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1.
航天诱导凤仙花SP3代子叶变化的研究   总被引:2,自引:0,他引:2  
“神舟4号”搭载的凤仙花(Impatiens balsamina)种子经种植后获得SP3种子,发现SP3代子叶发生变异现象,在苗期的子叶数目和形态呈多种变化。除绝大多数为正常的2片大小相等的子叶外,还出现了少数三子叶、漏斗状子叶(杯状子叶)和联生子叶。在子叶的大小上,有的2片子叶大小基本相似,有的则差异明显。在子叶变异的植株中,有的植株叶片大小、花的形态和育性发生了变化,没有结果,不能通过有性繁殖后代。子叶的变异是遗传原因还是生理影响尚需进一步研究。  相似文献   

2.
对云南泸西栽培灯盏花群体进行调查,发现了灯盏花雄性不育种质个体,其出现频率约为1.06×10-4.对所发现的灯盏花不育株形态特征及其花药发育过程进行了观察,并对花粉活力进行鉴定.结果显示:(1)灯盏花不育株根、茎、叶形态与正常可育植株基本相似,管状花小,花丝短,花药瘦小,无花粉粒散出或花粉无活力.(2)灯盏花在其花药发育的小孢子母细胞时期、四分体时期、小孢子时期和单核早期,由于绒毡层细胞液泡化、提前解体,不能为小孢子或花粉发育提供所需物质,导致小孢子母细胞和四分体解体,产生无花粉的花药;或小孢子和单核花粉胞内降解,形成不同形状和外壁纹饰的败育花粉.研究认为,灯盏花花药绒毡层异常是其花粉败育的主要原因.  相似文献   

3.
为探讨生境对卷柏属(Selaginella)植物微观形态的影响,利用扫描电子显微镜对海南七仙岭采集的7种卷柏属植物的侧叶、中叶、孢子叶的叶表皮形态以及小孢子形态进行全面观察分析,并计算气孔器大小、气孔密度、孢子大小等,比较分析其微观形态的区别及微形态与生境间的关系,为卷柏属植物的分类提供依据。结果显示:(1)同种卷柏属植物的侧叶、中叶与孢子叶在叶表皮形态上具明显差异,尤其是孢子叶上的气孔与营养叶相对较小且稀疏,与孢子叶的繁殖功能相符合。(2)不同种卷柏属植物的叶表皮特征也明显不同,主要表现在叶缘刺、气孔和瘤状突起上,表明这些特征可以作为卷柏属植物种间区分的依据。(3)卷柏属植物的小孢子形态稳定,纹饰多样;部分种间的小孢子形态相似,但可通过纹饰类型、裂缝的曲直进行区分。(4)琼海卷柏的小孢子具有独特的网状纹饰,暗示其具有独特的演化途径。(5)卷柏属植物叶表皮的气孔特征、瘤状突起特征,小孢子的颜色、纹饰,与海拔、生境的湿度有一定的相关性,但其形成机理有待进一步研究。  相似文献   

4.
对杉木雄性不育株外部形态和细胞学研究结果表明:不育株叶色较绿;小孢子叶球簇苞片和小孢子叶异常张开,使其小孢子囊发育过程中的温湿条件不恒定;其小孢子叶球发育推迟;导致其小孢子发生和发育异常;小孢子囊外常有一包被结构和中层细胞增生以及小孢子叶球发育后期苞片和小孢子叶张开度小,使囊内细胞受挤压而引起囊内各种细胞生理代谢的异常和解体;曲枝和小枝输导组织、小孢子叶球轴维管束及小孢子叶球和小孢子叶的树脂道的不发达,以及小孢子叶球中各种细胞内淀粉粒的缺少或畸形、中层和绒毡层细胞内线粒体和内质网的异常等,都是引起雄性败育的原因之一。  相似文献   

5.
周洋  杨章旗  黄永利 《广西植物》2020,40(4):482-491
为了解湿地松‘松泰’小孢子叶球在发育过程形态是否有差异变化,明确其败育过程、败育方式及影响因素,为湿地松雄性不育品种利用和后期开展相关研究提供科学依据。该研究以‘松泰’s10败育系和s9可育系为材料,观察小孢子叶球形态发育变化,并对其小孢子叶球进行石蜡切片,在光学显微镜下观察小孢子发育过程。结果表明:s10败育系和s9可育系在小孢子母细胞减速分裂前无明显差异,小孢子叶球生长趋势也一致;四分体时期,s10小孢子细胞发育异常,小孢子叶球形态发育也出现异常,二者异常发育具有同步性;可育系从四分体到单核小孢子发育阶段的时间为5 d左右,而败育系持续发育长达20 d左右,持续时间为可育系的4倍。在此期间出现小孢子绒毡层细胞发育异常、降解缓慢,小孢子囊壁组织排列紊乱、降解延迟等现象,s10形成异常二核花粉,且无花粉散出。因此,推论s10小孢子败育的原因主要是小孢子囊壁细胞发育异常,其小孢子叶球形态异常,相对应的绒毡层在四分体时期发育异常,不能适时地分泌胼胝质酶来降解围绕着四分体的胼胝质壁,也不能适时地合成输送花粉形成所需能量物质,同时囊壁细胞出现降解延迟和层积,这一系列的异常变化导致不能形成正常四分体,从而使花粉败育。  相似文献   

6.
在开展苏铁Cycas revoluta形态特征观测中,发现一株苏铁根蘖苗有5片羽片生长异常,其中一片比其他正常羽片长且中脉出现分叉(即一羽多脉现象),另外4片基部两两贴生。另一株苏铁的小孢子叶球生长奇特,其顶部为莲座状,形似大孢子叶球。这两种异常现象为苏铁类植物的系统分类与演化研究提供了新资料。  相似文献   

7.
攀枝花苏铁传粉生物学研究   总被引:10,自引:0,他引:10  
在攀枝花苏铁(Cycas panzhihuaensis L.Zhou et S.Y.Yang)自然群体中,雌雄株在数量上基本相等,但雄株的无性系产量是雌株的1.31倍,小孢子叶球的数量是大孢子叶球的2.21倍,呈现偏雄现象。小孢子叶球散粉次序是从轴基部向顶部和从小孢子叶的基部向顶部进行的,散粉高峰出现在午后,风传花粉浓度在2.55m内随着距离增加而迅速下降,而在2.55m以外维持在一个较低的水平上。在大孢子叶球内发现有两种蚂蚁和一种蜚蠊类昆虫在活动,没有发现这些昆虫对大孢子叶球的破坏,小孢子叶球则几乎没有昆虫探访。清晨在大孢子叶叶片上出现许多水样液滴,可能起着将大孢子叶叶片上沉积的花粉传递至胚珠的作用。研究表明,在攀枝花苏铁的传粉过程中,风是将花粉从小孢子叶球传至大孢子叶球的唯一媒介,大孢子叶球内活动的昆虫和大孢子叶叶片上的液滴同样起着传粉媒介作用,但不排除风传花粉一步到位的可能性。  相似文献   

8.
作者于1978年从福建省福州市西湖公园的芒果花中分离出一株酵母1519。该菌株不产生子囊孢子、掷孢子,亦未见到有锁状连合。未发现有性繁殖。无性繁殖是在母细胞上产生小梗,小梗上产生子细胞,子细胞还可再生小梗再生子细胞。如果子细胞不脱落则成链状或分枝的链状。不发酵任何糖。按照形态和繁殖特征只符合Lodder(1970)酵母分类专著中半知菌部分的梗孢酵母。因此将它放入梗孢酵母属,命名为福州梗孢酵母(Sterigmatomyces fuzhouensis sp.n.)。  相似文献   

9.
王旋  陈艳  刘志雄 《广西植物》2022,42(1):133-142
为从形态上研究甜荞(Fagopyrum esculentum)二型花发育的差异性,该文运用石蜡切片技术对甜荞pin型花和thrum型花大、小孢子发生和雌、雄配子体的发育过程进行观察比较。结果表明:(1)甜荞2种花的雌蕊、雄蕊发育的细胞学特征有很高的相似性,具直生胚珠、双珠被、厚珠心;大孢子四分体直线型排列,合点端为功能大孢子,蓼型胚囊。花药4室,花粉囊壁由表皮、药室内壁、一层中层和一层绒毡层组成,其中绒毡层发育为腺质型,小孢子母细胞减数分裂过程中的胞质分裂为同时型,小孢子四分体常为四面体型,但thrum型花花粉囊中偶见十字交叉型小孢子四分体;成熟花粉粒多数为2细胞型,少数为3细胞型。(2)从2种花雌蕊、雄蕊的发育进度来看,与pin型花相比,thrum型花小孢子发育相对较慢,雄配子体发育较快,但开花时,两者雌蕊、雄蕊均发育成熟。(3)综合甜荞两种花生殖发育的过程来看,其有许多相对原始的胚胎学特征,但也出现一些如直生胚珠、3细胞型花粉等相对进化的性状。该研究完善了甜荞二型花生殖发育的形态细胞学资料的同时,也为理解石竹目物种间的亲缘关系提供了胚胎学证据。  相似文献   

10.
古莲的研究现状及意义(二)   总被引:1,自引:0,他引:1  
(续1999年第11期第2页)  莲在我国古籍文献记载中,也至少有3000多年的历史了。公元前1000多年的《诗经·郑风》中记有:“山有扶苏,湿有荷华”,“彼泽之陂,有蒲有荷”。可见在当时我国大地上有水泽的地方,已有莲的生长。我国古籍中关于“莲”的记载很多,莲在我国出土文物中,至少已有7000年历史。4.2 古莲的形态特征和染色体结构研究 莲是一种古老的双子叶植物,又具有单子叶植物的某些性状,主要反映在它的形态特征上。它的2枚基部合生的子叶,2片先出叶(幼叶)互生,二歧分枝式叶脉;实生苗“之”字…  相似文献   

11.
The quantitative distribution of the flavanone-7-neohesperidoside, naringin, in seeds, seedlings, young plants, branches, flowers, and fruit of Citrus paradisi Macfad., cv `Duncan' was analyzed by radioimmunoassay. High levels of naringin were associated with very young tissue and lower levels were found in older tissues. Seed coats of ungerminated seeds and young shoots had high naringin concentrations whereas cotyledons and roots had very low concentrations. Light-grown seedlings contained nearly twice as much naringin as etiolated seedlings and, in young plants and branches, the naringin content was highest in developing leaves and stem tissue. In flowers, the ovary had the highest levels of naringin, accounting for nearly 11% of the fresh weight. There was a net increase in the total naringin content of fruits during growth. However, due to the large increase in fruit size, there was a concomitant decrease in the naringin concentration as the fruit matured.  相似文献   

12.
In Catasetum viridiflavum Hook., a drought-deciduous orchid from central Panama that produces unisexual flowers, plants possess up to nine annually-produced pseudobulbs. I investigated the role of these structures in plant growth and flowering by 1) relating annual shoot size and flower production to the size and number of pseudobulbs possessed by plants, 2) experimentally severing connections between young and old pseudobulbs when plants were dormant and monitoring their subsequent vegetative growth and flowering, and 3) determining the seasonal variation in water content, total nonstructural carbohydrates, nitrogen, and phosphorus in pseudobulbs. In small plants (1 to 3 pseudobulbs) pseudobulb stores appeared important to both vegetative growth and flowering. In larger (= older) plants, pseudobulb number was not related to vegetative growth and experimental separations of young from old pseudobulbs did not affect growth. However, flower production by experimental plants was significantly reduced relative to controls. Male plants were usually smaller than female plants in the areas studied; however, experimental reductions of pseudobulb number did not affect the sex expression of plants. All measured nutritional components of pseudobulbs exhibited significant seasonal variation. Carbohydrates appeared most important for supporting growth immediately following dormancy. Nitrogen and phosphorus were less important for this role and may have been more important for determining the number of flowers produced by plants.  相似文献   

13.
When analyzing tobacco lines overexpressing various types of rice phytochrome A, we observed seedlings with fused cotyledons. Phytochrome A is a member of the phytochrome family of plant red/far-red absorbing photoreceptors. Reciprocal crossings with wild-type tobacco indicated that this abnormal phenotype was maternally inherited. Mother plants that were expected to produce abnormal seedlings, were raised under different conditions and seeds collected separately from individual capsules. The frequency of abnormal seedlings increased in seeds from later flowers but decreased when mother plants were raised under continuous white light. The interaction of the overexpressed phytochrome A proteins with endogenous plant hormones might be responsible for cotyledon fusion. The abnormal phenotype could partially be recovered by application of gibberellic acid to intact flowers at the time of pollination. In contrast, the synthetic auxin NAA slightly enhanced the degree of cotyledon fusion. Even wild-type tobacco seedlings exhibited partial fusion of cotyledons if flowers were treated with 2,4-D and occasionally the shoot apex was replaced by a second root. Application of GA3 to the flowers, in contrast, impaired the development of the radicule. These observations are discussed with respect to maternal effects in plant embryogenesis.  相似文献   

14.
Morphological and anatomical features of mature embryos and seedlings were observed at different growth stages in the parasitic angiospermCuscuta japonica Choisy. The spirally coiled embryos from scarified seeds had no cotyledons but possessed blunt radicles. Seeds germinated at 30°C in the dark. Although most embryo cells incubated for 16 h did not have starch grains, the shoot cells of three-day-old seedlings possessed numerous starch grains. After these seedlings were transferred to a lightened growth chamber, all the shoot apical regions of seedlings grown for 6,8, and 10 days became greenish and hooked. Most of the shoot cells, including the green apical parts, contained abundant starch grains. The hooks opened only when one seedling made contact with another seedling. This suggested that the green and hooked shoot apical regions played an important role in searching for and twining about their host plants. In some two-day-old seedlings, the massive roots were circular or semi-circular. This enabled the shoot axes to stand erect on some substratum. It would assist the shoots in making contact with the host plant. In eight-day-old seedlings, the green apical regions also were hooked and the roots were considerably degraded.  相似文献   

15.
J. N. Thompson 《Oecologia》1987,72(4):605-611
Summary Populations of Lomatium grayi (Umbelliferae), an andromonoecious, perennial herb, differe in growth rates, flowering frequency, and survivorship. Effects of these different life histories on the ontogeny of sex expression were analyzed for plants from two populations grown from seedlings in a common garden and monitored for six years. Plants from Smoot Hill, Washington grew faster, had a higher probability of flowering at each age and size after the first year of growth, and a higher probability of flowering repeatedly among years than did plants from Clarkston, Washington. The proportion of plants producing some hermaphroditic flowers increased with plant size in both populations. Smoot Hill plants, however, were more likely to begin flowering as small, staminate plants than Clarkston plants. Clarkston plants did not begin flowering until they were older and larger, and most of these plants produced some hermaphroditic flowers when they began reproduction. The positive association between production of hermaphroditic flowers and both plant size and age was consistent with the hypothesis that hermaphroditic flowers are more costly to produce than staminate flowers.Although the populations did not differ in the total number of flowers per plant produced at any age or size, Smoot Hill plants consistently produced a lower percentage of hermaphroditic flowers than Clarkston plants at larger sizes and later ages. Consequently, selection for faster growth rates and higher flowering frequency at small sizes and early ages may have favored the more staminate-biased sex ratios in the Smoot Hill population.  相似文献   

16.
This study investigates how herbivory by larval insects on fruit of the mangrove Avicennia marina affects the subsequent establishment, growth, and survivorship of its seedlings. Research was done in a temperate mangrove forest in Australia where the larvae of two species of insects were the dominant frugivores: the mangrove fruit fly Euphranta marina and the mangrove plume moth Cenoloba obliteralis. Larvae consumed the cotyledons of fruit, but not their embryonic axes. Damage to the cotyledons of fruit while on the tree was obvious in abscised propagules and the cotyledons of seedlings, indicating that larvae within fruit continue to consume the cotyledons and develop while the propagule disperses and the seedling establishes. We found that 53% of fruit, 69% of abscised propagules, and 80% of the cotyledons of seedlings had been attacked by larval insects. The degree of damage to the cotyledons was positively related to the densities of larvae within the fruit and the number of emergence or exit holes in the surface of the cotyledons. Consequently, the number of exit holes could be used as a proxy for the amount of damage to the cotyledons. An experiment in which we placed propagules with different levels of damage (zero, one, two, or three exit holes) on the forest floor revealed that frugivory did not influence the establishment of seedlings. In another experiment, we monitored the performance of newly established seedlings with cotyledons that had zero exit holes, one or more exit holes, or where we had removed their cotyledons. In both experiments, the growth of seedlings as measured by their heights and number of leaves was negatively related to the degree of frugivory. Consumption of the cotyledons by larvae apparently reduces the energy reserves available for the initial growth of seedlings. The early mortality of seedlings in both experiments was minimal and appeared to be independent of differences in size due to frugivory. Experimentally removing the cotyledons of seedlings produced extremely short seedlings with increased mortality, confirming the importance of cotyledonary reserves to the initial growth and survivorship of seedlings of A. marina. This study highlights how the early life history of plants may be impacted by conditions experienced by the propagules before they disperse from the parental plant.  相似文献   

17.
During studies on the chemistry of plant surfaces, we observed that concomitant with the development of cucumber (Cucumis sativus L. cv `ELEM') cotyledons an agglutinin that agglutinates human erythrocytes appeared on epicuticular surfaces. The agglutinin was released from cotyledon surfaces into distilled water by a 1-minute immersion (or even less). Homogenization of the washed cotyledons released residual agglutinating activity. The surface-located hemagglutinating activity was age-dependent and occurred in dark- and light-grown cotyledons. Agglutinating activities were present in light-grown cotyledons of 2- to 14-day-old seedlings and in dark-grown cotyledons of 3- to 17-day-old seedlings. Agglutinating activities were maximal in cotyledons of 3- to 4-day-old seedlings. No activity could be detected in dry seeds or in seedlings up to 2 days and after 17 days of germination. The hemagglutinating activity was specifically inhibited by N,N′,N″-triacetylchitotriose, chitin, and chitosan.  相似文献   

18.
The activities of adenosylhomocysteinase (EC 3.3.1.1) and adenosine nucleosidase (EC 3.2.2.7) were assayed in extracts from yellow lupin (Lupinus luteus L.) cotyledons at different stages of seed formation and seedling development. Adenosylhomocysteinase activity was demonstrated in all the cotyledon extracts examined. Its lowest level was found in the dry seeds and the highest, in 4-day-old seedling cotyledons. Extracts from the cotyledons of maturating seeds, dry seeds, and seedlings up to the second day of growth exhibited no adenosine nucleosidase activity. Adenosine nucleosidase activity appeared in the cotyledons of 2-day-old seedlings and its highest level was reached in 4-to 5-day-old seedlings. There is no inhibitor of adenosine nucleosidase in the maturating and dry yellow lupin seeds. No activator of a possible zymogen form of adenosine nucleosidase from maturating or dry seeds occurs in the growing seedlings.  相似文献   

19.
The capacity of individual branches to store water and fix carbon can have profound effects on inflorescence size and architecture, thus on floral display, pollination, and fecundity. Mixed regression was used to investigate the relation between branch length, a proxy for plant resources, and floral display of Fouquieria splendens (ocotillo), a woody, candelabraform shrub of wide distribution in arid North America. Long branches produced three times as many flowers as short branches, regardless of overall plant size. Long branches also had more complex panicles with more cymes and cyme types than short branches; thus, branch length also influenced inflorescence architecture. Within panicles, increasing the number of cymes by one unit added about two flowers, whereas increasing the number of cyme types by one unit added about 21 flowers. Because flower production is mediated by branch length, and because most plants have branches of various lengths, the floral display of individual plants necessarily encompasses a wide range of inflorescence size and structure.  相似文献   

20.
Kutík  J.  Wilhelmová  N.  Snopek  J. 《Photosynthetica》1998,35(3):361-367
French bean (Phaseolus vulgaris L.) cotyledons lost most of their reserve substances during several early days of germination and turned green. In cotyledon mesophyll cells of one-week-old seedlings, plastids were represented predominantly by amyloplasts (starch grains) and chloroamyloplasts, and the cells appeared to be metabolically highly active. Cell heterogeneity associated with distance of the cells from cotyledon vascular bundles was evident. Only mesophyll cells near to the bundles were rich in plastids. In two-weeks-old intact bean plants, the cotyledons were yellow and shrunken, and their cells were nearly "empty". The plastids in them were represented by senescent plastids (gerontoplasts) only. In the gerontoplasts as well as freely in cytosol, fluorescent lipoid inclusions were accumulated. This cotyledon development was more or less independent of irradiance. In "decapitated" bean plants, senescence of mesophyll cells and plastids was slowed down considerably, and the life span of the cotyledons was prolonged.  相似文献   

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