荨麻科楼梯草属三种植物花序的补充描述

楼梯草属的花序不但是反映该属进化趋势的重要器官之一,而且还是该属的属下划分及种间鉴定的关键性状。本文基于大量的有花标本研究,并参照模式标本及相关文献资料对该属的三种植物花序形态进行了补充描述。     

竹亚科箭竹属两种植物花序的补充描述

根据所看到和采集到的标本对竹亚科箭竹属两种植物云龙箭竹和元江箭竹的花序特征做了较为详细的中文以及拉丁文补充描述。该文对箭竹属的分类提供了更丰富的参考凭证,对今后该属的修订工作有较大的意义。     

倭竹族花序演化的探讨

倭竹族隶于禾本科之竹亚科。本族计有10属约150余种。分布于东南亚季风带的印度、越南、中国及日本等国,我国产8属约120种,占该族全部属种的80％。其中唐竹属、短穗竹属、筇竹属、八月竹属等均为我国所特产,唐竹属1种早期引入日本栽培,倭竹属、大节竹属、方竹属、刚竹属等也主要分布于我国,只有少数种分布于其它国家,业平竹属和阴阳竹属为日本特产。 刚竹属计有70种之多,我国产50种以上,是本族中种类最多的属,其中有许多种类分布广、适应能力强,用途多、产量大。是重要的植物资源.尤其是毛竹,是我国亚热带地区的主要栽培竹种。 倭竹族花序演化的研究对于进一步认识和鉴别竹类植物.了解竹类植物的演化关系。使竹类植物的系统安排更加合理都是有益的。倭竹族的花序属于假花序.与真花序相比较属于原始类型。本族中花序轴反复分枝.具有极多小穗的短穗竹属,业平竹属等是比较原始的,大节竹属、唐竹属的花序简化、花序轴不分枝或仅有少数分枝,含小穗数很少是进化类型。     

中国鹿角兰属(兰科)植物新资料

报道了中国兰科(Orchidaceae)鹿角兰属(Pomatocalpa)一新记录种——纹瓣鹿角兰［P. tonkinense (Gagnep.) Seidenf.］,凭证标本保存于广西植物研究所标本馆(IBK)。纹瓣鹿角兰的花序疏生多数花,萼片、花瓣均具2条紫色条纹,中萼片及花瓣远长于侧萼片,与中国原记录的2种鹿角属植物容易区分。该研究提供了新记录种的形态描述、中国鹿角兰属植物图版及分种检索表。     

中国花楸属单叶类群叶脉序特征研究

中国花楸属单叶类群(24种)包含落萼组与冠萼组,亦有学者将其分为两个属(白花楸属和水榆属)或合并成为一个属(白花楸属).由于其花序和果实的高度相似性,长期以来分类地位具有争议,而叶脉序特征在花楸属单叶类群中的分类作用尚不明确.因此,该研究以国产花楸属落萼组的13个物种和冠萼组的7个物种作为研究对象,以清净法制作标本对叶...     

Q型聚类分析在东北水生植物香蒲属分类研究中的应用

香蒲属（Typha）植物是我国东北水生植物中的重要类群,作者首次利用数值分类学中的Q型聚类分析方法对东北产香蒲属七种植物进行分析,可望为科学地研究该类群提供依据,同时也对传统分类进行评价。l材料与方法以香蒲属这7个种（表1）作为分类运算单位（OperahonaltaxonoAnc。L简称OTU）,主要观察和测量了7种植物的营养体、花序、花期及花粉等性状,首先对其性状数据化,并对该原始数据进行标准差标准化处理,共筛选出50个性状的原始数据（表对,对其进行数量分类。特征记录主要靠观察和测量植物标本、腊叶标本及花粉形态数据等,其性…     

四种刚竹属植物花器官形态描述

该文根据采自华东地区的一些刚竹属植物居群中的可靠花枝标本,结合现场调查和形态解剖观察,描述和增补了白哺鸡竹、瓜水竹、谷雨竹、云和哺鸡竹的花序、假小穗和花部形态特征,并提供了显示花枝外貌和花器官主要特征的照片。瓜水竹的花序呈头序,小花较短,应属于水竹组;而其余3种的花序呈穗状,小花较长,应归隶刚竹组。所有的凭证标本均保存于安徽省广德县林业科学研究所竹类标本室中。     

四种刚竹属植物花器官形态描述（英文）

该文根据采自华东地区的一些刚竹属植物居群中的可靠花枝标本,结合现场调查和形态解剖观察,描述和增补了白哺鸡竹、瓜水竹、谷雨竹、云和哺鸡竹的花序、假小穗和花部形态特征,并提供了显示花枝外貌和花器官主要特征的照片。瓜水竹的花序呈头序,小花较短,应属于水竹组;而其余3种的花序呈穗状,小花较长,应归隶刚竹组。所有的凭证标本均保存于安徽省广德县林业科学研究所竹类标本室中。     

重庆荨麻科一新种——缙云赤车

在重庆市北碚区缙云山野外植物调查过程中,于海拔500～800 m的溪边阴湿沟谷中发现一种荨麻科植物,虽然该物种雌花序具花序托,但因其雌花花被片5枚,外面先端具角状突起,瘦果只具瘤状突起,更符合赤车属的特征,且结合分子系统学证据,该物种明显属于赤车属.该物种的特征在于其具花序托和总苞的雌花序,根据这一特征可将其置于头序赤...     

湖南葡萄科植物小志

本文描述湖南葡萄属2新种,葡萄科该省新记录2种,1变种,并根据花序着生位置、花构造等特征,确认粉叶爬山虎仍系属于爬山虎属的植物。最近中南林学院林学系寄作者一批葡萄科标本,其中有2新种,以及新分布等,现在本文发表。     

The consequences of rewardlessness in orchids: reward-supplementation experiments with Anacamptis morio (Orchidaceae)

Pollinators are expected to respond to low reward availability in an inflorescence by visiting fewer flowers before departure, thus potentially causing reduced visitation, but also reduced geitonogamous selfing. I tested this hypothesis using Anacamptis morio, an orchid that does not reward its pollinators. Supplementation of inflorescences with artificial nectar did not result in an increase in fruit set on supplemented inflorescences compared to control inflorescences and tended to reduce pollinia removal. Supplementation resulted in reduced fruit quality, but there was no evidence that this was as a result of inbreeding depression. Behavioral experiments showed that pollinating bumble bees, as predicted, visited more flowers on supplemented inflorescences. Bumble bees also deposited more self-pollen on supplemented inflorescences, but this was marginally significant. Bumble bee queens removed significantly more pollinia from control inflorescences, while Bombus terrestris and B. lucorum workers did not. I conclude that while pollinators behaved as predicted, there was weak evidence that pollinia removal, pollen deposition, and fruit set followed the predictions of the hypothesis. I argue that this was probably because some pollinators were more efficient at removing and depositing pollen on control inflorescences, while others were not.     

Vegetative Proliferation and Secondary Proliferated Inflorescences Development in Grass

We report the vegetative proliferation and new phenomenon of “secondary proliferated inflorescences” in the grass Ischaemum barbatum Retz, as determined by anatomical analysis of prepared sections of inflorescences. Leaves and shoots could be developed from the original spikelets of inflorescences and plantlets developed when these shoots were transplanted to moist soil. “Secondary proliferated inflorescences” is the first name here because some inflorescences that developed inadequacy are grown from the spikelet on the mother inflorescence. Our investigation showed that this form of vegetative proliferation and secondary proliferated inflorescences development of I. barbatum has arisen following late autumn fires of the previous year. It is suggested that the sudden onset of a fire could lead to a hormone imbalance or a chemical induction, which results in ephemeral vegetative proliferation even secondary proliferated inflorescences development in wild populations.(Author for correspondence. Tel: +86 (0)20 3725 2993; E-mail: magh@scib.ac.cn)     

The mating consequences of sexual segregation within inflorescences of flowering plants

Many co-sexual plants segregate female and male function among flowers on an inflorescence through dichogamy or the production of unisexual flowers. Sexual segregation may reduce self-pollination among flowers within inflorescences (geitonogamy), thereby increasing the pollen available for export to other plants. To assess these complementary roles we manipulated the simultaneously hermaphroditic (adichogamous) flowers of Eichhornia paniculata to produce ten-flowered inflorescences with either female above male flowers (female/male inflorescences) or male/female inflorescences, which competed for mating opportunities with five-flowered adichogamous inflorescences. Because of the upward movement of bumble-bees, selfing increased upward in adichogamous inflorescences (overall female selfing rate s+/-s.e.=0.320+/-0.026). Female flowers of male/female inflorescences selfed less than flowers in corresponding positions in adichogamous inflorescences so s fell to 0.135+/-0.027. In contrast, all-female flowers of female/male inflorescences selfed similarly to upper flowers on adichogamous inflorescences, elevating s (0.437+/-0.043). During 1997, male/female inflorescences sired more outcrossed seeds than female/male or adichogamous inflorescences, whereas during 1994 flowers on male/female inflorescences received fewer visits than those of adichogamous inflorescences, reducing their outcross siring success. Hence, sexual segregation limits geitonogamy and enhances outcross siring success when it does not affect pollinator behaviour, illustrating the importance of both female and male function in inflorescence design.     

Characterization of gravitropic inflorescence bending in brassinosteroid biosynthesis and signaling Arabidopsis mutants

The interaction between the plant hormones, brassinosteroids and auxins has been documented in various processes using a variety of plants and plant parts. In this study, detached inflorescences from brassinosteroid biosynthesis and signaling Arabidopsis mutants were evaluated for their gravitropic bending in response to epibrassinolide (EBR) and indole-3-acetic acid (IAA). EBR supplied to the base of detached inflorescences stimulated gravitropic bending in all BR biosynthetic mutants but there was no effect on the BR signaling mutant or wild type plants. When IAA was supplied to the base of BR mutant inflorescences both natural and EBR-induced gravitropic bending was inhibited. Treatment with the auxin inhibitors also decreased both natural and EBR-induced gravitropic bending. No gravitropic bending was observed when the apical tips of BR mutant inflorescences were removed. IAA treatment to the tips of decapitated BR mutant inflorescences restored gravitropic bending to values observed in the inflorescences with an apical tip, however, EBR applied to the tip had no effect. When decapitated inflorescences from BR mutants were treated with IAA to the base and either gel, EBR or IAA was applied to the tip; there was no gravitropic bending. These results show that brassinosteroids have a role in the gravitropic bending response in Arabidopsis and mutants serve to uncover this hidden contributor.     

Impact of floral herbivory by <Emphasis Type="Italic">Coleotechnites eryngiella</Emphasis> Bottimer (Lepidoptera: Gelechiidae) on the reproductive output of <Emphasis Type="Italic">Eryngium yuccifolium</Emphasis> Michaux (Apiaceae): a test of the reserve ovary model

The reserve ovary model is a key hypothesis proposed to explain why plants produce surplus flowers and posits that plants may utilize surplus flowers to compensate for losses from floral herbivory. We tested this hypothesis in the prairie plant Eryngium yuccifolium and its floral herbivore Coleotechnites eryngiella. At five Illinois tallgrass prairie sites, we collected central, primary lateral, and secondary lateral inflorescences from E. yuccifolium to determine whether damage by the larvae of C. eryngiella to the flowers in earlier developing inflorescences would be compensated for in later developing inflorescences. Coleotechnites eryngiella does extensive damage to the central and primary inflorescences and little damage to the secondary inflorescences. Later maturing inflorescences did not compensate for early damage by increasing seed production in later inflorescences. The secondary inflorescences of E. yuccifolium may only compensate for catastrophic damage done to the central and primary inflorescences early on in development, serve as additional advertisements for pollinators, act as pollen donors, or allow the plant to take advantage of “ecological windows” of high pollinator and low herbivore abundance. Our findings were spatially and temporally consistent and did not support the predictions of the reserve ovary model in the E. yuccifolium–C. eryngiella system suggesting that in this system, alternate, proximate, and ultimate causes need to be explored for the production of surplus flowers.     

Flower choice by honey bees (Apis mellifera L.): sex-phase of flowers and preferences among nectar and pollen foragers

Bees foraging for nectar should choose different inflorescences from those foraging for both pollen and nectar, if inflorescences consist of differing proportions of male and female flowers, particularly if the sex phases of the flowers differ in nectar content as well as the occurrence of pollen. This study tested this prediction using worker honey bees (Apis mellifera L.) foraging on inflorescences of Lavandula stoechas. Female flowers contained about twice the volume of nectar of male flowers. As one would predict, bees foraging for nectar only chose inflorescences with disproportionately more female flowers: time spent on the inflorescence was correlated with the number of female flowers, but not with the number of male flowers. Inflorescence size was inversely correlated with the number of female flowers, and could be used as a morphological cue by these bees. Also as predicted, workers foraging for both pollen and nectar chose inflorescences with relatively greater numbers of both male and female flowers: time spent on these inflorescences was correlated with the number of male flowers, but not with the number of females flowers. A morphological cue inversely associated with such inflorescences is the size of the bract display. Choice of flowers within inflorescences was also influenced predictably, but preferences appeared to be based upon corolla size rather than directly on sex phase.     

The evolution of empty flowers revisited

The evolution of plants that provide no form of reward for their pollinators is puzzling because they receive low numbers of pollinator visits and so have low reproductive success. To predict the evolutionary dynamics of empty morphs within a plant population, we modeled different foraging strategies that pollinators could use to avoid them. We predicted that the optimal strategy was to visit empty inflorescences randomly when these were infrequent but to use strategies such as visiting fewer flowers per inflorescence to avoid wasting time on them. As the frequencies of empty inflorescences increased, discriminating directly against empty morphs was more likely to be an optimal strategy than was avoiding the species altogether and switching to an alternative one. An experimental test of this model using artificial inflorescences showed that bumblebees used a variety of strategies to minimize time wasted on empty inflorescences. They showed weak discrimination against empty inflorescences but switched to an alternative type of inflorescence as the frequency of empty inflorescences increased. We predicted that empty morphs would be at a visitation rate disadvantage even when at low frequencies in a plant population. Differences in outcrossing rates, or male function, may explain how rewardlessness spreads in a plant population.     

Vegetative Proliferation and Secondary Proliferated Inflorescences Development in Grass Ischaemum barbatum Retz

We report the vegetative proliferation and new phenomenon of ＂secondary proliferated inflorescences＂ In the grass Ischaemum barbatum Retz, as determined by anatomical analysis of prepared sections of inflorescences. Leaves and shoots could be developed from the original splkelets of Inflorescences and plantlets developed when these shoots were transplanted to moist soil. ＂Secondary proliferated Inflorescences＂ is the first name here because some inflorescences that developed inadequacy are grown from the splkelet on the mother Inflorescence. Our investigation showed that this form of vegetative proliferation and secondary proliferated inflorescences development of L barbatum has arisen following late autumn fires of the previous year. It Is suggested that the sudden onset of a fire could lead to a hormone Imbalance or a chemical induction, which results in ephemeral vegetative proliferation even secondary proliferated inflorescences development in wild populations.     

A comparison of floral resource exploitation by native and invasive Argentine ants

Ants are often considered antagonists when they visit flowers because they typically steal nectar without providing pollination services. Previous research on ant–flower interactions on two species of South African Proteaceae in the Cape Floral Kingdom revealed that the invasive Argentine ant (Linepithema humile), but not native ants, displace other floral arthropod visitors. To determine how common Argentine ant use of inflorescences is, how Argentine and native ant visits differ in the numbers they recruit to inflorescences, and what factors may affect Argentine and native ant foraging in inflorescences, I surveyed 723 inflorescences in 10 species in the genera Protea and Leucospermum across 16 sites and compared ant presence and abundance in inflorescences with abundance at nearby cat food and jam baits. Argentine ants were the most commonly encountered ant of the 22 observed. Argentine ants, as well as six species of native ants were present in all inflorescences for which they were present at nearby baits. Mean Argentine ant abundance per inflorescence was 4.4 ± 0.84 (SE) ants and similar to that of Anoplolepis custodiens and Crematogaster peringueyi, but higher than observed for the other most commonly encountered native ants, Camponotus niveosetosus and Lepisiota capensis. Both Argentine ants and A. custodiens were more likely to be found foraging in spring and under humid conditions, and in inflorescences closer to the ground, with lower sucrose concentrations, and with a greater proportion of open flowers. Argentine ants were more likely to be found in Protea inflorescences, whereas A. custodiens and L. capensis more often visited Leucospermum inflorescences. Considering its displacement of floral arthropods and widespread use of Proteaceae inflorescences, the Argentine ant could be posing a serious threat to plant and pollinator conservation in this biodiversity hotspot.     

Observations on the reproductive ecology of Thalassia testudinum (Hydrocharitaceae) II. Leaf width as a secondary sex character

Short-shoots of Thalassia testudinum Banks ex König were collected from 5 sites in Florida. A total of 284, 625-cm² quadrat samples, containing 6182 shhort-shoots was analyzed for leaf width, inflorescence number and sex (the latter if determinable). Although leaf widths and reproductive densities differed at the 5 sites, leaf width was consistently greater when reproductive structures were present, and when the number of inflorescences increased. The mean number of inflorescences per short-shoot was significantly higher for shoots bearing male inflorescences compared to female shoots. Female inflorescences were normally solitary; male short-shoots usually had 2 or 3 inflorescences. Sex ratios were male-biased for 4 of the 5 sites. Comparisons of leaf widths between the sexes indicated that leaf width constituted a secondary sex character for this species. Female short-shoots tend to have narrower leaves than male short-shoots. This relationship should also be considered when evaluating the significance of morphogeographic and stress-related variation in leaf width for this species.