花烛离体培养叶色变异株系的相关性状

以花烛(Anthurium andraeanum)间接器官发生途径中再生出的一株花叶变异植株为原始材料, 进行增殖并对得到的3个叶色变异株系的叶色相关性状进行了初步研究。结果表明: 通过愈伤组织器官发生途径和腋芽增殖途径对这一花叶苗进行增殖, 均分离到3种变异株系, 即花叶苗、黄化苗和天鹅绒绿色叶片苗; 天鹅绒绿色苗叶片中的叶绿素含量比正常离体苗的含量低; 叶片解剖结构表明, 叶绿体在叶肉细胞中的分布与其叶片表现型相同, 天鹅绒绿色叶片与正常叶片在解剖结构上无明显差异。花烛原套只具有1层细胞, 无明显的L2层分生结构, 因此叶肉的薄壁细胞完全由向各个方向分裂的原体细胞发育而来, 这种组织结构导致花叶叶片中含有叶绿体的细胞和不含有叶绿体的薄壁细胞呈不规则分布。这种花叶株系可以作为育种材料或直接作为盆栽花烛进行推广。     

花烛叶色嵌合体不同生长阶段叶色性状的保持特征

对20个花烛叶色嵌合体株系在不同生长阶段的叶色性状保持特征进行观察,并通过计算机程序辅助分析发现:离体培养阶段,植株嵌合叶片总数占总叶片数的比率及平均单株非绿色部分占总叶面积的比率均为最高,分别为81%和50.1%,两项数值分别高于温室生长阶段新生嵌合叶数占新生叶片总数的比率(46.2%)及新生叶片非绿色部分占新生叶片总面积的比率(23.0%);移栽后,叶片非绿色部分比率超过50%的9个株系中有7个不能正常生长而死亡,所剩13个株系的新生叶片嵌合叶数减少,非绿色部分面积比率缩小,叶片趋向转为绿色;施用营养液后,5个株系的新叶非绿色部分面积比率回升。这些现象表明:营养条件充分有利于嵌合株系花叶性状的保持;嵌合株系中非绿色部分面积大于50%的株系生活力弱,不宜过早移栽;在茎尖分生组织形成叶原基的过程中,可能存在正常细胞与突变细胞的竞争,其结果是一方取代另一方或二者达到动态平衡。     

槐树组织培养中再生植株的比较解剖学研究

本文对组织培养过程中,槐树(Sophora japonica L.)再生植株正常苗和玻璃苗的叶、茎及茎端的解剖结构进行了比较研究。结果表明:正常苗结构基本类似于实生苗,玻璃苗结构变异较大;玻璃苗叶片变厚,表皮细胞形状不规则,气孔保卫细胞萎缩变形,叶肉无明显的栅栏组织与海绵组织分化,叶绿体含量较少,叶维管组织发育不良;茎横切面形状不规则,表皮上气孔数目较多,皮层厚角组织不明显,维营束大致分布成一轮,形成不规则维管柱;茎端分生组织细胞层数较少,不呈现典型的原套原体结构。     

离体条件下沙枣的形态解剖学观察

在离体培养条件下,沙枣(Eiaeagnus angustifolia L.)苗分正常苗和异常苗两种类型。正常苗的株型、叶的形状和颜色与自然条件下的实生苗完全相同,所不同的是试管正常苗的叶肉中无栅栏组织,整个叶肉组织全被具叶绿体的同形薄壁细胞所充塞,无典型的表皮细胞和主脉不发达。显然在离体培养条件下,沙枣已丧失其旱性结构特征,异常苗变化更大。株型呈莲座状,园棒状等多种形态。其解剖学结构基本上不保持模式叶的形态特征。叶肉不分化,细胞不含叶绿体。茎的解剖学结构也有类似现象,主要表现在输导组织发育不良。     

香蕉束顶病和花叶心腐病的快速测定技术研究

种植无病蕉苗是防治香蕉束顶病和花叶心腐病的根本措施。筛选无病蕉苗的快速测定技术。除可引用2,3,5-氯化三苯基四(氨)唑浸渍徒手切片;在36℃条件下。24小时后:束顶病株叶脉切片的维管束呈现红色,其它组织为红褐色;花叶心腐病株叶脉切片(含维管束)全部呈现黑褐色;而健株叶脉切片由原绿色变成红色,最后褪成无色。此外。也可取叶片主脉的徒手切片,用1％曙红B水溶液染色。健株切片呈桔红色,病株切片呈砖红色,通过镜检:束顶病株叶片切片的表皮下,可观察到围绕在维管束周围成堆的分布有畸形叶绿体细胞团;花叶心腐病的畸形叶绿体细胞团,多分布在薄壁细胞中,且多散生;而健株的切片没有发现这种畸形的叶绿体细胞团,两种方法同样可靠。     

榉树叶片解剖构造和叶肉细胞超微结构的观察

对取自不同季节的榉树(Zelkova schneideriana hand.-Mazz.)叶的解剖构造和叶肉细胞超微结构进行了观察。榉树叶表面被密集锥状单细胞毛,幼叶则还有头状腺毛。气孔多分布在叶下表面,为不规则型。上表皮细胞外壁具有明显的角质层加厚,局部上表皮由2层细胞组成。叶肉细胞分化为栅栏组织和海绵组织;栅栏组织1—2层细胞;海绵组织发达,常与气孔相连。叶肉有含晶细胞存在。叶脉的维管束鞘明显,是厚壁细胞。成熟叶肉细胞细胞器丰富,有8-9个周壁叶绿体,为巨大的长椭圆形,基粒片层清晰,有淀粉粒,少量脂滴。叶片开始转变颜色时,叶绿体由长椭圆形变得趋于圆形;基粒片层逐渐变得杂乱至模糊不清;脂滴数目增多。秋季叶色不同的榉树叶片解剖构造存在一定差异。     

小麦低温种质的器官结构特征

通过对小麦冠层温度的长期观测,发现自然界存在株温持续偏低的低温种质,与其相对应,也有株温持续偏高的高温种质存在。应用光学显微镜和电子显微镜研究了小麦低温种质叶片显微和超微结构,测量统计了叶肉细胞长度、单位面积叶肉细胞数目、单个叶肉细胞中的叶绿体数目、叶肉细胞层数和叶绿体基粒片层数。结果表明,低温小麦种质较高温种质叶肉细胞小,排列紧密,叶肉细胞层数较多;叶绿体数量多,叶绿体基粒片层丰富;叶片维管束密集;随着生育期向成熟趋近,叶肉细胞、叶绿体、籽粒腹沟区有色层细胞等结构衰老缓慢。     

冠层部位对金叶女贞叶片结构的影响

金叶女贞是一种在园林绿化上广泛应用的彩叶植物,上层叶金黄色,下层叶深绿色。本文利用常规植物制片技术,研究了叶绿素缺少的金叶女贞上层金叶和下层绿叶的解剖结构。结果表明:(1)金叶女贞上层金叶和下层绿叶的上表皮无显著差异,但是下层绿叶的下表皮细胞较小,气孔密度较低;(2)下层绿叶的叶肉组织较薄,细胞较大,排列疏松;(3)在下层绿叶中叶绿体类囊体片层排列密集,叶肉组织内单位体积叶绿体数量较少;(4)冠层部位对光合色素的积累有明显影响。叶绿素缺少的金叶女贞叶片结构显著受到冠层部位的影响,光合色素的变化幅度较一般植物更大,不同冠层部位叶片叶色有明显差异,可以作为研究植物冠层部位对叶形态、结构和生理生化影响的好材料。     

大麦和玉米叶片叶绿体中Rubisco及其活化酶的免疫金标记定位

运用免疫金标记电镜技术研究了禾本科C3植物大麦(Hordeum vulgare L.)和C4植物玉米(Zea mays L.)叶片中Rubisoo及其活化酶(RCA)的细胞定位,结果表明:两种植物叶片解剖结构及叶绿体超微结构差别明显.在大麦叶细胞中,只有一种叶肉细胞叶绿体,Rubisoo和RCA主要分布于叶绿体的间质中.在玉米叶细胞中,存在着维管束鞘细胞和叶肉细胞两种类型叶绿体,Rubisco主要分布于鞘细胞叶绿体的基质中,但在叶肉细胞叶绿体中亦有少量特异性标记;RCA在鞘细胞叶绿体和叶肉细胞叶绿体的基质中都有分布.两种植物叶绿体结构及光合作用关键酶定位的不同,体现了C3植物和C4植物在光合器结构与功能上的差异.     

建兰水晶艺叶片的超微结构和转录组学分析

水晶艺建兰(Cymbidium ensifolium)因其叶片上呈现出白色透明状,犹如水晶而得名,观赏价值高,但是其形成机理不明确。该研究以建兰‘铁骨水晶’为试验材料,通过对水晶叶片和绿色叶片进行显微结构和超微结构观察,并结合转录组测序等方法,探索建兰水晶艺叶片形成的原因。结果表明:(1)建兰‘铁骨水晶’水晶叶片比绿色叶片薄,叶肉细胞数量减少,形状不规则,且叶绿体含量少;水晶叶片的表皮气孔数量较绿色叶片显著减少;水晶叶片的叶肉细胞中叶绿体结构发育不良,叶绿体双膜和类囊体膜模糊,细胞中存在着大量的嗜锇颗粒。(2)转录组数据分析显示,水晶叶片中与光合作用-天线蛋白、光合作用等代谢途径相关的基因表达量显著下降,而与色素合成代谢途径相关的基因表达量上升。研究推测,建兰水晶艺叶形成的原因可能是由于与光合作用相关的基因表达量降低,导致叶绿体发育不良,叶绿素合成受阻,从而形成白色透明状叶片。     

古林箐秋海棠叶斑结构对叶色的影响

该研究以古林箐秋海棠(Begonia gulinqingensis)为材料,通过分析叶片形态特征、上表皮光学特性、组织结构、叶绿素含量及叶绿素荧光参数(F_v/F_m),探讨了叶片色斑的形成原因。结果表明:(1)古林箐秋海棠叶斑发生频率和数量无明显规律,但发生部位相对稳定,叶斑主要发生在正对叶柄的两条主脉之间。(2)斑区有两种光反射模式,点状反射和多角形反射,栅栏组织细胞呈近等轴的圆形,排列疏松,与上表皮细胞间存在空隙;非斑区只有点状反射模式,栅栏组织细胞为漏斗型,排列紧密,与上表皮细胞间不存在空隙。(3)斑区和非斑区叶绿体均有密集的堆积基粒和丰富的类囊体膜,斑区叶绿素a、b及总叶绿素含量仅比非斑区分别低24.9%、25.2%、25.1%。(4)叶绿素荧光参数(F_v/F_m)值斑区为0.793,非斑区为0.790。虽然斑区叶绿素含量比非斑区略低,但叶绿体结构完整,且叶绿素荧光参数与非斑区无显著差异。斑区上表皮与栅栏组织细胞间的空隙可使光线到达绿色组织时发生二次反射,在叶片表皮细胞边缘形成白色多边形光反射使该区域相对周围正常叶片区域偏白,基于上述结果可推测古林箐秋海棠的淡绿色块斑形成与特殊的叶片结构有关。     

Regeneration of chlorophyll chimeras from leaf explants ofNicotiana tabacum L.

Chimeral plants with variegated leaf blades were obtained by induction of organogenesis in primocultures of leaf explants ofNicotiana tabacum L. cv. Burley 49, chlorophyll mutation White Seedling. Only green plants regenerated from primocultures of explants taken from dark green leaf areas of the chimeras. The possibility of a multicellular initiation of chimera regeneration from tissue cultures is discussed.     

The frequency of marker changes in sugarcane plants regenerated from callus culture

Leaf tissue from five sugarcane clones with distinctive markers was cultured on a medium favoring callus growth. Transferred to a differentiation medium, calli produced over 5000 plants. Plants differentiated from two clones with stem markers exhibited a high rate of remission of the marker, but the marker reappeared in the vegetative progeny of these plants, and remission was, therefore, transient. Plants differentiated from callus from two clones with leaf markers showed a low rate of remission (2 or 3 per thousand) of the marker and the vegetative progeny was stable. A clone with variegated leaves produced plants with the majority having green leaves, some were albino, and some variegated, suggesting that plant differentiation may start with more than one cell. Permanent phenotypic change may result from tissue culture, but the results suggest that such changes are not frequent and may be confounded by temporary alterations or by chimeras formed in the process of differentiation.     

CALLUS FORMATION AND ORGANOGENESIS FROM CULTURED LEAF SEGMENTS OF CRASSULA ARGENTEA: CYTOKININ-INDUCED DEVELOPMENTAL PATTERN CHANGES

Culturing leaf segments on agar medium with a final concentration of 10^–4m isopentenyl adenine inhibits regeneration of plantlets, but stimulates some segments to produce regions of dense callus. The callus is initiated from the basipetal end of a cut vascular bundle, and is therefore the positional equivalent of root initiation during normal regeneration. Once callus has emerged, it forms a sphere of tissue attached to the leaf segment. The cells on the surface of the sphere are smaller than the cells toward the center. Some of these larger cells contain tannins or large starch grains. Shoots are sometimes initiated from organized meristematic regions of surface cells. Roots form endogenously from callus after shoot formation. This regeneration sequence, initially induced by cytokinin treatment, is strikingly dissimilar to the normal pattern, and provides an excellent example of a hormone-induced alteration to a developmental pattern.     

Callus Induction and Organ Differentiation in the Tissue Culture of Begonia fimbristipula Hance

This paper reports the organ differentiation in the tissue culture of Begonia fimbristipula Hance. Three types of regenerated plantlets were obtained: (1) callus differentiation, (2) growth center induced from the aseptic seedling leaf and (3) shoots were differentiated from roots developed from the callus. Callus could be obtained on SH medium as well as on MS basic medium supplemented with 2,4-D (0.1 ppm) +NAA (2.5 ppm) +KT (0.25 ppm). Experiments were carried out to compare the effects of different concentrations of sucrose on callus induction. It was found that the differentiation rate of callus was higher on MS medium than on SH medium. Comparative experiments were also carried out to find out the efficiency of callus differentiation by BA and 2ip at various concentrations. The better differentiation of callus was obtained at the range 0.25—2 ppm of BA, The cytological investigations showed that individual plantlet grown on the leaf was originated from the epidermal cells. According to our study, numerous plantlets can be obtained from a single leaf of aseptic seedlings. It is possible that this technique provides a way of rapid donal propogation of Begonia fimbristipula Hance.     

Fine Structure of Healthy and TMV-Infected Tobacco Cells Grown in Tissue Culture

Three types of tobacco (Nicotiana tabacum cv. Havana 38) callus: 1) healthy stem callus, 2) TMV-infected stem callus, 3) TMV-infected leaf callus; and leaves differentiated from healthy stem callus, and from TMV-infected leaf callus were compared for fine structure. In addition, the fine structure was observed of plastids in cells of leaves differentiated from callus isolated from stem sections of TMV-infected hybrid tobacco plants (N. tabacum cv. Havana 38 ×N. glutinosa) grown under high temperature. The cytoplasmic organelles in tissue cultured cells were similar to those in cells of greenhouse-grown tobacco plants. Except for plastids, TMV infection did not noticeably affect morphologically other cellular organelles in tissue culture cells. In TMV-infected leaf callus, numerous small bodies were seen in plastid-like bodies, while vesicle-like structures were observed in the stroma of plastids in leaves differentiated from callus of hybrid tobacco inoculated with TMV. Morphological variations of mitochondria, such as swelling and vacuolization of the inner matrix, occurred frequently in TMV-infected leaf callus. Needle-like crystalline inclusions or looped inclusions composed of many fine, long filaments were considered TMV particles orientated parallel to each other. The TMV particles were detected in the cytoplasm of tissue culture cells.     

Electron microscope studies on the morphogenesis of plastids

Comparisons of the ultrastructure of plastids in three kinds of variegated leaves of tomato plants were made. No difference in the structure and development of chloroplasts in normal green leaves and in the green tissue of variegated leaves was found. The albescent tissues of chromosomal genetic variegated leaves contained only aberrant plastids, which were amoeboid or cup-shaped and had large vacuoles in the stroma. Ribosomes were absent from all plastids in this kind of variegated leaves. Three types of plastids, i.e. chloroplasts containing grana, chloroplasts lacking grana, and plastids lacking internal membranes, were present in the pale green tissues of the variegated leaves of extrachromosomal genetic tomato mutants. Depending on the distribution of these plastids, five cell types were observed in these tissues. Ribosomes were present in all plastids in this type of variegated leaves. In the albescent tissues of variegated leaves induced by streptomycin treatment, two kinds of plastids were observed, one containing giant grana and the other lacking organized internal membranes. A common feature of plastids in this albescent tissue was the presence of light stainable ribosomes. It was suggested that the development of variegated leaves may be caused by blocking an early stage of plastid development. This work was carried out in the Department of Botany, University of California, Davis, by Grant-GB-11906 from National Science Foundation of U.S.A.     

Plantlet Regeneration from Callus and Parent Tissue 2Ornithogalum thyrsoides

Pieces of stem, leaf, ovary, sepals, and bulb scale of Ornithogalumall gave rise to adventitious plantlets when placed on basicMurashige and Skoog medium containing no added growth hormones.When one of the auxins, indole-3-acetic acid (IAA), -naphthaleneaceticacid (NAA), or 2, 4-diehlorophenoxyacetic acid (2, 4-D) wereadded to the medium, stem and leaf gave rise to callus fromwhich plantlets could be recovered by transfer to low auxinmedium or basic medium. Plants derived from parent tissue were diploid (2n = 12). Plantsderived from NAA callus were at first diploid but during seven5-week passages on NAA medium an increasing proportion of tetraploidplants, up to 50 per cent or more, were produced while the numberof plantlets recovered from the same amount of callus declined.     

Callus Induction and Organ Formation from Young Leaf of Wheat Triticum aestivum

Callus was obtained on modified PRL-4 medium supplemented with 2, 4-D from the segments of the first leaf of wheat seedling which had been germinated for 4 days. Roots and shoots were initiated and complated plantlets thus regenerated. The frequency of callus formation and its growth rate depended upon the concentration of 2, 4-D and the locations of segments on the leaf. When the concentration was 4 ppm or less, the callus could be produced only within the region from the leaf base to about 1cra apart. Both KT and 6-BA were inhibitory to callus formation. Histological examination showed that callus originated from the cells located at the place of vascular bundle sheath. The roots were frequently induced from leaf callus. During the process of callus induction, after 10–14 days incubation, the roots began to appear in the medium containing 2, 4-D of 2 ppm or less. The lower the concentration, the nearer to the base of the leaf the root-forming place was. In contrast, the higher concentration induced rooting at the higher part of the leaf but inhibited at the lower place. After 3 weeks incubation, the highest frequency of root differentiation was about 60%. The callus failed to differntiate in short-period incubation in higher concentration of 2, 4-D, but when it was transferred to lower level, roots could be initiated. Shoot and plantlets were regenerated from callus cultured in several phytohormone combinations and under different conditions. But the frequency of shooting was very low, and some seedling were morphologically abnormal. The nature of shooting is not yet clear and further studies should be carried on. In this paper, causes of failure in the protoplas culture of mesophyll tissue of wheat leaf were also discussed.