The Hexagonal Branching Pattern of Rhizomes of Alpinia speciosa L. (Zingiberaceae)

Alpinia speciosa L. (Zingiberaceae) is a striking example ofa plant in which an organized architectural structure fulfilsa basic functional requirement - the economical explorationand exploitation of the substrate. This rhizomatous plant spreadslaterally in a predictable manner by vegetative growth to forma clone of separated ramets. A morphological study establishes‘rules of growth’ governing the success and failureof lateral branches (sympodial units), their lengths, and theirrelative angles. The basic branching pattern of this rhizome system approximatesto that of a hexagonal grid - the most economical structuralshape that uniformly ‘samples’ a plane surface.It is shown that the significant deviation of branching anglefound in Alpinia from that required to develop an exact hexagonalnetwork will virtually eliminate aerial shoot ‘clashes’in which the placing of one aerial shoot coincides with thatof another aerial shoot, whilst at the same time enhancing thebenefits of the hexagonal system. The broader implications ofthe organised architecture of plants are emphasised. rhizome, branching pattern, architecture, productivity     

箭秆风（姜科）的名实问题

箭秆风Alpinia jianganfeng T.L.Wu一名应为四川山姜A.sichuanensis Z.Y.Zhu的新异名。     

草豆蔻传粉生物学的研究

比较研究了花柱卷曲性植物草豆蔻 Alpinia hainanensis两种表型(上举型和下垂型)的传粉生物学特性。结果表明:草豆蔻的花柱卷曲运动节律与其他已报道的山姜属Alpinia植物基本一致,而下垂型花的花柱卷曲运动明显滞后于上举型花约2 h。草豆蔻的花柱卷曲运动中存在一些不同步的现象,甚至在同一花序上的两朵花的花柱运动节律亦会表现出不一致的现象,但上举型花的花药开裂时间却严格同步,都发生在同类型个体的柱头全部位于花药上方之后进行。草豆蔻上举型花的花蜜分泌量、单花花粉量、花粉/胚珠比率(P/O)均明显比下垂型花多,而两种表型的胚珠数、花蜜糖含量、氨基酸含量无显著差异。在草豆蔻的单花期内不同时间段进行人工授粉,上举型花在其柱头位于花药下方时进行人工授粉,其结实率明显比柱头位于花药上方时人工授粉的处理高,下垂型花则没有显著差异。在自然居群中,草豆蔻的主要传粉者是无垫蜂Ameglla sp.和两种木蜂Xylocopa sp.,但存在传粉者不足而影响结实率的现象。完全套袋、去雄和去雌(去柱头)处理的均不结实,表明草豆蔻中不存在无融合生殖、主动自花授粉和滞后自交的生殖保障现象。而人工自交和异交均具有较高的结实率,表明草豆蔻为自交亲和植物。草豆蔻的繁育系统是具花柱卷曲性运动的异花授粉的交配系统。     

Alpinia newmanii sp. nov. (Zingiberaceae) from central Vietnam

Alpinia newmanii, a new species from central Vietnam, is described and illustrated. A morphological comparison with the most closely related species and a key to the species of Alpinia subsection Catimbium in Vietnam are provided.     

Volatile essential oil constituents of Alpinia smithiae (Zingiberaceae)

The composition of leaf and rhizome essential oils of Alpinia smithiae that grow wild in the Western Ghats of Kerala (South India) was analysed by gas chromatography. The major components were beta-caryophyllene, sabinene, myrcene and 1,8-cineole in both samples, but variation in the yield of oil as well as the major components between the two plant parts was observed.     

Comparative leaf anatomy of Alpinia Roxb. species (Zingiberaceae) from China

The leaf anatomy of 20 Alpinia species from China was investigated. Results show that there is interspecific variation in the structure of the leaf midrib and petiole which can be used for species identification. Adaxial hypodermis is present in the lamina in all species of subgenus Catimbium and absent from all species of subgenera Dieramalpinia and Aobolocalyx and Alpinia , excepting A. conchigera, A. galanga and A. aquatica , which appear to be closely allied in having subepidermal fibres in midribs and petioles, which are absent from the rest of the species.     

The molecular phylogeny of Alpinia (Zingiberaceae): a complex and polyphyletic genus of gingers

Alpinia is the largest, most widespread, and most taxonomically complex genus in the Zingiberaceae with 230 species occurring throughout tropical and subtropical Asia. Species of Alpinia often predominate in the understory of forests, while others are important ornamentals and medicinals. Investigations of the evolutionary relationships of a subset of species of Alpinia using DNA sequence-based methods specifically test the monophyly of the genus and the validity of the previous classifications. Seventy-two species of Alpinia, 27 non-Alpinia species in the subfamily Alpinioideae, eight species in the subfamily Zingiberoideae, one species in the subfamily Tamijioideae, and three species in the outgroup genus Siphonochilus (Siphonochiloideae) were sequenced for the plastid matK region and the nuclear internal transcribed spacer (ITS) loci. Parsimony analyses of both individual and combined data sets identified six polyphyletic clades containing species of Alpinia distributed across the tribe Alpinieae. These results were supported by a Bayesian analysis of the combined data set. Except in a few specific cases, these monophyletic groupings of species do not correspond with either Schumann's (1904) or Smith's (1990) classification of the genus. Here we build on previous molecular analyses of the Alpinioideae and propose the next steps necessary to recognize new generic boundaries in the Alpinieae.     

Subcellular localization of calcium during Alpinia mutica Roxb. (Zingiberaceae) style movement

The subcellular localization of calcium in Alpinia mutica Roxb. during style movement was studied in two morphs. In the styles, Ca-antimonate precipitates (ppts) were principally located in apoplasts, with some minimal accumulation in the nucleus. At different movement, stages of movement, the ppts in the abaxial and adaxial sides changed, and no lateral gradient of ppts in the apoplast was established. The increase or decrease of ppts in the apoplast was not accompanied with equivalent changes in the cytoplasm. These results indicate that calcium could not affect the curvature by inhibiting cell elongation but may play a role in style movement by acting as a secondary messenger. EGTA-treatment affected style movement, providing further evidence supporting a role for calcium as a secondary messenger     

Comparative leaf anatomy of Alpinia species (Zingiberaceae) in Malaysia

The leaf anatomy of 22 Alpinia species from the Malay Peninsular was investigated. Results show that a combination of characters such as outlines of midribs, petioles, leaf margins and their relative sizes in transverse sections as well as the presence of hypodermal fibres in the lamina, midribs and petioles can be used in the identification of species. All four species of subsection Allughas possess similar characters such as the presence of abaxial and adaxial fibres in the midrib and petioles and the absence of hypodermis in the lamina while the reverse is true for all species of subsection Catimbium. Alpinia conchigera and A. galanga appear to be closely related while A. oxymitra is distinct from all the species studied.     

Adaptive significance of flexistyly in Alpinia blepharocalyx (Zingiberaceae): a hand-pollination experiment

BACKGROUND AND AIMS: Flexistyly is a sexual dimorphism where there are two morphs that differ in the temporal expression of sexual function and also involve reciprocal movement of the stigmatic surface through a vertical axis during the flowering period. The adaptive significance of flexistyly has been interpreted as a floral mechanism for outcrossing, but it may also function to reduce sexual interference in which styles and stigmas impede the pollen export. Here these two explanations of flexistyly were tested in Alpinia blepharocalyx through a hand-pollination experiment. METHODS: Hand-pollinations were performed in two temporal morphs and consisted of two sequential pollination treatments, namely self-pollination in the morning and inter-morph pollination in the afternoon (treatment 1) or conversely inter-morph pollination in the morning and self-pollination in the afternoon (treatment 2), and two simultaneous self- and inter-morph cross-pollination treatments either in the morning (treatment 3) or in the afternoon (treatment 4). Seed paternity was then determined to assess relative success of self- versus cross-pollen using allozyme markers. KEY RESULTS: In the sequential pollination treatments, whether the stigmas of recipients are receptive in the morning is crucial to the success of the pollen deposited. When the cataflexistylous (protandrous) morph served as pollen recipient, early-arriving pollen in the morning can sire only a very small proportion (<15%) of seeds because the stigmas were then unreceptive. However, when the anaflexistylous (protogynous) morph served as pollen recipient, early pollen did gain a large competitive advantage over the late pollen, particularly when cross-pollen arrived first. Simultaneous self- and inter-morph cross-pollination indicated that outcross-pollen is more competitive than self-pollen on receptive stigmas. CONCLUSIONS: Differential maturing of male and female organs in Alpinia blepharocalyx is sufficient for selfing avoidance, obviating the need for style movements. Instead, the upward style curvature of the cataflexistylous morph in the morning and the anaflexistylous morph in the afternoon most likely represents a means of reducing interference with pollen export.     

The Striped Squirrel (Tamiops swinhoei hainanus) as a Nectar Robber of Ginger (Alpinia kwangsiensisy)

Nectar robbing by squirrels is reported for the first time in the striped squirrel (Tamiops swinhoei hainanus), which was found robbing nectar from ginger plants (Alpinia kwangsiensis) in tropical forests of south Yunnan, China. We describe the behavior of squirrels visiting inflorescences, and we compare the fruit set of inflorescences visited by squirrels with that of inflorescences not subject to nectar robbing by squirrels. Most of the styles of robbed flowers were damaged and the affected plants exhibited reduced fruit set.     

Reproductive biology of Alpinia blepharocalyx (Zingiberaceae): another example of flexistyly

The floral biology and breeding system of Alpinia blepharocalyx were studied in Yunnan province, southwest China. Our results indicate that populations of A. blepharocalyx have two floral morphs, which differ in flowering behaviour: the cataflexistylous morph in which the stigma is held erect above the dehiscent anther when anthesis begins in the morning and becomes curved under the anther at afternoon, and the anaflexistylous morph in which the receptive stigma is curved under the indehiscent anther first and moves into a reflexed superior position above the anther as it begins to shed pollen in the afternoon; the flowering period of both floral morphs is 12 hours; the stylar movements in the two floral morphs are synchronous, and they have similar traits to those found in other Alpinia species previously reported. Also, on average, cataflexistylous flowers are larger than anaflexistylous flowers, especially the labellum and corolla tube length; moreover, the P/O ratio of the two floral morphs is significantly different: the cataflexistylous morph has more pollen grains and fewer ovules than the anaflexistylous morph; the evolutionary significance of this comparison is discussed. Cataflexistylous flowers were observed to produce a lower concentration of nectar than that of anaflexistylous flowers before 11:00 a.m., but they then have higher nectar concentration; cataflexistylous flowers always have more nectar than anaflexistylous flowers. Flowers of A. blepharocalyx were visited by fewer insects at a lower frequency, including honey bees (Apis cerana cerana) and two species of carpenter bees (Xylocopa spp.). No significant differences were found in the fruit set among the hand-pollination treatments regardless of selfing (geitonogamy and autogamy) or crossing (intermorph and intramorph); but all hand-pollination treatments exhibited much higher fruit set than the controls; meanwhile, no fruit set occurred in the unpollinated bagged plants. Pollen tube growth was examined using fluorescence microscopy following self, intramorph, and intermorph hand pollinations at different times of the day; the pollen tubes of both floral morphs have the same growth rate and the capability to reach the ovary. Both the results of pollen tube growth and fruit sets under different pollination conditions show that A. blepharocalyx is self-compatible and dependent upon insects for pollination. The distinctive flexistyly mechanism of A. blepharocalyx is likely a floral mechanism that promotes effective intermorph pollen transfer.     

Mating system and stigmatic behaviour during flowering of Alpinia kwangsiensis (Zingiberaceae)

 Little is known about the breeding systems of tropical perennial ginger species. In this paper, we provide information about the breeding system of Alpinia kwangsiensis in Yunnan, Southwest China, specifically self-compatibility, mechanisms promoting outcrossing, and the visitation characteristics of pollinators. Populations of A. kwangsiensis have two specific phenotypes that differ in flowering behaviour: 1) “cataflexistyle” individuals in which the stigma is held erect above the dehiscent anther when anthesis begins in the morning and becomes decurved under the anther at noon and 2) “anaflexistyle” individuals in which the receptive stigma is decurved under the indehiscent anther first and moves into a reflexed superior position above the anther as it begins to shed pollen at mid-day. The stigmatic movements in the two floral phenotypes, which occur in a ratio of 1:1 in natural populations, are synchronous and correlate with the foraging behaviour of floral visitors; pollination is effected only between floral forms. Field experiments indicate that A. kwangsiensis is self-compatible and dependent upon insects for fertilization. This newly reported floral mechanism, which we have named “flexistyly,” adds to the repertoire of devices that have evolved in flowering plants to insure outcrossing. Received November 29, 2001 Accepted January 8, 2002     

Floral and pollinator behaviour of flexistylous Bornean ginger, Alpinia nieuwenhuizii (Zingiberaceae)

Flexistyly is a unique floral mechanism involving extreme curving of the style. It was first described in Chinese ginger (Amomum, Zingiberaceae). This is a pioneer report on flexistylous gingers of Malesia, where most species of this family grow. We observed the floral behaviour and flower visitors in Alpinia nieuwenhuizii Val., a Bornean endemic. Although the floral behaviour and effective pollinators (carpenter bees, Xylocopa) were similar between the Bornean species and the previously reported flexistylous Alpinia, the pollinator behaviour between them strikingly differed with regard to the visit frequency of the pollinators showing a bimodal pattern during the day. This was a better match for the floral behaviour of the flexistylous Alpinia. Some gender differentiation observed between the two types of morphs is also discussed in the present study.     

DPPH free radical scavenger components from the fruits of Alpinia rafflesiana Wall. ex. Bak. (Zingiberaceae)

The methanol extract of the dried ripe fruits of Alpinia rafflesiana was investigated for its DPPH free radical scavenger constituents. 2',3',4',6'-Tetrahydroxychalcone (7), which has never been isolated from natural sources was found to be most active as a DPPH free radical scavenger with the IC50 value of 55 microM. Other known compounds isolated from this species include 5,6-dehydrokawain (1), flavokawin B (2). 1,7-diphenyl-5-hydroxy-6-hepten-3-one (3), (-)-pinocembrin (4), cardamonin (5) and (-)-pinostrobin (6). The DPPH free radical scavenger compounds were detected using TLC autographic analysis. The percentage inhibition of DPPH free radical scavenging activity was measured on isolates (5-7) using colorimetric analysis.     

Chemical Diversity in the Genus Alpinia (Zingiberaceae): Comparative Composition of Four Alpinia Species Grown in Northern India

The essential‐oil compositions of leaves, flowers, and rhizomes of Alpinia galanga (L.) Willd ., Alpinia calcarata Rosc ., Alpinia speciosa K. Schum. , and Alpinia allughas Rosc . were examined and compared by capillary GC and GC/MS. Monoterpenoids were the major oil constituents identified. 1,8‐Cineole, α‐terpineol, (E)‐methyl cinnamate, camphor, terpinen‐4‐ol, and α‐ and β‐pinenes were the major constituents commonly distributed in leaf and flower essential oils. The presence of endo‐fenchyl acetate, exo‐fenchyl acetate, and endo‐fenchol was the unique feature of rhizome essential oils of A. galanga, A. calcarata, and A. speciosa. On contrary, the rhizome oil of A. allughas was dominated by β‐pinene. Significant qualitative and quantitative variations were observed in essential‐oil compositions of different parts of Alpinia species growing in subtemperate and subtropical regions of Northern India. Cluster analysis was performed to find similarities and differences in essential‐oil compositions based on representative molecular skeletons. Monoterpenoids, viz., 1,8‐cineole, terpinen‐4‐ol, camphor, pinenes, (E)‐methyl cinnamate, and fenchyl derivatives, were used as chemotaxonomic markers.     

Impact of Striped-Squirrel Nectar-Robbing Behaviour on Gender Fitness in Alpinia roxburghii Sweet (Zingiberaceae)

Nectar-robbing has the potential to strongly affect male and female reproductive fitness of plants. One example of nectar theft is that shown by striped-squirrels (Tamiops swinhoei) on a number of ginger species, including Alpinia roxburghii and A. kwangsiensis (Zingiberaceae). In this study, we used a fluorescent dye as a pollen analogue, and measured fruit and seed output, to test the effect of squirrel nectar-robbing on A. roxburghii reproductive fitness. Pollen transfer between robbed and unrobbed flowers was assessed by comparing 60 randomly established plots containing robbed and unrobbed flowers. The frequency of squirrel robbing visits and broken styles were recorded from a number of flowers for five consecutive days. Two bee species (Bombus eximius and Apis cerana), were the primary pollinators, and their visitation frequency was recorded for six consecutive days. The results showed that fluorescent powder from unrobbed flowers was dispersed further, and to a greater number of flowers than that placed on robbed flowers. Additionally, robbing flowers caused significant damage to reproductive organs, resulting in lower fruit and seed sets in robbed than in unrobbed flowers and influencing both male and female fitness. The frequency of the primary pollinator visits (B. eximius) was significantly higher for unrobbed plants than for robbed plants. The present study clearly shows the negative impact of squirrel robbing on A. roxburghii male reproductive fitness and neutral impact on female reproductive fitness.