半夏珠芽发育过程的形态学和解剖学研究

通过形态学观察和石蜡切片方法研究了半夏[Pinellia ternata(Thunb.)Breit.]的珠芽发育过程,结果显示:半夏珠芽着生于叶柄的下部,起始于幼嫩叶柄的腹面最外轮维管束外周薄壁细胞;恢复分裂的薄壁细胞分裂形成珠芽原基细胞团,在原基生长突破叶柄表皮后分化形成具有生长点的珠芽结构,发育中的珠芽无根分化;珠芽的生长被动地终止于叶片衰老(倒苗),无明显的成熟发育过程。研究表明,半夏的珠芽是不定芽性质的无性繁殖结构,但在发育过程上明显区别于其它植物的珠芽发育。     

滴水珠珠芽发育过程研究

珠芽是滴水珠(Pinellia cordata)的营养繁殖结构,为揭示滴水珠珠芽发育过程中的特征,该研究以野外采集材料进行盆栽观察试验,通过形态观察法和石蜡切片方法,探索滴水珠叶片和叶柄处珠芽发育过程中的形态学和解剖学结构特征。结果表明:滴水珠珠芽发育过程在形态上分为叶柄无现象时期、早期珠芽结构分化和珠芽膨大成熟时期三个时期;相应的解剖学发育时期为珠芽原基启动期和形成期、原基分化期和膨大成熟期四个阶段。叶片和叶柄珠芽起始细胞均由叶柄腹面表皮下层薄壁细胞组织脱分化形成,起始细胞不断分裂形成细胞团最后发育成珠芽原基;在原基分化期的特征是生长点形成,最终分化形成芽原基和鳞片叶;膨大成熟期的特征是珠芽结构不断生长,生长点侧生分化鳞片叶增多。叶片和叶柄处珠芽成熟脱落时期为灰色椭圆形结构,测得平均直径分别为(2.79±0.40)mm和(2.69±0.36)mm,外部有鳞片包裹,内部含大量营养物质。在环境适宜条件下,珠芽遇土萌发,萌发率达75%。这表明滴水珠珠芽与同属植物半夏珠芽发育过程差别不大,都是无性克隆营养繁殖体结构。     

淡黄花百合珠芽发育过程的形态学与解剖学研究

以野生淡黄花百合(Lilium sulphureum)为实验材料,通过形态学观察、石蜡切片方法对珠芽的发生规律、发育过程中的形态学变化及解剖结构特征进行了研究,以阐明淡黄花百合珠芽繁殖的生物学机制。结果显示:淡黄花百合的珠芽形成于地上茎叶腋处叶柄的近基部位置,由叶柄表皮以内数层薄壁细胞不断分裂和分化形成;珠芽的发育过程可划分为启动期、膨大期和成熟期三个时期。成熟珠芽外观上成圆形或椭圆形,珠芽中部的薄壁细胞含有大量淀粉颗粒。淡黄花百合的珠芽具有很高的萌发率(90%以上)。研究表明,珠芽营养繁殖是其生态适应的一种重要机制。     

外界支持物直径对苦瓜生长和觅食行为的影响

采用实验生态学的方法研究了外界支持直径变化对苦瓜植株生长和觅食行为的影响。结果表明,支持物直径变化对主茎节间、叶片、叶柄和卷须的发育进程无明显影响。苦瓜植株的攀援生长显著受到支持物直径大小的影响,当支持物直径小于8mm时,植株能较好地自主攀援生长。生长于直径支持物上的植株比生长于小直径支持物上的植株表现出较高的分枝率、较短的主茎、较长的分枝、较大的比茎长和比叶柄长。相关分析表明,节间长度和叶柄长度同植株自主攀援程度成显著正相关关系,而单叶面积、分枝数量和比叶柄长同植株自主攀援程度成显著负相关关系。作为攀援植物的一种重要资源,外界支持物的特征和存在状况将对植物的生长和行为产生重要影响。     

珠芽魔芋对细菌性软腐病的抗性鉴定研究

采用魔芋Amorphophallus spp.块茎点种、注射、灌根接种及田间调查等方法,对国内普遍栽种的珠芽红魔芋A. bulbifer、珠芽金魔芋A. muelleri、花魔芋A. konjac和白魔芋A. albus等12个种质材料进行抗软腐病鉴定、比较和评价,以分析珠芽魔芋对抗细菌性软腐病的抗病水平。结果表明,供试材料对软腐病抗性差异较大,珠芽金魔芋种质对细菌性软腐病均有免疫性(I),德宏及临沧珠芽红魔芋种质为高抗病品种(HR);缅甸珠芽红魔芋为抗病品种(R);富源花魔芋、楚雄花魔芋、日本农林2号、鄂魔芋1号、秦魔1号、昭通白魔芋、丽江白魔芋均属易感品种(S),与田间抗性调查情况基本相符。     

钙离子对半夏叶柄珠芽位置效应及其生长素含量的影响

研究Ca2+对半夏叶柄珠芽形成位置的影响.在MS+6-BA 1mg/L+IAA 0.5mg/L+3%蔗糖培养基中添加不同浓度Ca2+,观察正置培养的叶柄形芽形成情况并测定内源生长素(IAA含量).结果表明:对照Ca2+为3mmol/L培养基中,珠芽10.56%在其上端生成,92.22%在下端生成;低浓度和高浓度Ca2+对半夏叶柄珠芽形成位置有影响,Ca2+为1.5 mmoL/L和8 mmol/L时影响最显著,正置叶柄的珠芽大多数在叶柄的上端形成,形成率最高达87.22%.内源IAA测定表明:在Ca2+为3 mmol/L培养基中,叶柄上端的I从浓度高于下端,珠芽在下端生成.在Ca2+为1.5mmol/L和Ca2+为8mmol/L时,叶柄上端的生长素浓度低于叶柄下端,珠芽多在叶柄上端生成.因此,叶柄上下两端的生长素浓度差异影响了半夏珠芽的形成位置.     

不同温度处理对珠芽魔芋球茎休眠调控的影响

为探究不同温度处理对珠芽魔芋球茎休眠调控的影响，以珠芽魔芋叶面球茎为材料，在球茎休眠期设置昼/夜变温（24℃/9℃、24℃/13℃、24℃/17℃）、恒温（9℃、13℃、17℃、21℃）及室温处理，萌发期设置26℃、33℃催芽处理，分析不同温度处理后珠芽魔芋球茎在休眠 Ⅰ 期、休眠 Ⅱ 期以及萌发前期、中期、后期、末期的生物表型变化、内源生理变化规律及其休眠调控相关基因的变化情况。结果表明：（1）休眠期恒温处理有利于提高珠芽魔芋球茎的出芽比，其中13℃恒温打破休眠和萌发期33℃催芽处理球茎的发芽率最先达到峰值，且其出芽比最高。（2）休眠Ⅱ期的球茎淀粉含量低于休眠Ⅰ期，而其可溶性糖含量高于休眠Ⅰ期，13℃恒温处理球茎淀粉含量下降最快，其可溶性糖含量最高；前期恒温处理球茎淀粉、可溶性糖含量在萌发前期和萌发后期之间均存在显著性差异（P＜0.05），而前期昼夜变温处理球茎仅可溶性糖含量在萌发前期和萌发后期之间存在显著性差异（P＜0.05）。（3）珠芽魔芋球茎ABA含量在休眠 Ⅰ 期和休眠 Ⅱ 期逐渐增多，而其GA3含量逐渐减少，萌发期珠芽魔芋球茎ABA含量呈现“先升后降”的规律，26℃催芽处理的珠芽魔芋球茎GA3含量呈现“先升后降”的规律，33℃催芽处理的珠芽魔芋球茎GA3含量整体呈上升的趋势。（4）珠芽魔芋NCED基因表达量随着休眠程度的加深逐渐增加，而在萌发期逐渐减少，CYP707A基因表达量随着休眠的加深逐渐减少，而在萌发期表达量增加。研究发现，珠芽魔芋打破休眠的最佳温度为恒温13℃，促进萌发的最佳温度为33℃；随着珠芽魔芋打破休眠，球茎中的淀粉含量降低，可溶性糖含量升高；ABA含量“先升后降”，GA3含量“先降后升”；NCED和CYP707A基因可能是珠芽魔芋休眠调控中的关键基因。     

淡黄花百合的引种驯化与繁殖栽培技术

在武汉对从云南红河州采集的野生淡黄花百合进行引种栽培,研究其物候期、生长发育规律及繁殖栽培技术,为引种栽培提供科学依据。结果表明:淡黄花百合适应性较好,植株生长健壮,开花结实正常,观赏价值高,耐热性良好;通过鳞茎、珠芽、种子繁殖,以珠芽繁殖效果较好;开展基质、施肥对珠芽生长的试验,表明泥炭与珍珠岩比例为1∶1、氮磷钾比例为2∶1∶1的组合对植株成活率、株高以及鳞茎增长等方面均具有显著促进作用,可作为珠芽繁殖的最佳配比,为淡黄花百合的人工繁育提供技术参考。     

不同生境下珠芽蓼（蓼科）的繁殖策略比较

在青藏高原横断山区以海拔相同的高山流石滩和高寒草甸中的珠芽蓼（Polygonum viviparum）居群为研究对象,探讨该物种在不同生境条件下的繁殖策略以及无性繁殖和有性繁殖间的关系。结果发现,流石滩居群的珠芽蓼植株高度和珠芽数量显著低于高寒草甸居群,而珠芽和花总数量、花数量和每个花序上的花比例却显著高于高寒草甸居群。研究结果表明珠芽蓼在环境更为恶劣的高山流石滩生境中增加了对繁殖器官和花资源的投资,说明在高山植物中繁殖优先于营养生长,且有性繁殖比无性繁殖具有更为重要的作用。而对每个植株上花数量和珠芽数量的统计结果表明,两者呈显著的负相关关系,进一步证明了同一植株内无性繁殖和有性繁殖的权衡关系。     

3种薯蓣属植物珠芽糖类含量变化与茎叶生长的关系

以山药、日本薯蓣和黄独3种薯蓣属植物为材料,研究珠芽育苗中其茎叶生长与珠芽内的干物质、淀粉、可溶性糖、还原糖含量和淀粉酶活性变化的关系.结果表明: 3种薯蓣在茎蔓生长过程中珠芽内的干物质和淀粉含量均逐渐降低.山药和黄独的珠芽可溶性糖含量在茎蔓生长初期不断增加,随着茎蔓节数继续增加又逐渐降低,而还原糖含量在叶片展开前不断增加,叶片展开后又急剧降低;日本薯蓣珠芽的可溶性糖和还原性糖含量随着茎蔓节数增加逐渐上升,但保持相对较低水平.3种薯蓣珠芽内α-淀粉酶活性均强于β-淀粉酶,其在茎蔓和叶片生长中发挥重要作用.研究发现,薯蓣珠芽内淀粉主要在α-淀粉酶作用下转化分解为还原糖和可溶性糖,从而为茎蔓和叶片生长提供能量,且还原糖含量与叶片生长的关系更为密切.     

盾叶薯蓣试管株芽的诱导

以盾叶薯蓣(Dioscoreazingiberensis)试管植株为材料,选取带芽茎段为外植体,转接到株芽诱导培养基上15d后,原茎段基部开始产生株芽突起,30d后每一茎段可产生3-5个已生根的株芽,株芽诱导率为100%,株芽诱导数为180个/40株,其移栽成活率可达90%以上。株芽形成的适宜培养条件:温度为26±2℃,光照时间14hd-1,光照强度为1500-2000lx;适宜培养基组成为:MS+6-BA4.0mgL-1+IBA1.0mgL-1+蔗糖6%-9%+活性炭0.5%+琼脂7%。离体诱导的盾叶薯蓣试管株芽能直接发育为新植株,为盾叶薯蓣的快繁提供了一种新的方法。     

Assessment of the effects of environmental change on the performance and density of Bistorta vivipara: the use of multivariate analysis and experimental manipulation

1 Studies of plant performance in relation to local variability in environmental conditions can be used to predict the responses of species to environmental change.
2 We used redundancy analysis to study how interpopulation variation in average plant weight, flower and bulbil number, bulbil weight and population density among 28 populations of Bistorta vivipara was related to variation in 15 environmental factors. We also examined the responses of plants to a 4-year experimental increase in temperature.
3 Significant differences in average plant performance were found between populations. Variance partitioning of the response data showed that environmental factors explained 45% of the variation in plant performance and density between populations, whereas variation due to transect position was small (10.8%). Soil pH, altitude and season length were the most influential of the environmental variables, and explained 23%, 21% and 14%, respectively, of the variation. Plant performance was in general negatively correlated with these variables, whereas plant density increased along the pH and altitude gradients, suggesting that environmental factors associated with elevation (temperature and vegetation cover) and pH (soil fertility) had opposing effects on individual performance and density. Season length was highly important for average bulbil weight.
4 Plants growing in open top chambers had significantly enhanced growth and produced significantly heavier bulbils than those in control plots, whereas flower and bulbil number were unaffected by experimentally increased temperatures. Plant density was equal for warmed and control plots.
5 Although warming may increase bulbil weight and plant size in B. vivipara , the response to climate change is complicated by the fact that population densities may decrease due to intensified competition for light caused by a denser vegetation cover.     

中国兰科羊耳蒜属新记录种——岩生羊耳蒜及其独特的珠芽繁殖方式

报道了中国兰科(Orchidaceae)羊耳蒜属(Liparis Rich.)植物一新记录种——岩生羊耳蒜(Liparis petraea),并提供了其形态描述及彩色图片,凭证标本保存于广西植物研究所标本馆(IBK)。岩生羊耳蒜与见血青(L.nervosa)在形态上相近,但前者叶银灰绿色,叶面平展,唇瓣基部胼胝体为短圆柱状突起,植株通常具珠芽而易与后者区分。岩生羊耳蒜居群内个体呈聚集式分布,并与其具有的珠芽繁殖方式相关。     

Rapid clonal propagation of Pinellia ternata by tissue culture

Adventitious buds or protocorm-like bodies were regenerated directly from excised explants without intervening callus. Differences in the ability of regeneration were observed among different plant organs with bulbils showing the highest regenerative ability followed by leaf blade and petiole. Ability of vegetative propagation of bulbil could be maintained by alternate solid-and liquid-medium culture. Theoretically, 1.7×10²⁷ plantlets could be produced from a single bulbil by this technique within one year based on the production and rapid growth of protocorm-like bodies and adventitious buds. Concentration of MS salts, NAA and sucrose influenced not only root formation from the differentiated adventitious buds, but also root number and length. For root formation, the best combination was one-half strength MS salts with 3–5% sucrose and 1 mg/l NAA. The high survival rate of 96% was recorded when plantlets were transplanted into a mixture of vermiculite:loam soil:peat moss (1:2:1). Plants from in vitro culture were morphological similar to field-grown plants. The acute toxicity of crude extracts from protocorm-like bodies was about one-fourth that of extracts from tubers of field-grown plants when tested with white mice. Tissue culture has potential for clonal propagation of Pinellia ternata plants for commercial use.Abbreviations MS Murashige and Skoog (1962) - 2,4-D 2,4-dichlorophenoxyacetic acid - NAA -naphthaleneacetic acid - BA 6-benzylaminopurine     

Life history and population dynamics of the Japanese Yam,Dioscorea japonica thunb.

Shoot morphology at the emergence ofDioscorea japonica Thumb. could be classed into the following three types: (1) a seedling emergence with only one leaf (Se type), (2) a plant consisting of one stem and one leaf, which has emerged from a small tuber (rhizophore) or bulbil less than 50 mg in dry weight (S type) and (3) a twiner with many leaves, which has emerged from a tuber or a bulbil of more than 50 mg in dry weight (L type). The Se type failed to develop beyond the second leaf stage in 1.5% sunlight exposure. The effects of initial plant (seeds, bulbils and tubers) size and light intensity on plant growth were analyzed. The larger the initial plant size was, the greater the growth in height and leaf area was. The distribution ratio of assimilated substances in leaves was high in smaller plants at the early growth stage. The distribution ratio in the tubers of larger plants became high at the early stage of growth. In all three types at over 3% sunlight exposure, the switch-over from the vegetative to reproductive growth phase occurred simultaneously at a later growth stage, but the Se type at 1.5% sunlight exposure showed a very early switch-over in its development; this switch-over may be related to shade tolerance capacity. The L type showed shade avoidance by forming a large productive structure as a twiner     

Hormones talking: Does hormonal cross-talk shape the Arabidopsis gynoecium?

The proper development of fruits is important for the sexual reproduction and propagation of many plant species. The fruit of Arabidopsis derives from the fertilized gynoecium, which initiates at the center of the flower and obtains its final shape, size, and functional tissues through progressive stages of development. Hormones, specially auxins, play important roles in gynoecium and fruit patterning. Cytokinins, which act as counterparts to auxins in other plant tissues, have been studied more in the context of ovule formation and parthenocarpy. We recently studied the role of cytokinins in gynoecium and fruit patterning and found that they have more than one role during gynoecium and fruit patterning. We also compared the cytokinin response localization to the auxin response localization in these organs, and studied the effects of spraying cytokinins in young flowers of an auxin response line. In this addendum, we discuss further the implications of the observed results in the knowledge about the relationship between cytokinins and auxins at the gynoecium.