棉花竹花形态与结构研究

棉花竹（Fargesia fungosa）是箭竹属重要经济竹种,有关其花器官的形态与解剖结构研究至今尚无报道。本文通过对棉花竹花器官的形态与解剖结构进行观察和分析,结果显示棉花竹花序为“混合花序”,小穗基部具潜伏芽,由单个叶片形成的“佛焰苞”包裹多枚小穗。小穗单次发生,均长3.05±0.390 cm,每枚小穗具有3~7朵小花,小花均长1.85±0.167 cm,颖片2枚。每朵小花皆具有内、外稃各1片,3枚浆片,雄蕊3枚,雌蕊1枚组成。未成熟花药具有4药室,花药壁由外到内依次为表皮、药室内壁、中层和绒毡层。花药成熟后纵裂散粉。成熟花粉粒为2或3细胞型,且具有1个萌发孔。子房1室,上位,侧膜胎座,倒生胚珠,雌蕊具2分叉羽毛状柱头。花药发育异常,导致出现大量败育现象。     

云南竹亚科一些属种的增订

报道了云南竹亚科新名称１个,新组合１个,新异名１个,发现１个不合格名称,１个属在云南分布的新记录和１个种在我国分布的新记录。同时讨论了单枝竹属和空竹属的地理分布。     

竹类果实的多样性

竹类植物属于禾本科中的竹亚科,全世界有一千多种。中国是世界上竹子分布最广、种类最多的国家之一,竹林总面积约340万公顷,竹类植物有30多个属,400多种和亚种。 众所周知,竹子的寿命为几年、几十年甚至上百年,但大多数竹种一生中只开花结果一次,结实后植株便枯萎死亡。由于竹子的果实并不常见,因此关于其形态,一般读者知道的不多。本文仅就笔者的认识谈谈竹类果实的多样性。 在禾本科中,禾亚科植物的果实比较单纯,几乎全为颖果,仅有极少例外者,如鼠尾粟属和穇属等果皮和种皮分离为囊果。然而,在竹亚科中果实的大小、形状、颜色、果皮与种皮是否粘合,甚至果实的类型等,却是多种多样的。     

岷山北部竹类开花状况及对大熊猫的影响调查

2006年12月、2007年7～8月对岷山北部4县的竹类开花及大熊猫活动情况进行了调查.结果表明:(1)该区域竹种单一,仅有华西箭竹Fargesia nitida和缺苞箭竹F.denudata两种竹类,其中华西箭竹的分布面积最大;(2)该区域竹类从2004年开始出现开花现象,到2007年调查时开花过程已基本结束,开花竹面积达73 082 hm2,占竹类分布面积的51.36%;(3)在整个开花过程中,大熊猫实体被发现的频次增加,没有发现病、饿、死大熊猫的个体,现有大熊猫分布在竹类未开花的迭部县东部和舟曲县境内.此次竹类开花枯死,使该区域原有的大面积的大熊猫栖息地消失,因此需要加强对栖息地的保护和研究工作,使之尽快恢复成为大熊猫适合的栖息地.     

Chi竹属和牡竹属（竹亚科）叶表皮微形态特征

利用光学显微镜和扫描电镜,对Chi竹属21个种（包括Chi竹亚属5个种、孝顺竹亚属2种、单竹亚属4种绿竹亚属9种和亚属未定1种）以及牡竹属5种叶表皮微形态特征进行了观察和研究。所得结果表明气孔保卫细胞上乳突的数目和分布存在一定的规律,并具有一定的分类价值。绿竹亚属的叶表皮微形态特征界于Chi竹属和牡竹属之间,但更接近于Chi竹属。因此认为在分类处理上,将绿竹亚属置于Chi竹属比单独成立绿竹属更为合理。     

秦岭大熊猫主食竹的分类学研究（I）

研究为秦岭大熊猫主食竹系列报道之一,主要报道产于陕西长青国家级自然保护区大熊猫主食竹。该保护区内共有野生禾本科竹亚科植物4属、5种,栽培逸为野生的1属、1种,其中巴山木竹（Bashania fargesii）和秦岭箭竹（Fargesia qinlingensis）为该区域大熊猫最主要的采食野生竹种,龙头竹（Fargesia dracocephala）次之,由栽培逸为野生的金竹（Phyllostachys sulpurea）为大熊猫喜爱的竹种。     

箣竹属和牡竹属(竹亚科)叶表皮微形态特征

利用光学显微镜和扫描电镜,对箣竹属21个种(包括箣竹亚属5个种、孝顺竹亚属2种、单竹亚属4种、绿竹亚属9种和亚属未定1种)以及牡竹属5种叶表皮微形态特征进行了观察和研究。所得结果表明气孔保卫细胞上乳突的数目和分布存在一定的规律,并具有一定的分类价值。绿竹亚属的叶表皮微形态特征界于箣竹属和牡竹属之间,但更接近于箣竹属。因此认为在分类处理上,将绿竹亚属置于箣竹属比单独成立绿竹属更为合理。     

牡竹属三竹种的秆形质量与材性比较

通过牡竹属(Dendrocalamus) 3个竹笋品质佳的竹种（勃氏甜龙竹(D.brandisii)、马来麻竹(D. asper)、花吊丝竹(D. minor var. amoenus)）竹材形态质量及材性比较的研究,结果表明：种间立竹枝下高、相对全高差异显著或极显著,勃氏甜龙竹相对枝下高最小,立竹胸径、全高、枝下高、尖削度值、壁厚率均为最大;竹秆含水率随立竹年龄增大而下降,3年立竹竹秆含水率花吊丝竹>勃氏甜龙竹>马来麻竹,种间差异极显著;相对材积勃氏甜龙竹（1771.35cm 3 cm-1）>马来麻竹（1166.66 cm3 cm-1）>花吊丝竹（659.78 cm3 cm-1）,种间差异极显著;竹材密度随立竹年龄增大而提高,3a立竹竹材密度花吊丝竹（0.914 g.cm-3）>勃氏甜龙竹(0.812 g.cm-3)>马来麻竹（0.749 g.cm-3）,种间差异显著。综合分析勃氏甜龙竹、马来麻竹可作为优良的笋材兼用竹种,花吊丝竹宜作为笋用、观赏竹种推广应用。     

竹亚科酸竹属的研究

在对竹亚科散生竹全面研究基础上,本文对酸竹属进行了系统的整理和研究,讨论了本属与相近属之间亲缘和区别。本文确认有6种,其中有1新组合和5个新异名。     

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。     

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。     

唐古特雪莲花部特征及生殖分配的海拔差异

为探究高山植物生殖分配策略以及分析唐古特雪莲花部特征对海拔梯度的响应机制,该研究利用采样调查法和烘干称重法,对分布在青藏高原东缘不同海拔14个居群的唐古特雪莲花部特征和生殖分配进行了研究。结果表明:(1)繁殖分配随个体大小(地上生物量和株高)的增大呈线性递减趋势。(2)花期植株地上生物量、株高、管状小花数目、繁殖器官及营养器官生物量均随海拔升高呈线性递减趋势,管状小花生物量随海拔升高呈线性递增趋势。(3)花期管状小花数量及大小、繁殖器官生物量与营养器官生物量、雄蕊重量和雌蕊重量以及花粉数目与花丝长度之间均存在权衡现象。由此推论:(1)海拔作为外界因子对唐古特雪莲花部特征具有显著的影响,个体大小对其繁殖分配也存在潜在调控作用。(2)在不同海拔梯度上,唐古特雪莲有效地整合了有限的资源,其适应性特征之一就是通过减小个体大小来削弱营养生长以达到促进生殖生长的目的。     

Expression analysis and genetic mapping of three <Emphasis Type="Italic">SEPALLATA</Emphasis>-like genes from peach (<Emphasis Type="Italic">Prunus persica</Emphasis> (L.) Batsch)

SEPALLATA (SEP) MADS box genes play essential and diverse roles in reproductive organ development. To investigate the SEP gene function in peach we isolated three SEP-like genes, PrpMADS2, PrpMADS5, and PrpMADS7, which belong to distinct SEP gene clades. They appeared as single copy genes in the peach genome and were found to preferentially express in flowers and fruits. Arabidopsis transformants expressing 35S: PrpMADS2 were indistinguishable from wild-type plants. Overexpression of PrpMADS5 led to earlier flowering. Through chimeric repressor silencing technology, PrpMADS5 was found to function in floral organ development. Expression of PrpMADS7 in Arabidopsis caused a dramatic attenuation of both juvenile and adult growth phases and, in severely affected plants, it led to flower formation immediately after the embryonic phase. Two microsatellite markers were developed for PrpMADS2 and PrpMADS5 and assigned to the genetic linkage groups 5 and 1, respectively. PrpMADS7, previously identified as PrpAGL2, and PrpMADS5 were identified as potential loci to modify the flowering time and floral organs in Prunus species. Moreover, our results showed the diversification of SEP genes in peach. The gene sequences have been deposited in GenBank and will appear under the accession numbers BQ102369, EF440351, and EF440352.     

Dwarf bamboo as an ecological filter for forest regeneration

Quantitative relationships between the aboveground biomass of dwarf bamboo, Sasa nipponica, and the survivorship and emergence of seedlings of Abies homolepis, Fraxinus lanuginosa f. serrata, and Fagus crenata were estimated. We show that dwarf bamboo acts as an ecological filter since the responses of tree species differ according to the biomass of dwarf bamboo. Deer exclusion without management of dwarf bamboo would make it impossible for any tree species to regenerate due to rapid increases in the biomass of dwarf bamboo.     

基于数字标本探究绿绒蒿属植物花期的变化

近年来,随着全球气温的明显升高,气候变化引起的全球变暖受到人们的广泛关注.气候变暖会使植物物候发生改变,花期的变化能够直观地反映出植物对周围环境的适应,尤其是高山植物对气候变化更为敏感,因此探究高山植物的花期更具有代表性.为了解植物在气候变暖背景下花期的变化特征,并制定出合理的植物保护措施,该文以典型的高山植物绿绒蒿属...     

Isolation mechanisms between two sympatric Sophronitis (Orchidaceae) species endemic to Northeastern Brazil

Sophronitis sincorana and S. pfisteri (Orchidaceae) are endemic to the campo rupestre vegetation, northeastern Brazil, occurring sympatrically and flowering synchronously. In this work we studied the reproductive biology of both species and investigated reproductive barriers between them. Both species are partially self-compatible, pollinator dependent, and are pollinated by males and worker bees of Bombus brevivillus. Pollinaria are deposited on the anterior portion of the mesonotum of these insects in S. pfisteri, and on the scutellum in S. sincorana. The flowers of both species are deceptive, as they have a dry cuniculus. Morphological differences in the labellum and the gynostemium impede inter-specific pollination of S. pfisteri with pollen from S. sincorana. Very low fruiting results from inter-specific crosses of S. sincorana with pollen from S. pfisteri. Although viable seeds can be produced from experimental inter-specific crosses, no natural hybrids were found. Species integrity appears to be maintained by additive unidirectional reproductive barriers between them.     

Forest fragmentation and plant reproductive success: a case study in four perennial herbs

We assessed the effects of habitat fragmentation on reproductive success in natural populations of four forest herbs with differing life-history traits and whose distribution patterns appeared to be negatively affected by decreased habitat size and/or increased isolation: Carex sylvatica, Galium odoratum, Sanicula europaea and Veronica montana. Our aims were to test (1) whether habitat size and isolation are positively correlated with population size and isolation, respectively, (2) whether plant reproductive success, a major component of plant fitness, is reduced in small and/or isolated populations when also accounting for differences in habitat quality (edaphic conditions, light intensity) and the effects of plant size, and (3) whether species with different life histories are affected differently. There were significant positive relationships between habitat and population size and between habitat and population isolation in some, but not all of the species. We mostly found no negative effects of small population size or isolation on reproduction. However, reproductive success was reduced in small populations of Sanicula, and this effect was independent of differences in plant size and environmental conditions. The reduced fecundity in small populations may be a consequence of the Allee-effect, a possible mechanism being pollen limitation. Furthermore, the proportion of flowering ramets was reduced in small and isolated populations of Galium, which may have been caused by changes in population structure. Lastly, we found some evidence for largely outcrossing, non-clonal species to be more sensitive to reductions in population size, at least in terms of their reproductive success.     

蝴蝶兰花发育的分子生物学研究进展

蝴蝶兰花非常独特且高度进化,如萼片瓣化、瓣片特化为唇瓣、雌雄蕊合生成合蕊柱及子房发育须由授粉启动等,是单子叶植物花发育研究的理想材料。近年来蝴蝶兰花发育分子生物学取得了重要进展。该文就近年来国内外有关蝴蝶兰开花转换及花器官发育相关基因研究以及B类基因与兰花花被的进化发育关系方面的研究进展进行综述。研究表明:MADS基因在蝴蝶兰开花转换及花器官发育过程中起重要作用,推测其中的DEF(DE-FICIENS)-like基因早期经过2轮复制,形成了4类不同的DEF-like基因,进而决定兰花花被属性。蝴蝶兰花发育分子生物学的深入研究,将极大地利于通过基因工程手段提高蝴蝶兰花品质如花色改良及花期调控等,推动分子育种进程。     

Tree regeneration responses in a lowland Nothofagus-dominated forest after bamboo dieback in South-Central Chile

The bamboo Chusquea quila (Poaceae:Bambuseae) is the most abundant understory species ofNothofagus-dominated forests at low elevations inthe Chilean Lake District. Species of this genus strongly inhibit theestablishment and growth of tree species, especially those of the genusNothofagus. At intervals of many years, this bambooflowerssynchronously and dies, creating large-scale disturbances. The mainobjective of this study was to determine the influence of bamboo dieback ontreeregeneration, especially of shade-intolerant species. The forest studiedis a remnant stand of old-growth forest dominated by emergent individualsof N. obliqua and Eucryphiacordifoliawhich project about 10 m above a main canopy formed byAextoxicon punctatum, Laureliaphilippiana, and Podocarpus saligna. Treeseedlings that established prior to bamboo dieback were recorded in six gapsdensely covered by bamboo. After the dieback event in the early 1990's,recruitment, height growth and survivorship were monitored in four gaps duringtwo growing seasons. After the synchronous mass flowering and death ofChusqueaquila, both reorganization of advance regeneration and new seedlingrecruitment were observed in gaps. The advance regeneration consisted mainly ofthe shade-tolerant species A. punctatum,L. philippiana, and Amomyrtus luma.These species together with E. cordifolia accounted forover 90% of the total individuals in gaps. During the following twoseasons, c. 40% of the advance regeneration either died or was damaged.Root suckers of E. cordifolia and L.philippiana were taller and grew faster than the seedlings of otherspecies. Nothofagus obliqua was unable to establishadvanceregeneration in gaps formerly dominated by bamboo. New recruitment resulted inthe synchronized establishment of treeseedlings, especially less shade-tolerant species such as N.obliqua, Aristotelia chilensis,Rhaphithamnus spinosus, and E.cordifolia. These species recruited into the gaps almost entirelyduring the first season right after the bamboo dieback. However, by the end ofthe second season, these species had a lower density due to a combination oflower recruitment rate, shortened recruitment period, and greater mortalityratecompared to the shade-tolerant species. New bamboo seedlings grew fasterand were more abundant than tree seedlings, except for root suckers (bothnew establishment and advance regeneration) of E.cordifolia which is more likely to successfully recruit into thecanopy. Seedlings of N. obliqua compete poorly with bambooseedlings; its successful recruitment may require bamboo flowering coincidentwith a mast seed year for the tree species.