10种刚竹属植物花部形态的补充描述

首次补充和描述了黄古竹Phyllostachys angusta,乌芽竹P.atrovaginata,角竹P.fimbriligula,美竹P.mannii,早园竹P.propinqua,芽竹P.robustirames,水胖竹P.rubicunda,衢县红壳竹P.rutila,天目早竹P.tianmuensis,9种竹子的花部形态特征,并根据采得了可靠花枝标本对台湾桂 竹P.makinoi的花部形态特征作了增补和修订。     

葎草雌雄植株开花物候和花器官对干旱的响应差异

摘要：以蓓草（Humulusscandens）为实验材料,在控制土壤水分的条件下探究干旱对雌雄异株植物开花物候和花器官形态的影响,结果表明：干旱胁迫将导致蓰草雌雄种群花期提前．花期持续时间延长,雌花将比雄花提早开放;干旱胁迫下雄花的花序轴长、花序轴直径和花药粒径长均分别显著减小24．81％。29．07％和5．14％（P〈0．001,P=0．003,P=0．024）,花粉活力和花粉含量显著下降：干旱胁迫导致雌花的花序轴长、柱头长度和花序的平均花数量显著增大9．78％,70．62％和57．04％（P=0．039．P〈0．001．P〈0．001）;干旱胁迫下种子粒径长、种子粒径宽、种子单粒重和种子千粒重分别显著下降12．12％、12．59％、43．43％和15．38％（显著度水平均为P〈0．001）;干旱胁迫下雌雄植株的地上部分生物量均显著降低（P=0．002,P=0．020）,且雌株的生殖投入在干旱胁迫下显著高于雄株（P=0．049）。研究结果表明了蓰草雌雄植株开花物候及花器官对干旱的响应明显不同。与雄株相比．雌株在干旱胁迫下增加了生物量向生殖器官的分配,从而最大程度地减轻胁迫对其繁殖能力的影响。     

Morphological specialization of heterantherous Rhynchanthera grandiflora (Melastomataceae) accommodates pollinator diversity

• The tropical Melastomataceae are characterized by poricidal anthers which constitute a floral filter selecting for buzz‐pollinating bees. Stamens are often dimorphic, sometimes with discernible feeding and pollinating functions. Rhynchanthera grandiflora produces nectarless flowers with four short stamens and one long stamen; all anthers feature a narrow elongation with an upwards facing pore.
• We tested pollen transfer by diverse foraging bees and viability of pollen from both stamen types. The impact of anther morphology on pollen release direction and scattering angle was studied to determine the plant's reproductive strategy.
• Medium‐sized to large bees sonicated flowers in a specific position, and the probability of pollen transfer correlated with bee size even among these legitimate visitors. Small bees acted as pollen thieves or robbers. Anther rostrum and pore morphology serve to direct and focus the pollen jet released by floral sonication towards the pollinator's body. Resulting from the ventral and dorsal positioning of the short and long stamens, respectively, the pollinator's body was widely covered with pollen. This improves the plant's chances of outcrossing, irrespective of which bee body part contacts the stigma. Consequently, R. grandiflora is also able to employ bee species of various sizes as pollen vectors.
• The strategy of spreading pollen all over the pollinator's body is rather cost‐intensive but counterbalanced by ensuring that most of the released pollen is in fact transferred to the bee. Thus, flowers of R. grandiflora illustrate how specialized morphology may serve to improve pollination by a functional group of pollinators.

     

Comparative ontogeny of perfect and pistillate florets in Senecio vernalis (Asteraceae)

We studied the inflorescence, and in particular ontogeny and development of the florets in Senecio vernalis as a representative member of Asteraceae, using epi-illumination microscopy. Initiation and subsequent development of florets on the highly convex inflorescence apex occur acropetally, except for pistillate ray florets, which show a lag in initiation. Receptacular bracts derive from the receptacular surface after development of all florets. The order of whorl initiation in both disc and ray florets include corolla, androecium and finally the pappus, together with the gynoecium. Development of corolla lobes from a ring meristem occurs in bidirectional order starting from the lateral side, whereas stamens incept unidirectionally from the abaxial side. Concurrently with the inception of two median carpel primordia, a ring meristem develops at the base of the corolla from which pappus bristles differentiate in later stages. Pistillate ray florets show significant differences from perfect disc florets as reflected by the zygomorphic shape of the floral apex and a shift of floral merosity from pentamery to tetramery. Loss of stamens in ray florets occurs due to abortion of primordia after initiation.     

Redundancy in wildflower strip species helps support spatiotemporal variation in wild bee communities on diversified farms

Wildflower strips are a management practice increasingly used to provide floral resources to wild bees in agroecosystems. Yet, despite known spatiotemporal variation in wild bee communities, the degree to which different wildflower strip species consistently support wild bee communities is poorly understood. Additionally, whether such consistency is related to the functional roles wildflower species play (e.g., in supporting diverse, rare, or unique suites of bee species) has not been considered. Over three years and on four diversified farms, we evaluated spatiotemporal variation in wild bee communities and bee-flower interactions in wildflower strips to better understand the roles of flower strip species in supporting bees. We documented spatiotemporal variation in the abundance, richness, and composition of local wild bee communities. Certain wildflower species consistently supported the highest richness of wild bees across years. These wildflower species were regularly core members of the bee-flower interaction network, visited by both generalist and specialist bees. By contrast, wildflower species supporting the most unique suites of bees were variable in this role among farms. In order to select plant species for wildflower strips that consistently support a high diversity of wild bee communities within farm landscapes, it is useful to consider several different functional roles that plants may play. Whereas a handful of wildflower species may be visited by the majority of local wild bee species, achieving support for the remaining, and perhaps rarer, bee species will require planting additional flower species, which may appear redundant until the spatiotemporal variation in wild bee communities is more thoroughly considered. This functional approach to selecting wildflower species for bee conservation efforts is important for making practical recommendations to land managers and for guiding best management practices in different regions and with diverse management goals.     

Studies in the floral morphology and anatomy of nymphaeales

Floral morphology ofBrasenia schreberi Gmel. andCabomba caroliniana A. Gray was observed chiefly from an anatomical point of view. The receptacle ofB. schreberi is rather flat and a vascular plexus is observable in the mature flower. The vasculature in this plexus is so complex taht it is not easy to trace its structure in detail. by observation on small buds, it can be seen that the receptacular vasculature consists of a girdling bundle in the basal area and usually nine receptacular strands from which traces to the petals and stamens branch off. The vasculature in the receptacle is reconstructed and diagramatically shown as though split longitudinally and spread out in one plane. Floral vasculature inCabomba caroliniana is simpler, and is probably related to the smaller number of stamens and carpels. It also has a girdling bundle at the bottom of receptacle and this vasculature is suggested to be derived by simplification from aBrasenia-type vasculature. Evidence from floral anatomy suggests that these two genera are closely related. InNymphaea, a vascular plexus in the receptacle is also observed (Moseley, 1961; Ito 1983). The plexus ofBrasenia andNymphaea are not the same in their construction. Nevertheless, their fundamental floral vasculature is comparable and it is preferable to place them in the same family or same order.     

火龙果转录组测序、基因表达与功能分析

利用高通量测序技术对火龙果(Hylocereus undulatus Britt)红肉品种‘大红二号’的花芽、果实和枝条不同发育阶段的基因表达进行研究。结果显示,转录组测序共获得468.68 Gb原始数据(Raw data),从头组装获得239 152条转录本和162 519条unigene,约53.74%的unigene得到注释。分别在43 506条和16 251条unigene中检测到600 283个SNP位点和56 147个SSR位点。基因表达分析结果表明,在火龙果不同组织Fl510、Fl513、Fl514、Fl518、F711、F715、S513、S419中分别有31、7、5、152、17、63、17、8个特异表达的unigene。通过GO和KEGG富集分析,发现了一些组织特异的GO条目和代谢通路,如在Fl510中富集的类萜骨架生物合成代谢通路等。本研究还对参与花发育的候选基因进行了鉴定和表达分析,他们包括COL基因、FT-like基因、分生组织决定基因和器官决定基因等。     

臭椿花器官分化的初步研究

利用扫描电镜(SEM)和光镜(LM)对臭椿花序及花器官的分化和发育进行了初步研究,表明:1)臭椿花器官分化于当年的4月初,为圆锥花序;2)分化顺序为花萼原基、花冠原基、雄蕊原基和雌蕊原基。5个萼片原基的发生不同步,并且呈螺旋状发生;5个花瓣原基几乎同步发生且其生长要比雄蕊原基缓慢;雄蕊10枚,两轮排列,每轮5个原基的分化基本是同步的;雌蕊5,其分化速度较快;3)在两性花植株中,5个心皮顶端粘合形成柱头和花柱,而在雄株中,5个心皮退化,只有雄蕊原基分化出花药和花丝。本研究着重观察了臭椿中雄花及两性花发育的过程中两性花向单性花的转变。结果表明,臭椿两性花及单性花的形成在花器官的各原基上是一致的(尽管时间上有差异),雌雄蕊原基同时出现在每一个花器官分化过程中,但是,可育性结构部分的形成取决于其原基是否分化成所应有的结构:雄蕊原基分化形成花药与花丝,雌蕊原基分化形成花柱、柱头和子房。臭椿单性花的形成是由于两性花中雌蕊原基的退化所造成,其机理有待于进一步研究。