青藏高原东缘不同海拔波缘风毛菊资源分配及花部特征对种子数目和质量的影响

通过采样调查法和烘干称量法检测了青藏高原东缘不同海拔种群波缘风毛菊(Saussurea undulata)花期与果期的形态特征, 研究了其花期与果期的资源分配, 并对花期花部特征对果期种子特征的影响作出分析。结果表明: 1)波缘风毛菊在花期将更多的资源投入繁殖器官, 而在果期增加了对种子的资源投资; 2)波缘风毛菊花期部分花部特征的变异导致其果期产生的种子随海拔升高数量减少、百粒重增加, 因为波缘风毛菊需要在高寒草甸的极端环境下保证每粒种子的存活能力, 因此采取了产生更少但更大种子的生存策略。     

Variability in reproductive traits in Jatropha curcas L. accessions during early developmental stages under warm subtropical conditions

Variability in floral, fruit, and seed characteristics, and oil content of 15 accession of Jatropha curcas during early development were assessed during two flowering periods in south Florida subtropical climate. The two flowering periods had leaf flushing in March. Field evaluation using 18 quantitative traits showed significant variation among accessions. The number of female flowers and female : male flower ratio ranged from 1 to 15 and 1 : 8.8 to 1 : 67.8, respectively. Fruit set by natural pollination was 89 and 66% during the first (1st) and second (2nd) flowering periods, respectively. A higher number of female‐type inflorescences were observed during summer. There were significant differences in seed traits, except for number of seeds per fruit. Accession TREC 31 had the highest individual seed dry weight and 100‐seed weight (0.83 g and 79.7 g, respectively). The oil content varied from 19.30% to 35.62%. Seed dry weight had positive correlation with seed fresh weight, seed length, seed thickness, seed width, and 100‐seed weight, but negative correlation with oil content. Based on the cluster analysis using 15 morphological traits, jatropha accessions were grouped into five main clusters and accessions from different geographic regions grouped together in a cluster. Principal component analyses (PCA) revealed morphological variation. The first three components explained 73.5% of the total variation and seed dry weight, 100‐seed weight, total flowers per inflorescence, male flowers per inflorescence and fruit set can be used to distinguish accessions. The PCA also indicated that flowering traits were more influenced by seed origin while seed traits were affected by flowering spans. Although evaluations were performed in plants during the juvenile phase, accessions TREC 31 and TREC 55 had superior averages for almost all characters evaluated. These results provide a preliminary assessment of the high variability in jatropha accessions evaluated and their potential for use in breeding and genetic improvement programs.     

Generation and characterization of SCARs by cloning and sequencing of RAPD products: a strategy for species-specific marker development in bamboo

BACKGROUND AND AIMS: The aim of this study was to develop species-specific molecular markers for Bambusa balcooa and B. tulda to allow for their proper identification, in order to avoid unintentional adulteration that affects the quality and quantity of paper pulp production. METHODS: Two putative, species-specific RAPD markers, Bb836 for B. balcooa and Bt609 for B. tulda were generated using a PCR-based RAPD technique. Species-specificity of these two markers was confirmed through Southern hybridization in which RAPD gels were blotted and hybridized with radiolabelled cloned RAPD markers. Southern hybridization analyses were also performed to validate homology of the co-migrating Bb836 and Bt609 marker bands amplified from 16 different populations of B. balcooa and B. tulda, respectively. Sequence-characterized amplified region (SCAR) markers were developed from Bb836 and Bt609 sequences, using 20-mer oligonucleotide primers designed from both the flanking ends of the respective RAPD primers. KEY RESULTS: As anticipated, Bb836 hybridized with an amplified band from B. balcooa and Bt609 hybridized only with an amplified product from B. tulda; the two markers did not hybridize with the amplified products of any of the other 14 bamboo species studied. The two pairs of SCAR primers amplified the target sequences only in the respective species. The species-specific SCAR fragments were named as 'Balco836' for B. balcooa and 'Tuldo609' for B. tulda. The species-specific 'Balco836' was amplified from the genomic DNA of 80 individuals of 16 populations of B. balcooa studied. Similarly, the presence of 'Tuldo609' was noted in all the 80 individuals representing 16 populations of B. tulda assessed. These SCAR fragments contained no obvious repetitive sequence beyond the primers. CONCLUSION: These two molecular markers are potentially useful for regulatory agencies to establish sovereign rights of the germplasms of B. balcooa and B. tulda. In addition, this is the first report of species-specific SCAR marker development in bamboo.     

Functional associations of floret and inflorescence traits among grass species

The aerodynamics of wind pollination selects for an intimate relation between form and function in anemophilous plants. Inflorescence architecture and floral morphology vary extensively within the Poaceae, but the functional implication of this variation remains largely unknown. Here we quantify associations between floret, culm, and inflorescence characteristics for 25 grass species in Kananaskis, Alberta, Canada, and consider whether different architectures may implement unique mechanisms to aid pollination. The species cluster into four categories defined by all combinations of floret size (small vs. large) and inflorescence architecture (compact vs. diffuse). Species differed significantly for all 18 traits that we measured, with 12 traits differing only between floret-size classes, three differing only between inflorescence types, and three differing among both (independently or by an interaction). Based on these morphological associations, we discuss the aerodynamic and functional consequences of each category for wind pollination. The independence of inflorescence and floral traits has probably allowed exploration of all possible combinations of inflorescence architecture and floret size during the evolution of the Poaceae.     

紫距淫羊藿的形态变异式样及描述修订

紫距淫羊藿为根据少量栽培个体描述的中国特有种,狭域分布于湖南省天平山,自发表以来未见后续形态学研究。为了掌握紫距淫羊藿形态变异式样并为该物种及其近缘种的分类提供依据,该研究在模式产地湖南省桑植县天平山,于花果期开展野外居群的形态观测,对紫距淫羊藿主要性状进行变异分析以及形态描述的完善或修订,并提供了该物种的形态图片资料。结果表明:基于野外观测,紫距淫羊藿主要形态性状的变异范围均远超出物种发表原始文献的描述,如株高12.0～68.0 cm,大幅度高于原始描述的12cm;居群内结节状根茎和细长根茎并存,且两种类型的个体数量相当;其余性状,如叶长、叶宽、花序轴长、花色等都呈现丰富变异。此外,还补充描述了紫距淫羊藿的果实和种子的性状,蓇葖果长8～13 mm,内含种子2～11粒,种子具油质体。因此,分类学描述应重视野外观察,特别要注意个体间的变异并进行性状分析,这是分类研究的基础。     

Floral development in the tribe Cedreleae (Meliaceae, sub-family Swietenioideae): Cedrela and Toona

BACKGROUND AND AIMS: Floral development of Cedrela and Toona, the genera comprising the basal tribe Cedreleae of the sub-family Swietenioideae of Meliaceae, is described. The focus was on three endangered, ecologically and economically important species: Cedrela fissilis, Cedrela odorata and Toona ciliata. The aims of the study were to characterize the patterns of floral development in the tribe and to establish apomorphic and plesiomorphic floral characters in relation to other taxa within the family based on the current molecular phylogeny of Meliaceae. METHODS: A detailed floral structural and developmental study was completed using both scanning electron microscopy and visualization of microtome sections with a light microscope. KEY RESULTS: Twelve floral developmental stages were identified. The initial development of the pentamerous flowers of both Toona and Cedrela is strikingly similar. The morphological differences observed between them are due to differential patterns of organ elongation and adnation/connation occurring late in development. Additionally, the formation of functionally male and female flowers was found to occur at specific positions within the inflorescence. CONCLUSIONS: Due to the basal position of the tribe Cedreleae in the phylogeny of Meliaceae, functionally either male or female pentamerous flowers and the presence of (at least partially) free stamens may be considered plesiomorphic traits within the family. In contrast, sympetaly and the absence of nectaries in Cedrela species are synapomorphies.     

Diversity and evolution of pollinator rewards and protection by <Emphasis Type="Italic">Macaranga</Emphasis> (Euphorbiaceae) bracteoles

Flowering plants have modified their floral organs in remarkably diverse ways to optimize their interaction with pollinators. Although floral organs represent a major source of floral diversity, many plants also use extrafloral organs, such as bracts and bracteoles, in interacting with pollinators; however, the evolutionary dynamics of non-floral organs involved in pollination are poorly studied. The genus Macaranga is characterized by protective mutualisms with ants that potentially interfere with pollinators on flowers. Macaranga flowers lack perianths and, notably, bracteoles serve the dual function of rewarding pollinators and protecting them from guarding ants; in one group of species, bracteoles provide a nectar reward to generalist pollinators, while in another group, bracteole “chambers” protect thrips or hemipteran pollinators that use these structures as feeding and breeding sites. We examined the diversity and evolutionary dynamics of inflorescence morphology in Macaranga, focusing on bracteoles. We recognized three inflorescence types based on examination of herbarium materials: Discoid-gland, which possess disc-shaped glands on the bracteole surfaces (including all the generalist-pollinated species); Enclosing, in which bracteoles cover flowers (including all the thrips- and hemipteran-pollinated species); and Inconspicuous, in which bracteoles are small, narrow or absent. Ancestral state reconstruction indicated that inflorescence morphologies have changed multiple times in the genus. These findings suggest that morphological changes in non-floral characters (bracteoles) of Macaranga species have occurred as frequently as in the floral structures of many flowering plants. The multiple evolutions of the Enclosing bracteoles, which protect pollinators, might have been facilitated by pollination interference from mutualistic ants.     

A Developmental Pattern of Flowering in Colored <Emphasis Type="Italic">Zantedeschia</Emphasis> spp.: Effects of Bud Position and Gibberellin

The restricted flowering of colored cultivars ofZantedeschia is a consequence of developmental constraints imposed by apical dominance of the primary bud on secondary buds in the tuber, and by the sympodial growth of individual shoots. GA₃ enhances flowering inZantedeschia by increasing the number of flowering shoots per tuber and inflorescences per shoot. The effects of gibberellin on the pattern of flowering and on the developmental fate of differentiated inflorescences along the tuber axis and individual shoot axes were studied in GA₃ and Uniconazole-treated tubers. Inflorescence primordia and fully developed (emerged) floral stems produced during tuber storage and the plant growth period were recorded. Days to flowering, percent of flowering shoots and floral stem length decreased basipetally along the shoot and tuber axes. GA₃ prolonged the flowering period and increased both the number of flowering shoots per tuber and the differentiated inflorescences per shoot. Activated buds were GA₃ responsive regardless of meristem size or age. Uniconazole did not inhibit inflorescence differentiation but inhibited floral stem elongation. The results suggest that GA₃ has a dual action in the flowering process: induction of inflorescence differentiation and promotion of floral stem elongation. The flowering pattern could be a result of a gradient in the distribution of endogenous factors involved in inflorescence differentialtion (possibly GAs) and in floral stem growth. This gradient along the tuber and shoot axes is probably controlled by apical dominance of the primary bud. Online publication: 7 April 2005     

Between-year changes in functional gender expression of Palicourea padifolia (Rubiaceae), a distylous, hummingbird-pollinated shrub

BACKGROUND AND AIMS: Because distylous species have two hermaphroditic style-length floral morphs, they face two sex allocation problems: the equilibrium morph ratio and the optimal allocation to pollen and seed production in each floral morph. Gender specialization is expected among distylous species when floral morphs differ in reproductive output. However, spatio-temporal variability in female reproductive output between morphs needs to be investigated to fully understand patterns of sexual expression and gender specialization in distylous plants. Between-year variation in flower and fruit production of hummingbird-pollinated Palicourea padifolia (Rubiaceae) was examined, focusing on functional gender expression of long- and short-styled morphs and comparing their reproductive performance in five consecutive years (1998-2002). METHODS: Between-year variation in inflorescence, floral bud and fruit production was monitored and quantified. These traits were then used as parameters to determine functional gender differences between floral morphs through time. KEY RESULTS: Inflorescence production varied among years but no significant differences were found between floral morphs. Long-styled plants initiated more floral buds per inflorescence every year than short-styled plants, suggesting higher allocation to pollinator attraction and, potentially, an increase in male fitness through pollen donation. Although fruit production was similar between morphs, their functional gender shifted across years. CONCLUSIONS: The gender expression inconsistency across years is surprising because a number of floral characters and attributes that contribute to differently attracting and rewarding effective pollinators in P. padifolia suggest gender specialization. The evidence that morphs of distylous species might specialize in functional gender mostly comes from differences among populations in seed production and non-equilibrium morph ratios based on 1-year field population surveys. The results suggest that more sampling through time is needed to detect gender specialization among distylous species with a perennial habit.     

Seasonal pollen flow and progeny diversity in Amianthium muscaetoxicum: ecological potential for multiple mating in a self-incompatible,hermaphroditic perennial

Summary The ecological potential for multiple mating is high in Amianthium muscaetoxicum. The percentage of long-distance pollinations (20–100 m) is greater than reported for most insect-pollinated systems. Estimations of neighborhood area are at least an order of magnitude larger than any previously reported for plant species. Seasonal effects on fluorescent dust dispersal indicate that neighborhood areas change during the flowering season. The number of flowers marked with fluorescent dust on an inflorescence increases with increasing inflorescence size, and the proportions of available inflorescences that are marked decrease with distance from the source. Allozyme analysis indicates that heterozygosity levels are typical of outcrossing plants. The diversity of seed genotypes is increased by increasing the size of the floral display. The present investigation is the first to consider the effects of floral display on seed diversity and adds to existing data indicating that inflorescence size is important to fecundity and/or pollen donation in some systems.     

关苍术花部综合特征与繁育系统的研究

采用定点观察,运用杂交指数估算、花粉/胚珠比(P/O)测定、套袋授粉等方法,对关苍术的花部综合特征及繁育系统进行研究。结果表明:种群花期为7月下旬至9月初,单花序花期为12~17 d,小花日开放高峰期为早上7:00~8:00;花粉活力最高(90%以上)在开花后2 h以内,而此时其柱头尚无可授性,柱头在花开48~72 h以内具有较强可授性;花粉/胚珠比为6 690,杂交指数为5,繁育系统为专性异交,优势访花者为蜂类和蝇类;套袋和授粉实验结果表明关苍术不存在无融合生殖现象,自交和同株异花结实率很低,其繁育系统以异交为主。通过关苍术花部综合特征和繁育系统的研究,进一步了解其生物学特性,为关苍术资源保护和人工培育提供了理论基础。     

斗竹的开花生物学特性研究

通过野外观测及光学解剖,观察了斗竹(Oligostachyum spongiosum)开花林相、开花动态、花器官构造、结实情况,以及花后林相更新等生物学特性,采用光学显微技术结合石蜡制片,对斗竹的大、小孢子的发生及雌、雄配子体的发育过程进行研究。结果表明：(1)斗竹为一次性整体开花竹类,花期为4月下旬～5月下旬,花期约持续45 d,成花量大。(2)花序为圆锥状混合花序,每花序由4枚小穗构成;小穗细长,每枚小穗由5～17枚小花组成;小花为颖花,顶部小花不发育,外稃、内稃各1枚;浆片3枚,卵圆形;雄蕊4～6枚(多为6),每枚花药具有4个花粉囊,花药壁发育为基本型,绒毡层为腺质型,小孢子四分体为左右对称型,成熟花粉粒为2 细胞型,球形,表面纹饰颗粒状,具单个萌发孔,花粉发育过程中部分花药出现异常收缩及空腔的败育花粉粒;雌蕊1枚,柱头3叉,羽毛状,子房1室,胚珠倒生,厚珠心,胚囊为蓼型,成熟胚囊结构及发育过程均正常;雌雄同熟,异花授粉,果实为颖果。(3)斗竹花后全林死亡,结实率低,自然条件下结实率为8.1%。研究结果为研究竹子系统分类、开花机制,开展杂交育种及竹林更新复壮工作等提供基础性资料。     

Phenological regulation of opportunities for within-inflorescence geitonogamy in the clonal species,iris versicolor (iridaceae)

Opportunities for selfing through geitonogamy are possible if more than one flower within the same clone, inflorescence, or floral unit is open at the same time. In a total of 200 inflorescences in two natural populations of Iris versicolor, flowers were observed and classified daily on the basis of anther dehiscence and stigma receptivity. Analysis of the flowering phenology demonstrated that (1) protandry limits opportunities for autogamy, (2) flowers mature sequentially within a floral unit (defined as a cluster of flowers borne on a single branch within an inflorescence), preventing the opportunity for geitonogamous fertilization between flowers of the same floral unit, and (3) 77% of all flowers had no opportunity to be pollinated by another flower within the same inflorescence. Both the number and the proportion of flowers with opportunities for geitonogamy increased with the number of flowers open in each population, and opportunities for geitonogamy also increased with the number of floral units within inflorescences. These morphological and phenological controls suggest that when selfing occurs in this species, it is most likely to occur between flowers on different inflorescences within the same clone. Since the organization of whole inflorescences in space is determined primarily by rhizome placement, clonal architecture may play an important role in mating system regulation in this species.     

Biosystematic Studies on Adenophora potaninii Korsh. Complex (Campanulaceae). Ⅰ. Phenotypic Plasticity

Phenotypic plasticity is the environmental modification of genotypic expression and an important means by which individual plants respond to environmental heterogeneity. The study of phenotypic plasticity in the genus Adenophora, which is very complicated taxo nomically because of great morphological variation, proves to be helpful in both investigating the phenotypic variation so as to evaluate potential taxonomic value of their characters and providing important sources of information on the variation, adaptation and evolution of the genus. Twenty-three populations representing all the six species in Adenophora potaninii complex were transplanted into the garden. Of them six populations were selected for study ing their performance in the field and in the garden, in addition to cultivation experiment under different treatments. The results show that there exists considerable developmental plasticity in some leaf, floral and capsule characters. In particular, the leaf shape and length of calyx lobe display significant developmental variation with the maximum being three times as great as the minimum, which is noteworthy because they were previously considered as diagnostic. The characters of root, caudex, stem and inflorescence are found to be very plastic, especially the root diameter, the number of stems, stem height and inflorescence length with great environmental plasticity. In addition, the populations from different habi tats show distinct amounts of plasticity. On the contrary, the characters of leaf, floral, cap sule and seed are less influenced by environments. It seems that the considerable variation in the characters of leaf is attributed mainly to genetic differences. Finally, the phenotypic plasticity of morphological characters of A. potaninii complex and its taxonomic significanceis discussed.     

Genetic interactions in the control of flowering time and reproductive structure development in tomato (Solanum lycopersicum)

Different tomato (Solanum lycopersicum) mutants, affected in flowering time, reproductive structure or plant architecture, were crossed to produce double mutants in order to investigate gene interactions in flowering regulation in this autonomous species with a sympodial growth habit. The compound inflorescence: uniflora, uniflora: self pruning, uniflora: blind, and jointless: uniflora double mutants all produced solitary flowers like their uniflora parent, instead of inflorescences. All double mutants were late flowering. uniflora: blind and uniflora: self pruning had flowering times intermediate between those of their two parents. jointless: uniflora and compound inflorescence: uniflora flowered later than uniflora, the mutant with the most delayed flowering. All double mutants developed strong lateral shoots at node levels approximately corresponding to the level at which their parent cultivars initiated their first reproductive structure, which is a typical trait of uniflora. These results suggest that the UNIFLORA gene acts upstream of the other investigated genes in controlling flowering in tomato, and that floral transition of the primary shoot and floral transition of sympodial segments are regulated differently.     

十齿花属分类地位的研究

本文对过去认为与十齿花属近缘的科,属的形态,木材解剖,花粉形态等方面的特征进行了较全面的比较研究。结果支持最初作者置于卫矛科的意见,并建立十齿花亚科,置于卫矛亚科和雷公藤亚科之间。滇西北产者订为一所种。     

Phylogeny of the basal angiosperm genus Pseuduvaria (Annonaceae) inferred from five chloroplast DNA regions, with interpretation of morphological character evolution

Phylogenetic relationships within the magnoliid basal angiosperm genus Pseuduvaria (Annonaceae) are investigated using chloroplast DNA sequences from five regions: psbA-trnH spacer, trnL-F, matK, rbcL, and atpB-rbcL spacer. Over 4000 nucleotides from 51 species (of the total 53) were sequenced. The five cpDNA datasets were analyzed separately and in combination using maximum parsimony (MP), maximum likelihood (ML), and Bayesian methods. The phylogenetic trees constructed using all three phylogenetic methods, based on the combined data, strongly support the monophyly of Pseuduvaria following the inclusion of Craibella phuyensis. The trees generated using MP were less well resolved, but relationships are similar to those obtained using the other methods. ML and Bayesian analyses recovered trees with short branch lengths, showing five main clades. This study highlights the evolutionary changes in seven selected morphological characters (floral sex, stamen and carpel numbers, inner petal color, presence of inner petal glands, flowering peduncle length, and monocarp size). Although floral unisexuality is ancestral within the genus, several evolutionary lineages reveal reversal to bisexuality. Other phylogenetic transitions include the evolution of sapromyophily, and fruit-bat frugivory and seed dispersal, thus allowing a wide range of adaptations for species survival.     

濒危药用植物云南黄连传粉生态学研究

云南黄连为中药材黄连的原植物之一,为国家二级濒危保护植物。通过对云南黄连的开花物候、花部特征、繁育系统及传粉方式进行观察研究,以探讨云南黄连濒危机制,为其种质资源保护及人工抚育奠定基础。结果表明:(1)云南黄连的花期从12月份起至第二年的3月份,花期长达4个月,花序开花可持续45～60d,同一花序上不同花的开花时间相隔1～3d,单花花期可持续40～45d。(2)云南黄连为多歧聚伞花序,苞片包被花芽,花两性,雄蕊和心皮多数。(3)云南黄连的花粉-胚珠比(P/O)为9 000左右,杂交指数(OCI)值为4或5,为自交亲和但需要传粉者完成传粉的兼性异交型繁育系统,并存在无融合生殖现象。     

Seed mix design and first year management influence multifunctionality and cost‐effectiveness in prairie reconstruction

Agricultural intensification continues to diminish many ecosystem services in the North American Corn Belt. Conservation programs may be able to combat these losses more efficiently by developing initiatives that attempt to balance multiple ecological benefits. In this study, we examine how seed mix design and first year management influence three ecosystem services commonly provided by tallgrass prairie reconstructions (erosion control, weed resistance, and pollinator resources). We established research plots with three seed mixes, with and without first year mowing. The grass‐dominated “Economy” mix had 21 species and a 3:1 grass‐to‐forb seeding ratio. The forb‐dominated “Pollinator” mix had 38 species and a 1:3 grass‐to‐forb seeding ratio. The grass:forb balanced “Diversity” mix, which was designed to resemble regional prairie remnants, had 71 species and a 1:1 grass‐to‐forb ratio. To assess ecosystem services, we measured native stem density, cover, inflorescence production, and floral richness from 2015 to 2018. The Economy mix had high native cover and stem density, but produced few inflorescences and had low floral richness. The Pollinator mix had high inflorescence production and floral richness, but also had high bare ground and weed cover. The Diversity mix had high inflorescence production and floral richness (comparable to the Pollinator mix) and high native cover and stem density (comparable to the Economy mix). First year mowing accelerated native plant establishment and inflorescence production, enhancing the provisioning of ecosystem services during the early stages of a reconstruction. Our results indicate that prairie reconstructions with thoughtfully designed seed mixes can effectively address multiple conservation challenges.