MORPHOLOGY OF MARSILEA VESTITA. I. ONTOGENY AND MORPHOLOGY OF THE SUBMERGED AND LAND FORMS OF THE JUVENILE LEAVES

During their ontogeny, the primordia of the juvenile leaves of Marsilea plants in sterile culture develop 1, 2 or 4 marginal meristems, and these, in turn, contribute cells to the young leaf by anti- and periclinal cell divisions. The final leaves are unifid, bifid, or quadrifid, depending on how many marginal meristems develop, and this is determined early in the ontogeny of the leaf. The mechanism which determines whether or not a marginal meristem develops may fluctuate, as shown by the existence of trifid leaves. Two forms of juvenile leaves are produced, those in a liquid medium, which in many respects resemble the adult quadrifid submerged leaves, and those on a solid medium, which in many respects resemble the adult land leaves.     

A CORRELATION BETWEEN THE APICAL CELL AND THE HETEROBLASTIC LEAF SERIES IN MARSILEA

Plants of three species of Marsilea (M. vestita, M. villosa, M. drummondii) were grown in sterile culture under controlled conditions, and stem apices were sampled at one of the three heteroblastic leaf forms typical of this plant: spatulate, bifid, or quadrifid leaves. Statistical analyses were made of the relationship between the area of the apical cell and the leaf form which the plant produces under varied growth conditions. For all three species there is a statistically significant correlation (1% level) between apical cell area and leaf form. The analysis indicates that 83% of the variation in apical cell area in Marsilea vestita, 52% in M. villosa, and 54% in M. drummondii can be related to the change in leaf form. An increase in the glucose concentration of the culture medium increases the average apical cell area, and the addition of the protein synthesis inhibitor 2-thiouracil at concentrations of 10 mg/liter and 25 mg/liter decreases the average apical cell area. A certain average apical cell area is necessary for the production of a particular leaf form in the series. The area is a relative rather than an absolute size under any one particular growth condition. Any growth condition which inhibits or reverses the increase in apical cell size (which is typical of the normal growth pattern) will inhibit or reverse the normal heteroblastic series. Under constant conditions, the average size at which particular leaf forms develop appears to be species specific. These results confirm a generally held idea that the apex size is related to the heteroblastic leaf series, and they indicate that the area of the apical cell is the key factor rather than the volume or the number of cells of the apex. Undoubtedly the area of the apical cell is only a reflection of the physiological or morphological characteristics of the apical meristem that underlie the heteroblastic leaf series and which currently do not appear to lend themselves to more direct quantitative analysis.     

Effect of Restricted Root Growth on Carbohydrate Metabolism and Whole Plant Growth of Cucumis sativus L

The effects of varied rooting volumes on root growth and source leaf carbohydrate metabolism were studied in greenhouse-grown cucumber (Cucumis sativus L cv Calypso) plants. Plants were grown for 7 weeks in container volumes that ranged from 0.4 to 5.9 liters. Plants grown in the smaller containers exhibited less leaf expansion, lower root and shoot weight, and fewer lateral stems than plants grown in the 5.9 liter containers. Shoot/root ratio was not altered by the container volume, suggesting coordination of root and shoot growth due to rooting volume. Source leaf carbon exchange rates, assimilate export rates, and starch accumulation rates for plants grown in 0.4 liter containers were approximately one-half or less in comparison to those for plants grown in 5.9 liter containers. Starch concentrations per unit leaf area were maintained at high levels in source leaves of plants grown in 0.4 liter containers over the entire day/night cycle. Lower extractable galactinol synthase activities and higher galactinol concentrations occurred in leaves of plants grown in 0.4 liter container volumes. The reduced sink demand, induced by restricted root growth, may have led to increased starch concentrations and to a reduction in stachyose biosynthesis in cucumber source leaves.     

IN VITRO DEVELOPMENT OF THE ISOLATED SHOOT APICAL MERISTEM OF ANGIOSPERMS

Development of complete plants was achieved from isolated shoot apical meristems of Nicotiana tabacum L., Daucus carota L., Nicotiana glauca Grah., Tropaeolum majus L., and Coleus blumei Benth. The explants consisted of only meristematic dome tissue with no visible leaf primordia. A simple nutrient medium composed of the Murashige and Skoog salt mixture, 100 mg/liter myo-inositol, 0.4 mg/liter thiamin-HCl, 1-2 mg/liter IAA, 30 g/liter sucrose, and 1% agar was adequate. Histologically there occurred principally tissue enlargement during the first 3-6 days, followed by appearance of bipolar organization in 6-9 days and formation of a well-defined root apex and initiation of first leaf primordium by 12 days.     

DEVELOPMENTAL ANATOMY OF DIRECT SHOOT ORGANOGENESIS FROM LEAF PETIOLES OF VITIS VINIFERA (VITACEAE)

The anatomy of direct shoot organogenesis from leaf petioles of Vitis vinifera cv. French Colombard cultured in vitro was studied by light microscopy. Regenerating petiole stubs were fixed at 2- or 3-day intervals and sectioned longitudinally. By day 3 on regeneration medium, new cell divisions were observed. After 6 days, three distinct regions of meristematic activity were apparent within the expanding petiole stub: the wound-response, organogenic, and vascularization regions. In the organogenic region, rapid periclinal divisions of vacuolate outer cortical cells formed nodular bumps, many of which developed vascular strands and marginal meristems and formed adventitious leaves. Promeristems with small, densely staining cells and a distinct tunica layer also originated in the organogenic region, by cell division in the epidermal and subepidermal cell layers. With vascularization and the formation of leaf primordia, many promeristems became adventitious shoot meristems. Adventitious leaves and promeristems were initiated continuously from day 10 until day 33. Promeristems were often initiated near or upon adventitious leaves but could form either before or after the adventitious leaf developed. Adventitious leaves and shoot meristems developed vascular connections with the vascular bundles of the original expiant. The implication of this pattern of regeneration for Agrobacterium-mediated transformation of Vitis is discussed.     

Allometric relationships ofmalva parviflora growing in two different bioclimatic regions

A total of 660 individual plants ofMalva parviflora, a medicinal plant in many countries, growing in two bioclimatic regions were randomly collected with the aim of examining the differences in the allometry of this herbaceous plant growing in two bioclimatic regions. Allometric relationships were found in plant height, stem width, leaf area, leaf length, leaf width, petiole length, and leaf dry weight whereas no relationship was found between plant height or petiole length with specific leaf area. Plants growing in the cool bioclimatic region showed that plant height increases more than the increase in stem width, leaf length, leaf width, and petiole length while plants growing in the warm bioclimatic region showed that plant height increase was lower than that of stem width, leaf length, leaf width, and petiole length. Plant height relationship with root length indicated that in the cool region the plant height increase was less than the increase in the root length while the opposite occurred in the warm region. These differences can be explained by the effects of the different environmental conditions present in the two bioclimatic regions such as water scarcity and availability on the growth ofM. parviflora.     

PRIMORDIAL LEAF AND PHYTOHORMONE EFFECTS ON EXCISED SHOOT APICAL MERISTEMS OF COLEUS BLUMEI BENTH.

Coleus blumei Benth. apical meristems and apical meristems +1, +2, +3 primordial leaf pairs were cultured to examine phytohormone influences on development and correlative effects of developing primordial leaves on in vitro responses. The meristem with no phytohormones or low levels of IAA could not develop in vitro. At least 0.1 mg/l IAA and optimumly 1-2 mg/l IAA were required for development into complete plants. IAA from 0.1 to 3 mg/l also resulted in root development with no apparent leaf or shoot formation. Levels of IAA higher than 3 mg/l were inhibitory to development. Kinetin, as a substitute for naturally occurring cytokinins, alone (0.0003 to 3 mg/l) resulted in development of rosettes of leaves. In the presence of IAA (***1 mg/l) and kinetin (0.003 mg/l) plants, rosettes, individual leaves with roots, and roots developed from isolated meristems. Glutamine and adenine sulfate both appeared inhibitory to meristem development. With +1, +2, +3 developing primordial leaf pairs left attached to the apical dome, three pairs were required for plant formation in the absence of phytohormones. In the presence of IAA, two pairs of primordial leaves resulted in plant formation; whereas, with IAA and low levels of kinetin one pair of primordial leaves was enough. Higher levels of kinetin were inhibitory to plant development with primordial leaves present. ABA appeared to be inhibitory to development of meristems and meristems +1, +3 primordial leaves at low concentrations and resulted in death at ***1 mg/l. Developing primordial leaves appear to supply the apical meristem with a balance of phytohormones during growth. Meristem development into a plant first involved formation of leaf primordia. Establishment of a bipolar axis with root formation followed.     

Studies on leaflet abscission of blue lupin leaves

Summary In blue lupin leaves, each leaflet abscises at an abscission zone situated in the pulvinus at its base. The time to abscission of leaflets of detached leaves is proportional to leaf age. Light accelerates abscission; within certain limits the acceleration is the greater the younger the leaf. At a given concentration, kinetin applied to a single leaflet accelerates leaflet abscission in young leaves kept in darkness, delays it in older ones. There is an interaction between kinetin and light which is dependent also on leaf age and kinetin concentration. The leaf can be considered as consisting of three regions, the petiole, the pulvinar region and the leaflets. The effects of kinetin and of light as well as their interactions depent on the regions of the leaf treated with these agents. Kinetin applied to a leaflet of a young leaf kept in darkness accelerates abscission, but kinetin applied to the pulvinar region of a similar leaf kept in darkness delays abscission. When any part of a leaf is illuminated, abscission is accelerated. The most light-sensitive region of the leaf is the pulvinar region, despite its relatively small area. Acceleration of abscission by light is greatest when illumination of the pulvinar region is combined with illumination of either the leaflets or the petiole. The interaction of light with kinetin is complex. Where the illuminated area includes the pulvinar region, kinetin delays abscission. This effect is most marked in the case where the pulvinar region alone is illuminated and kinetin is applied to a leaflet.Intrafoliar abscission as found in lupin leaves permits study of complex interactions of both distal and proximal stimuli involved in abscission.     

The Structure,Elongation and Thickening of Rhizome in Nelumbo nucifera Gaertn

The seedling of Nelurnbo nucifera is erect and its internodes are very short with four Alternately arranged floating leaves. During the juvenile stage, the shoot elongates remarkably and forms the horizontal rhizome. Each leaf grows out from the dorsal side of the node of the rhizome. There are two kinds of terminal buds in the juvenile shoot. (1) vegetative bud and (2) mixed bud. The axillary scale is the derivative part of the leaf. It forms an ochrea around the terminal bud. The winter buds on the annual shoot are all mixed buds. The vessels are absent in the rhizome and no cambium exists. During tile early growth of the rhizome, the rib meristems contribute mainly to the internode elongation. Later however, divisions are seen to commence in the parenchymatous tissue of the internode. As a result of these divisions the internode becomes elongated. The tuberization of the rhizome is built up from cell divisions of three kinds of tissues: (1) primary thickening meristems, (2) cells of the vascular bundles and (3) parenchyma of cortex. But, the growth in thickness of the rhizome seems to be chiefly due to the enlargement of parenchymatous cells.     

莲的根茎构造,伸长与增粗

莲 (Nelumbo nucifera)种苗的茎短而直立,叶互生。幼苗期茎延伸成横卧根茎,其上生有营养芽及混合芽。腋生鳞片为叶的衍生部分,形如叶鞘状,包着预芽。年苗上的冬芽内全为混合芽。根茎内的维管束分散排列,无导管及形成层存在。节间延长通过肋状分生组织及节间内的薄壁组织细胞分裂与增长来完成。根茎可由初生加厚分生组织,维管束细胞,皮层薄壁细胞等的细胞分裂,使层次增加,但增粗主要是由皮层薄壁细胞体积显著增大而引起的。     

Production and nitrogen responses of the African dwarf shrub Indigofera spinosa to defoliation and water limitation

Summary The dwarf shrub Indigofera spinosa Forsk. (Papilionacea), a native forage species of arid Northwest Kenya, was propogated from seed, grown in a controlled environment, and subjected to three treatments of defoliation and watering frequencies in a factorial experimental design. Biomass production and nitrogen accumulation in tissue components were measured to determine defoliation responses in a water-limited environment. We hypothesized that plants would maintain biomass and nitrogen flows despite removal of aboveground meristems and tissues by defoliation. Principal experimental results included a slight reduction (11%; P=0.08) of total biomass production by clipping ca. 1/3 or 2/3 of new leaves and stems and all apical meristems every month. Total aboveground production was not affected by clipping, while final root biomass was reduced 17% by the 2/3 clipping. The least water stressed plants were affected most negatively by defoliation, and the unclipped plants responded more negatively to greater water limitation. Plants achieved partial biomass compensation through alterations in shoot activity and continued allocation of photosynthate to roots. A smaller fraction of leaf production was directed to litter in clipped plants although clipping only removed the youngest tissues, suggesting that clipping increased leaf longevity. In turn, each leaf probably contributed a greater total quantity of photosynthate. Photosynthetic rates were also likely to have been increased by clipping water-stressed plants. In contrast to biomass, plants overcompensated for nitrogen lost to defoliation. Total nitrogen uptake by individual plants was stimulated by defoliation, as there was more total nitrogen in leaves and stems. Increased nitrogen uptake was achieved by clipping stimulation of total uptake per unit of root rather than of total root mass.     

Decomposition and mineralization of <Emphasis Type="Italic">Eichhornia crassipes</Emphasis> litter under aerobic conditions with and without bacteria

The water hyacinth (Eichhornia crassipes (Mart.) Solms.) plants in lakes and reservoirs have gained considerable attention in tropical and sub-tropical parts of the world due to its rapid growth. The amount of nutrients released from the dead plant materials is of particular interest. Thus, decomposition of water hyacinth plant parts under aerobic conditions was studied in the laboratory. Roots, petioles, and leaves of water hyacinth were enclosed separately in one litre polypropylene bottles which contained 500 ml of lake water. To study the influence of bacteria on the decomposition, antibiotics were added to half of the bottles. We observed that decomposition of leaves and petioles without antibiotics were relatively rapid through day 61, with almost 92.7 and 97.3% of the dry mass removed, respectively. Weight loss due to bacterial activities during 94 days decomposition was 22.6, 3.9, and 30.5% from leaf, petiole, and root litter. Decomposition of litter in lake water indicated that after 94 days 0.6, 0, and 0.6 g m^–2 of leaf, petiole, and root N was dissolved in leachate, while 23.1, 14.4, and 6.0 g m^–2 of leaf, petiole, and root N was either volatilized or remained as particulate organic N. Moreover, 0.2, 0, and 0.1 g m^–2 of leaf, petiole, and root P remained dissolved in the leachate, while 3.1, 3.4, and 1.1 g m^–2 of leaf, petiole, and root P was either precipitated or remained as particulate organic P. The carbon dynamics during the decomposition indicated that 7.4, 28.8, and 3.7 g m^–2 of leaf, petiole, and root C remained dissolved in the leachate after 94 days while 228.0, 197.6, and 107.4 g m^–2 of leaf, petiole, and root C was either diffused or remained as particulate organic C. These findings are useful for quantifying the nutrient cycles of very shallow lakes with water hyacinth under aerobic water environment. Further examination of the fate of the plant litter as it moves down in deep anaerobic water environment, is necessary to understand the leaching process better.     

POPULATION STRUCTURE IN ZAMIA DEBILIS (ZAMIACEAE) I. SIZE CLASSES,LEAF PHENOLOGY,AND LEAF TURNOVER

Population structure, leaf phenology and leaf turnover were followed over a 29-month period in Zamia debilis L.f. ex Aiton (Zamiaceae), an understory species in the Cambalache Forest in northern Puerto Rico. It was not possible to determine plant age or to measure the subterranean stems; size classes based on leaf number and leaf × leaflet number indices were used to determine population structure. Despite seasonal and year to year fluctuations in leaf number at the individual and population level, population profiles remained relatively constant. At any one time, over 50% of the population was composed of unbranched individuals with one or two leaves. Only 7% of the plants were branched. Plants with seven or more leaves comprised at a maximum 8% of the population, but accounted for 28% of the total foliage. Size classes based on leaf number and on a leaf × leaflet index gave approximately reverse J-shaped curves typical of trees with shade tolerant seedlings and saplings. New leaves emerged throughout the year, with a peak at the beginning of the rainy season in May or June and lowest production during the dry months of February through April. Average leaf life expectancy was approximately 2.3 years. Leaf death occurred over an extended period of time by the loss of individual leaflets. Patterns in leaf production and loss differed between few- and many-leaved plants. On the average, as the number of mature leaves on a plant increased, time between emergence of new leaves decreased. In many-leaved plants more than one event of new leaf emergence per year was common. Individuals with one to three mature leaves and individuals with four or more mature leaves differed in their response to water stress: few-leaved plants generally reduced the rate of new leaf production and retained old leaves longer. Plants with more than three leaves continued to produce new leaves, but the rate of leaf mortality increased so that most had a net leaf loss. There was no evidence that leaf emergence or retention were affected by cone production or seed maturation.     

不同荷花品种出泥部分与根状茎生长性状和部分生理指标的比较及相关性分析

在盆栽条件下,对不同荷花(Nelumbo nucifera Gaertn.)品种〔藕莲品种'大紫红'('Dazihong')、花莲品种'中国红·上海'('Zhongguohongshanghai')和花藕兼用莲品种'逸仙莲'('Yixianlian')〕出泥部分(叶和花)和泥下部分(根状茎)的生长性状和部分生理指标进行了比较研究,并对3个荷花品种出泥部分与根状茎间的生长性状和部分生理指标进行了相关性分析.结果表明:'大紫红'在整个生长发育期不开花;'中国红·上海'开花时间相对较早(6月上旬),花重瓣且色泽鲜艳;'逸仙莲'开花时间相对较晚(7月上中旬),花单瓣呈白色.3个荷花品种中,'大紫红'立叶数最少,立叶面积最大,根状茎膨大明显,根状茎中可溶性糖和可溶性蛋白质含量最高;'中国红·上海'立叶数最多,立叶中叶绿素含量最高,根状茎节间长度最长,但根状茎膨大不明显;'逸仙莲'立叶数居中,叶柄最长,根状茎膨大明显,根状茎中可溶性蛋白质、可溶性糖、淀粉和维生素C含量介于其他2个荷花品种之间.相关性分析结果表明:荷花立叶面积与根状茎节间长度呈显著负相关,而与根状茎中可溶性糖、可溶性蛋白质及维生素C含量呈极显著或显著正相关;叶柄长度与根状茎直径和根状茎节间质量呈显著正相关;立叶中叶绿素含量与根状茎节间长度和根状茎中淀粉含量呈显著正相关,而与根状茎中可溶性糖含量呈显著负相关.研究结果显示:根据供试3个荷花品种的立叶面积、叶柄长度、立叶中叶绿素含量可间接判断根状茎的生长发育及营养品质状况,并可进一步应用于快速选育花藕兼用莲品种.     

The<Emphasis Type="Italic"> Arabidopsis thaliana rlp</Emphasis> mutations revert the ectopic leaf blade formation conferred by activation tagging of the<Emphasis Type="Italic"> LEP</Emphasis> gene

Activation tagging of the gene LEAFY PETIOLE ( LEP) with a T-DNA construct induces ectopic leaf blade formation in Arabidopsis, which results in a leafy petiole phenotype. In addition, the number of rosette leaves produced prior to the onset of bolting is reduced, and the rate of leaf initiation is retarded by the activation tagged LEP gene. The ectopic leaf blade results from an invasion of the petiole region by the wild-type leaf blade. In order to isolate mutants that are specifically disturbed in the outgrowth of the leaf blade, second site mutagenesis was performed using ethane methanesulphonate (EMS) on a transgenic line that harbours the activation-tagged LEP gene and exhibits the leafy petiole phenotype. A collection of revertant for leafy petiole ( rlp) lines was isolated that form petiolated rosette leaves in the presence of the activated LEP gene, and could be classified into three groups. The class III rlp lines also display altered leaf development in a wild-type (non-transgenic) background, and are probably mutated in genes that affect shoot or leaf development. The rlp lines of classes I and II, which represent the majority of revertants, do not affect leaf blade outgrowth in a wild-type (non-transgenic) background. This indicates that LEP regulates a subset of the genes involved in the process of leaf blade outgrowth, and that genetic and/or functional redundancy in this process compensates for the loss of RLP function during the formation of the wild-type leaf blade. More detailed genetic and morphological analyses were performed on a selection of the rlp lines. Of these, the dominant rlp lines display complete reversion of (1) the leafy petiole phenotype, (2) the reduction in the number of rosette leaves and (3) the slower leaf initiation rate caused by the activation-tagged LEP gene. Therefore, these lines are potentially mutated in genes for interacting partners of LEP or in downstream regulatory genes. In contrast, the recessive rlp lines exhibit a specific reversion of the leafy petiole phenotype. Thus, these lines are most probably mutated in genes specific for the outgrowth of the leaf blade. Further functional analysis of the rlp mutations will contribute to the dissection of the complex pathways underlying leaf blade outgrowth.Communicated by G. Jürgens     

Evidence for a revertant at the La locus in regenerating hypocotyl segments in tomato

Summary Leafy and leafless phenotypes were regenerated in vitro from hypocotyl segments of leafless forms (reduced and modified) of the homozygous lanceolate (La) mutant in tomato. Segregation of progeny of leafy regenerates into homozygous. mutant (La La), heterozygote (La La ⁺) and normal (La ⁺ La ⁺) indicates that cells forming the shoot apical meristems undergo a genetic reversion, and that the nutrient medium might be selecting for the heterozygote. Among the progeny of the regenerates is a true breeding, unlobed variant. Leaves of the variant are pinnately compound and the margins are entire. Opposite cotyledons followed in development by two simple leaves before the appearance of a pinnately compound leaf with an occasional lanceolate-shaped leaflet suggests that the unlobed variant is morphologically intermediate between La La ⁺ and La ⁺ La ⁺.     

Diurnal oscillatory movements of growing leaves of tobacco

The analysis of diurnal oscillatory movements of tobacco leaves was used in the diagnosis of viral infection of plants. The oscillatory helices circumscribed by a growing leaf of a healthy plant were regular, but some deviations, particularly in the transition points, were recorded. In order to make clear the cause of these irregularities of trajectory, the course of elongation of leaf petiole and blade in relation to localization and shift of zones of elongation during ontogenesis was analysed. The present analysis is similar to that described by the author's earlier experiments with pea roots. Oscillatory curves circumscribed by petiole, projected on a horizontal plane, were compared with curves circumscribed by the blade tip. The analysis of the leaves of different ages enabled us to study this process in dependence on growth rate. It was confirmed that oscillations are a result of elongation; the extent of oscillations is quantitatively dependent on the growth rate. An analysis of the zones of growth showed that in petiole the active meristems are localized near to its base while in the leaf lamina they move gradually during the ontogenesis from the apical to the basal part of the leaf blade. Active meristems of young rapidly growing leaves are localized approximately in the middle of the blade while those of old leaves were found in close proximity to the base of the lamina. The growth rate of petiole can be expressed in hundreds of mm per hour (4.8×10^?2 mm h^?1); half of this value was recorded for its apical part. The growth rate of leaf blade was found approximately ten times higher (3.2×10^?1 mm h^?1). The oscillatory movements of growing leaf consists of two integrate components: of oscillations originating in the base of the petiole and of oscillations of leaf blade the centrum of which is localized in the basal third of the blade. The arrangement of the experiments did not enable us to determine to what extent the phototropic response of leaf blade participates in leaf movements. The movements of leaves of an intact plant are evidently affected by rhythmic stem oscillations. Stem is an integral part of a system which participates in the transfer of information in plants.     

MORPHOLOGY OF MARSILEA VESTITA. III. MORPHOGENESIS OF THE LEAVES OF ETIOLATED PLANTS

The laminae of etiolated Marsilea vestita leaves develop by means of marginal meristems. Unlike light-grown plants, the form of the etiolated plant is not affected by growth on a solid medium. All of the young leaves isolated from light-grown submerged plants will elongate in darkness. The smallest, etiolated, uncoiled leaves develop into land leaves when they are placed in light, and this development occurs regardless of whether the leaves remain on the plant or are isolated on nutrient agar. Only these smallest leaves (2.3 mm average length) are actually capable of being converted from a submerged leaf form to a land leaf form by darkness.     

茅苍术愈伤组织诱导及其细胞悬浮培养研究

采用正交试验法研究了不同的植物生长调节剂对茅苍术叶柄、叶片和根茎愈伤组织诱导的影响,结果表明,不同外植体在各自的最佳培养条件下,叶柄、叶片和根茎愈伤组织的诱导率分别为99.0%、83.5%和71.5%,以叶柄的培养效果最好,其中2,4-D对茅苍术愈伤组织的诱导具有极显著的效果,在各种植物生长调节剂组合中,诱导叶柄愈伤组织形成的最佳组合为0.4mg·L-1NAA、4.0mg·L-12,4-D和0.4mg·L-1KT,培养20d左右,诱导率达到99.0%。此外,将茅苍术叶柄细胞悬浮培养至18d时,细胞量、多糖和苍术素的含量均达到最大值,分别为9.07g·L-1、15.68mg·L-1和19.62ug·L-1。     

Population ecology in a natural<Emphasis Type="Italic">syneilesis palmata</Emphasis> stand: II. vegetative growth and population structure

Vegetative growth and changes within populations ofSyneilesis palmata (THUNB>) MAX. Usannamul were monitored in two natural stands with different levels of incoming light. This perennial, shade-tolerant herb was measured for its plant size, petiole length, leaf breadth, and leaflet number over 11 years in a moderately shaded (MS) stand and over 7 years in a severely shaded (SS) stand. At the end of each growing season, a shoot primordium developed at the center of the root system. Correlation coefficients were mostly high between pairings of two properties - total weight, petiole length, petiole weight, leaf breadth, leaf blade weight, leaf area, specific leaf area, and leaflet number. Mean annual mortality of this species was higher in SS (22.97%) than in MS (8.85%), but great fluctuations were seen from year by year. Mortality was lowest for medium-sized plants. Regarding petiole length, differences in mean annual growth rates were conspicuous, i.e., 2.6% in MS and 8.4% in SS, while growth rates for leaf breadth were 3.1% in MS and 24.2% in SS. Changes in plant frequency within individual size classes roughly showed a normal distribution curve. However, the mode varied year by year, and such changes were more remarkable in SS than in MS. Under severe shading,S. palmata had a higher growth rate and but also greater mortality than did plants under moderate shade. Therefore, one can conclude that the population structure in SS was unstable over time.