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利用扫描电子显微镜对桫椤科2属6种叶表面角质膜纹饰、表皮毛、气孔器类型、气孔器大小等叶表皮微形态特征进行观察和比较，探讨其分类学意义，编制供试2属6种分类检索表。结果表明：2属6种叶表皮表面角质膜纹饰均为脊状，气孔器大小无显著差异，气孔器类型均为平列型。表皮毛共有4种（囊状毛、片状毛、须状毛、盾状鳞），种间表皮毛差异较大，其中白桫椤表皮毛最丰富。黑桫椤副卫细胞有泡状突起，白桫椤副卫细胞有皱褶，其余4种副卫细胞表面均光滑无纹饰。笔筒树气孔器周围有绒毛层覆盖。黑桫椤、笔筒树气孔器表面有晶体。本研究结果表明2属6种叶表皮微形态特征多样性较为丰富，这些特征可作为种间鉴别的参考依据。 相似文献
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为了研究向日葵锈菌的致病机制,本文采用电子显微镜技术对向日葵锈菌的侵入和扩展过程进行了研究,结果表明,向日葵锈菌夏孢子萌发产生1个芽管,遇到合适结构的气孔后,在气孔上方形成附着胞从气孔侵入,胞间菌丝与叶肉细胞壁接触后分化出吸器母细胞,吸器母细胞进入叶肉细胞内部形成吸器。胞间菌丝在吸器母细胞处分化出次生菌丝,在叶肉细胞间扩展,病菌菌丝多在寄主细胞间隙或沿寄主细胞壁延伸。在病原菌侵染早期,寄主细胞的超微结构变化并不明显;侵染中、后期,被侵染叶肉细胞发生质壁分离,叶绿体膨胀变形,细胞器解体,细胞崩解。 相似文献
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为了解谷子叶片表皮微形态学特征,利用扫描电镜对3个谷子品种叶片表皮微形态结构进行观察。结果表明:谷子叶片表皮主要由表皮细胞、气孔器、乳突和表皮毛等结构组成;下表皮表皮毛分布浓密,气孔大小、气孔密度、单位面积内气孔总面积均大于上表皮。豫谷1号、豫谷18和冀谷19下表皮气孔周长分别比上表皮长9.77%、20.51%和24.36%,单个气孔面积分别是上表皮的1.22、1.58和1.34倍,气孔密度分别比上表皮高4.79%、37.60%和4.56%,单位面积内气孔总面积分别是上表皮的1.31、2.23和1.52倍。品种间比较,豫谷18叶片上下表皮表皮毛分布最为密集,气孔密度最大(上表皮221.84个/mm2,下表皮305.25个/mm2),气孔较小(上下表皮单个气孔面积分别为262.49、414.13 m2),单位面积内气孔总面积最大(174162.13?滋m2/mm2)。由此可见,品种间叶片表皮微形态结构的差异性可为揭示品种高产及抗性机理提供形态学依据。 相似文献
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大麦小孢子再生植株气孔保卫细胞长度与倍性的相关性 总被引：2，自引：0，他引：2
为了建立一种快速鉴定大麦小孢子来源植株倍性的方法,对大麦品种"花30"不同倍性(种子来源二倍体,小孢子来源单倍体和单倍体加倍系)早期植株的不同叶位、不同叶片部位的气孔保卫细胞长度进行了测定,考察了不同取材部位气孔保卫细胞长度的差异,对种子来源二倍体、小孢子来源单倍体和单倍体加倍材料的气孔保卫细胞长度的分布进行了区分。结果表明,"花30"单倍体材料的气孔保卫细胞长度在不同叶位以及不同叶片部位差异较小,而单倍体加倍材料和种子来源二倍体材料受叶片部位影响较大,单倍体和二倍体材料间气孔保卫细胞的长度差异显著,而单倍体加倍材料和种子来源二倍体材料间气孔保卫细胞长度未观察到明显差异。单倍体和单倍体加倍材料气孔保卫细胞的长度值范围分别为26.9~37.7μm和36.7~62.1μm;利用37μm临界值可对大麦小孢子来源的DH群体中的单倍体进行快速区分。 相似文献
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湖南省三种野生鱼腥草气孔显微观察 总被引：4，自引：0，他引：4
用撕剥法撕取采自湖南省3个地区的野生鱼腥草叶片下表皮，制成临时玻片在显微镜下观察其气孔大小和密度，并对其进行方差分析。结果表明：（1）湖南省3个地区野生鱼腥草叶片平均气孔大小依次是浏阳地区〉怀化地区〉邵阳地区。3个地区鱼腥草叶片平均气孔密度最大的是邵阳地区为115．33个／mm^2，最小的是浏阳地区为77．33个／mm^2。方差分析结果表明，3个地区气孔大小（以气孔长轴、气孔器长轴和短轴3个指标表示）存在极显著差异，气孔密度在3个地区鱼腥草间也存在显著差异。（2）3个地区鱼腥草叶片气孔均属于不规则型，气孔器的形状主要以椭圆形为主，存在少量近似圆形和长圆形的气孔器。 相似文献
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3种不同抗蓟马水平的榕树叶片表面超微结构和蜡质成分及含量的比较 总被引：1，自引：0，他引：1
为判定叶片表面结构及蜡质是否会影响寄主植物的抗虫性,以3种不同抗蓟马水平的榕树叶片作试验材料,通过扫描电镜观察叶片表面的超微结构,利用气相色谱-质谱联用仪（GC-MS）检测叶片表面的蜡质成分及含量,比较差异性。结果表明：3种榕树叶片的表面蜡质、表皮细胞、气孔器等微形态结构明显不同,高感品种蜡质平滑,表皮细胞山脉状突起细微,气孔密度和长度均较小;低感品种蜡质略显粗糙,表皮细胞山脉状突起略显丰富,气孔长度最长;高抗品种蜡质最为粗糙,表皮细胞山脉状突起纵横交错,气孔密度最大。3种榕树叶片的表面蜡质总量存在极显著差异,高感品种和低感品种的蜡质总量相对较高;每个品种的蜡质提取液可鉴定出21种已知化学结构的化合物,各类化合物相对含量随品种抗性的不同会有所变化,醇类占比随品种抗性水平的提高而提高,烃类相反,酸类、酯类和酮类则互有高低;各主要组分的离子峰面积随品种抗蓟马水平的高低而呈现大小排序变化,含量的变化均可影响榕树品种的抗蓟马水平。 相似文献
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据长南信雄报告,提高碳三植物的生产力,重要的是提高光合能力及光合产物的运转速度。笔者认为,与气孔阻碍CO_2扩散有关的叶构造特性为气孔密度,保卫细胞长及细胞间隙等。这些构造特性与光合速车间的相关系数一般较低,大麦仅在气孔密度不同的同质基因品系或品种间,其气孔密度与光合速率为有意义的正 相似文献
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Edward C. Lulai 《American Journal of Potato Research》2002,79(4):241-248
The susceptibility of potato tubers to excoriation (idiom = skinning injury) during harvest is a widespread problem that results in costly disease, defects, and shrinkage. Little is known about the physiology associated with susceptibility of immature periderm and the development of full and final resistance to skinning injury (skin-set) upon periderm maturation. The objective of this research was to determine the roles of phellem (skin) tensile and phellogen shear-related fractures in skinning injury and in the development of resistance to tuber-skinning injury upon skin-set. The resistance to skinning injury was measured on potato tubers with immature and mature periderm using genetically diverse cultivars during two growing seasons. Separate force measurements (mNm) were obtained to determine the relative strength associated with the “total resistance to skining” and the “phellogen shear component” (total resistance to skinning = phellem tensile component plus phellogen shear component). The relative strength of the “phellem tensile component” was calculated by subtracting the force measurement for the phellogen shear component from the total resistance to skinning. The results indicate that the phellem tensile component plays a minor role in the total resistance to skinning in immature and mature periderm. The relative strength of the phellem tensile component appeared to be nearly constant for all time points for each cultivar and did not measurably increase as the periderm approached maturation; this indicates that the phellem/skin tensile component does not contribute to skin-set development. However, the force required for fracture of the phellogen shear component did increase upon periderm maturation. These results indicate that the increased strength of the phellogen shear component was the determinant for the development of full resistance to skinning injury, i.e., skin-set. This research uncovers and defines the role of this second component, the phellem tensile component, for incorporation into the recently conceived paradigm for tuber excoriation and skin-set. These findings are consistent with and complement recent microscopical research which showed that the phellogen layer of immature periderm was the single tangential plane of fracture upon skinning and that this layer of cells was no longer prone to fracture upon development of full resistance to tuberskinning injury. The results were similar for all cultivars tested and provide a definite direction for future research on the biochemical changes and processes associated with phellogen cell wall strengthening, which comprises the phellogen shear strength component. 相似文献
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Development ofHelminthosporium solani Dur. & Mont. on artificially inoculated, excised potato tuber periderm, incubated in darkness and high humidity at 20 to 24°C, was studied using light and scanning electron microscopy. Spore germination occurred within 16 hours, and appressoria were observed 2 days after inoculation. Penetration of periderm was evident 4 days after inoculation. Conidiophores with young conidia developed on the periderm surface within 7 days of inoculation. Well-developed conidia were visible often by 9 days after inoculation. Rudimentary stromata were observed beneath conidiophore groupings at later stages of development. In histological studies,H. solani hyphae were found in the phellem, phelloderm, and cortex of infected tuber sections. Basal cells of conidiophores or stromata were observed on the surface and in the outer tangential cork cell layers. Several layers of suberized and sometimes collapsed cortical cells were observed beneath disrupted and collapsed, infected periderm. Cavities sometimes formed between periderm and cortex, and callosities were observed on cell walls of some cortical cells beneath infected periderm. 相似文献
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Tubers located at lower depths in bins of stored potatoes suffer from pressure-bruising which often develops into an internal grayish or blackspot-like defect. However, little is known about key physiological and cellular changes that constitute pressure-bruising and resulting defects that degrade potato marketability and profits. We determined the changes in periderm water vapor permeability and some of the changes in cellular integrity that may occur in pressure-bruised areas compared to non-pressure-bruised areas of tubers after eight months of storage. Porometric measurements of pressure-bruised areas revealed elevated water vapor loss, which is conducive to blackspot formation, even though there were no apparent breaks in the periderm of pressure-bruised areas. Pressurebruised areas did not appear to readily wound-heal, because the elevated water vapor loss was shown to continue, without decline, when the tubers were porometrically measured again 4 days after removal from the pressure-bruising environment. Analysis of changes in cellular integrity of pressure-bruised regions showed that the tough, rigid cells of the suberized phellem could be damaged or completely flattened by this form of stress. A layer of what appeared to be crushed cells was often detected beneath the pressure-bruised, but partially intact, phellem. Autofluorescence of the crushed layer appeared to be derived from cell walls of collapsed phelloderm cells, starch granules of neighboring cells and material accumulated as a physiological response to the cellular damage incurred from pressure-bruising. These results help explain why the blackspot-like defect sometimes occurs at pressure-bruise sites. 相似文献
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We developed a technique to quantitate native periderm permeability during tuber growth and maturation by porometrically determining vapor conductances. We also describe a simple, inexpensive means of determining the corresponding weight per unit area of suberized phellem cells (skin) in native periderm during tuber growth and maturation as a means of assessing the developmental status of native periderm. The porometric technique is very sensitive and rapid. Porometrically derived vapor conductances of mature native periderms were measured without difficulty, and native periderms were found to release ~0.005 moles of water vapor/meter2 native periderm surface/sec. into a dry test atmosphere. Immature native periderm released up to 28 times more water vapor than mature periderm even though the phellem cells were histochemically determined to possess both major components of suberin. We demonstrated use of the porometric technique by determining maturational changes in periderm permeability of growing/immature tubers and mature tubers at harvest. The technique revealed that the native periderm of Russet Burbank tubers was more permeable and had the potential to lose more water vapor, until becoming permeably mature, than Norchip or Norland tubers harvested on the same dates. The dry weight of the skin (phellem tissue) of native periderm (mg/ cm2) for all three cultivars increased during tuber growth, but plateaued to a relatively constant level, or slightly declined, while plants were still alive during the latter period of tuber growth. During this period, periderm vameable conductances were undergoing substantial declines. Comparison of skin dry weights of immature tubers indicated that stem end regions of tubers were developmentally ahead of equatorial and bud end regions; this difference decreased as the tubers matured at harvest time and was less apparent with some cultivars. 相似文献
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Champasri T Rapley R Duangjinda M Suksri A 《Pakistan journal of biological sciences: PJBS》2008,11(4):525-531
The experiment was carried out during the 2003 to 2006 at the Department of Fisheries, Khon Kaen University, Khon Kaen, Thailand in collaboration with the Department of Biosciences, the University of Hertfordshire, College Land, Hatfield, Herts, UK. Molecular RAPD technique was used for the determinations of DNA patterns of the fish genus Puntius Hamilton 1822. The fish samples of 1,500 individual fish were collected from fifteen wetlands in Northeast Thailand and they were used for DNA extraction. Before the experiment was carried out the fish samples were morphologically identified and it was found that the collected fish consisted of 9 species i.e., Puntius altus, P. aurotaeniatus, P. binotatus, P. gonionotus, (e) P. leiacanthus, P. orphoides, P. partipentazona, P. schwanenfeldi and P. wetmorei. Genomic DNAs were extracted from 5 mg of muscle tissues (skeleton muscles) with the use of PUREGENE DNA Isolation Kit for Laboratory Use, Gentra Systems, USA. Eighty decamer primers from four kits were subjected to a preliminary test. It was found that only 10 decamer primers were most suited for this PCR amplification. The results showed that genetic distant values being established among and between pairs of the fishes of the 9 fish species ranged from 0.191 to 0.456 for a pair between Puntius gonionotus and Puntius altus and a pair between Puntius schwanenfeldi and Puntius leiacanthus, respectively. Similarity coefficient values within the 9 fish species ranged from 0.109 to 0.231. The results on a Dendrogram of clusters showed that there were 5 minor groups of the 9 fish species but the 9 species could not be split or shifted into other genera of the fish due to small differences found within the values of similarity coefficients. 相似文献
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生物入侵种喜旱莲子草的染色体核型特征 总被引：2，自引：1，他引：1
对外来人侵植物喜旱莲子草(Atlernanthera philoxeroides)的染色体核型进行了分析.结果表明,该入侵种的染色体数为2n=96,属六倍体物种,各染色体间形态差异不明显,均为中着丝粒或近中着丝粒染色体,最长与最短染色体相对长度比为2.10,全套染色体未见随体,核型公式为2n=96=60 m+36 sm,核型类型为进化程度较高的2B型.喜旱莲子草的多倍性特征及2B核型为其生物入侵性提供了重要的细胞学证据,文中同时提出不改变基因组DNA序列结构的表观遗传变异可能是喜旱莲子草成功入侵的重要机制. 相似文献
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为了解华重楼根际芽胞杆菌种群多样性信息，本研究采用稀释平板法分离福建省光泽县华重楼品种根际的芽胞杆菌，并对其进行16S rRNA序列分析。结果表明：从华重楼根际共分离到17个形态差异的芽胞杆菌菌株；16S rRNA序列分析表明，17个菌株鉴定为8个种，归属于4个属，芽胞杆菌属(Bacillus)、赖氨酸芽胞杆菌属(Lysinibacillus)、类芽孢杆菌属(Paenibacillus)和绿芽胞杆菌属(Viridibacillus)，其中芽胞杆菌属的种类和数量最多。经抑菌试验分析，芽孢杆菌属的特基拉芽孢杆菌FJAT-43012对尖孢镰刀菌具有抑制作用。本研究结果表明，华重楼根际芽胞杆菌种群多样性较为丰富。本研究对芽胞杆菌资源的开发和利用提供良好的实验材料和理论基础。 相似文献
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采用基于LC-MS/MS的代谢组学方法,对加工过程中的香草兰豆荚中代谢物的动态变化进行研究。通过聚类分析、样本相关性分析和正交偏最小二乘判别分析表明鲜豆荚（FVB）与杀青豆荚（BVB）,发汗豆荚（SVB）与干燥豆荚（DVB）的组间差异比较小,其余各组的组间差异比较大。差异倍数分析表明,和FVB相比,其他豆荚上调的代谢物主要是黄酮类物质,并且以糖苷类物质为主。而下调的代谢物以核苷酸及其衍生物为主。火山图显示SVB与CVB差异显著的代谢物是最多的,有256种。FVB与SVB的上调差异显著的代谢物是最多的,有102种。只有FVB与BVB的上调差异显著代谢物的数量高于下调差异显著代谢物。当和FVB相比时,各阶段差异显著代谢物变化如下：上调的黄酮类化合物在BVB、SVB、DVB、CVB均包含黄酮、黄酮醇、黄酮碳糖苷、黄烷酮,而下调的还包含黄酮-木脂素;上调的脂质及其衍生物在SVB、DVB、CVB中包含脂质-甘油磷脂、脂质-甘油酯、脂质-脂肪酸,而BVB只包含脂质-甘油磷脂;上调的氨基酸及其衍生物在SVB中最高,达到12种,DVB、CVB阶段呈下降趋势,分别为7种和3种,下调的氨基酸及其衍生物随着加工的进行逐渐增多,陈化阶段多达16种。 相似文献
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在大豆胞囊线虫(Heterodera glycines)自然衰退土壤中分离得到3株镰刀菌,F-9-禾谷镰孢菌(F.graminearum Schwabel),F-2、F-15-尖孢镰孢芬芳变种(F.oxysporum var.red0lens(Wollenw)Gordon).实验室条件下,研究了这3株镰刀菌发酵液原液对... 相似文献