclimatization

Little is known about the role of arbuscular mycorrhiza fungi (AMF) on physiological changes of micropropagated plantlets during acclimatization and post-acclimatization. Using chile ancho pepper (Capsicum annuum L. cv. San Luis), measurements were made of water relations, gas exchange, abscisic acid (ABA), plantlet growth and AMF development. Plantlets had low photosynthetic rates (A) and poor initial growth during acclimatization. Relative water content (RWC) decreased during the first days after transfer from tissue culture containers to ex vitro conditions. Consequently, transpiration rates (E) and stomatal conductance (gs) declined, confirming that in vitro formed stomata were functional and able to respond ex vitro to partial desiccation--thus avoiding excessive leaf dehydration and plant death. Colonization by AMF occurred within 3 days after inoculation. Colonized plantlets had lower leaf ABA and higher RWC than noncolonized (NonAMF) plantlets during peak plant dehydration (6 days after plant transfer)--and a higher A and gs as early as days 5 and 7. During post-acclimatization [after day 8, when RWC increased and stabilized], A increased in all plantlets; however, more dramatic changes occurred with AMF plantlets. Within 48 days, 45% of the roots sampled of inoculated plantlets were colonized and had extensive arbuscule development. At this time, AMF plantlets also had greater E, A, leaf chlorophyll, leaf elemental N, P and K, leaf dry biomass and leaf area, fruit production and differences in carbon partitioning [lower root/shoot ratio and higher leaf area ratio] compared with NonAMF plantlets. Rapid AMF colonization enhanced physiological adjustments, which helped plantlets recover rapidly during acclimatization and obtain greater growth during post-acclimatization.     

Variations of cuticular wax in mulberry trees and their effects on gas exchange and post-harvest water loss

Though mulberry (Morus alba) tree shows great adaptations to various climate conditions, their leaf water status and photosynthesis are sensitive to climate changes. In the current study, seven widely planted mulberry cultivars in Chongqing, Southwest China, were selected to analyze leaf cuticular wax characteristics, gas exchange index, post-harvest leaf water status and their relationships, aiming to provide new theory in screening high resistant mulberry cultivars. Mulberry trees formed rounded cap-type idioblasts on the adaxial leaf surface. Film-like waxes and granule-type wax crystals covered leaf surfaces, varying in crystal density among cultivars. The stomatal aperture on the abaxial surface of cultivars with high wax amount was smaller than that of cultivars with low wax amount. The amount of total wax was negatively correlated with the net photosynthetic rate (P _N), transpiration rate (E) and stomatal conductance (g _s) and positively correlated with the moisture retention capacity. It suggested that both cuticular wax and stomatal factor might be involved in regulating water loss in mulberry leaves under field conditions. The variability in moisture retention capacity and cuticular wax characteristics might be important in evaluating and screening mulberry cultivars for increasing silk quality and silkworm productivity.     

Stomatal Morphology during Acclimatization of Tobacco Plantlets to ex vitro Conditions

Image analysis was used in studying stomatal morphology during acclimatization of tobacco plantlets to ex vitro conditions, 45 d after transfer leaf area was 15 times, and total number of stomata per leaf four times increased. During acclimatization stomatal density was decreased considerably on both leaf sides, and was compensated by an increase in stomatal sizes, e.g., in stomatal length and in stomatal area (both guard cells and pore). Elongation of stomata was increased indicating that the originally circular stomata of in vitro plantlets were changed into elliptical ones in ex vitro acclimatized plants. This revised version was published online in June 2006 with corrections to the Cover Date.     

Two sides of a leaf blade: <Emphasis Type="Italic">Blumeria graminis</Emphasis> needs chemical cues in cuticular waxes of <Emphasis Type="Italic">Lolium perenne</Emphasis> for germination and differentiation

Plant surface characteristics were repeatedly shown to play a pivotal role in plant–pathogen interactions. The abaxial leaf surface of perennial ryegrass (Lolium perenne) is extremely glossy and wettable compared to the glaucous and more hydrophobic adaxial surface. Earlier investigations have demonstrated that the abaxial leaf surface was rarely infected by powdery mildew (Blumeria graminis), even when the adaxial surface was densely colonized. This led to the assumption that components of the abaxial epicuticular leaf wax might contribute to the observed impairment of growth and development of B. graminis conidia on abaxial surfaces of L. perenne. To re-assess this hypothesis, we analyzed abundance and chemical composition of L. perenne ab- and adaxial epicuticular wax fractions. While the adaxial epicuticular waxes were dominated by primary alcohols and esters, the abaxial fraction was mainly composed of n-alkanes and aldehydes. However, the major germination and differentiation inducing compound, the C₂₆-aldehyde n-hexacosanal, was not present in the abaxial epicuticular waxes. Spiking of isolated abaxial epicuticular Lolium waxes with synthetically produced n-hexacosanal allowed reconstituting germination and differentiation rates of B. graminis in an in vitro germination assay using wax-coated glass slides. Hence, the absence of the C₂₆-aldehyde from the abaxial surface in combination with a distinctly reduced surface hydrophobicity appears to be primarily responsible for the failure of normal germling development of B. graminis on the abaxial leaf surfaces of L. perenne.     

What do microbes encounter at the plant surface? Chemical composition of pea leaf cuticular waxes

In the cuticular wax mixtures from leaves of pea (Pisum sativum) cv Avanta, cv Lincoln, and cv Maiperle, more than 70 individual compounds were identified. The adaxial wax was characterized by very high amounts of primary alcohols (71%), while the abaxial wax consisted mainly of alkanes (73%). An aqueous adhesive of gum arabic was employed to selectively sample the epicuticular wax layer on pea leaves and hence to analyze the composition of epicuticular crystals exposed at the outermost surface of leaves. The epicuticular layer was found to contain 74% and 83% of the total wax on adaxial and abaxial surfaces, respectively. The platelet-shaped crystals on the adaxial leaf surface consisted of a mixture dominated by hexacosanol, accompanied by substantial amounts of octacosanol and hentriacontane. In contrast, the ribbon-shaped wax crystals on the abaxial surface consisted mainly of hentriacontane (63%), with approximately 5% each of hexacosanol and octacosanol being present. Based on this detailed chemical analysis of the wax exposed at the leaf surface, their importance for early events in the interaction with host-specific pathogenic fungi can now be evaluated. On adaxial surfaces, approximately 80% of Erysiphe pisi spores germinated and 70% differentiated appressoria. In contrast, significantly lower germination efficiencies (57%) and appressoria formation rates (49%) were found for abaxial surfaces. In conclusion, the influence of the physical structure and the chemical composition of the host surface, and especially of epicuticular leaf waxes, on the prepenetration processes of biotrophic fungi is discussed.     

Structural Response of Soybean Leaf to Elevated CO２ Concentration

The effects of CO2 concentration on the morphological and anatomical characters of soybean (Glycine max) leaf were investigated by means of light microscopy and SEM. It was noticed that exomorphology did not show dramatic change, while stomatal density decreased with increasing CO2 concentration. Under SEM, no epicuticular wax was observed on both abaxial and adaxial sides of the control group as well as on adaxial side of the treatment group. However, leaf surface of abaxial side was noticed to be densely covered with microasterisk epicuticular wax when they were exposed to CO2-enriched environment. The epicuticular wax deposition was present in equal abundance on both stomatal and nonstomatal areas. Furthermore, leaf thickness increased significantly due largely to the origin of an extra layer of palisade in the treatment group. The results confirmed that CO2 enrichment might enhance cell division and induce greater quantity of epicuticular wax.