青藏高原东缘高寒草甸植物群落的开花物候

利用2008年整个生长季的地面花期物候观测数据,初步研究了青藏高原东缘高寒草甸植物群落开花物候的动态、格局、参数间的联系及其与物种共存的关系.结果表明:植物群落的花期从5月初开始,8月上旬进入开花数目的高峰期,到10月初结束,遍及整个生长季节;不同物种进入花期的时间、峰值期及持续时间不同,各物种花期物候生态位相分离,但群落中大部分物种开花峰值期主要集中在7-8月;不同物种的开花峰值期时间与花期持续时间有负相关关系:开花越早的植物其花期持续时间越长;物种间的开花物候差异主要是由植物本身的特性和环境条件共同决定的,而群落水平上的开花物候格局主要受非生物因素的控制.

Abstract：

Based on the observation on the flowering phenology in the whole growth season of 2008, the dynamics, patterns, and relationships among various parameters of flowering phenology of alpine meadow plant community in eastern Qinghai-Tibetan Plateau were studied, and the potential effects of above-mentioned factors on the species coexistence of the plant community were approached. The flowering period of the plant community started from early May, came into peak period in the first ten days of August, and ended in early October, extending all over whole growth period. Different species had their different first flowering date, peak flowering period, and flowering duration, and their flowering phenologieal niches differentiated obviously. Most species had their peak flowering period centralized in July-August. There was a negative rela-tionship between peak flowering period and flowering duration: the earlier the flowering, the lon-ger the flowering duration. The differences in flowering phonology among the species were mainly determined by species per se characteristics and environmental conditions, but the flowering phe-nological pattern on community level was primarily controlled by abiotic factors.     

植物成花转变及成花逆转的研究进展

本文主要讨论了植物成花转变及成花逆转等开花研究中应用分子生物学技术所取得的一些进展,描述了成花决定态的特性,5个从拟南芥中分离获得的成花转变的基因,有关光受体的分子生物学研究和造成成花逆转的原因等。     

武汉大学樱花花期长度特征及预报方法

武汉大学樱花是武汉的一张"城市名片",开展樱花花期长度的预报工作,可为旅游部门管理工作和游客安排出行时间提供合理的参考。根据1979—2018年40年武汉大学樱园日本樱花树始花期和落花期的观测资料及同期气象资料的研究分析表明:(1)樱花的始花期和落花期在20世纪80—90年代期间有明显的提前;从20世纪90年代末开始至今,始花期与落花期变化趋势不明显,但变率较大,与全球气候变化停滞期相吻合;40年间花期长度变率很大,整体无明显的增多或减少的趋势。(2)平均始花期为3月14—15日,落花期为3月31日—4月1日,平均花期长度为18d。(3)花期长度与当年始花期日序数、开花期间平均气温、开花期间最高平均气温、最低平均气温和温度日较差平均值均呈负相关,与开花期间总降水量呈正相关。与开花期内平均极大风速值、平均降水量和日照时数等无明显相关性。(4)用1979—2015年共37年资料建立了樱花花期长度的单因子拟合、多因子回归及主成分分析模型,用2016—2018年3年资料进行检验,对武汉大学樱花花期长度进行了预报,取得了较好的试验效果。其中主成分回归模型、降水单因子拟合模型和多因子樱花花期长度回归模型预报效果最好,平均绝对误差在1.5d左右,后期将会把预报模型运用到实际的樱花花期预报工作中。     

FLC调控植物成花的分子机制研究新进展

FLC是植物成花关键抑制因子, 主要通过结合到其下游2个关键的成花促进基因(FT和SOC1)启动子上而抑制二者的表达。此外, 还可以与其它调控因子结合调控开花。然而, 关于FLC在成花调控中的具体分子机制仍需深入研究。该文主要结合8条成花调控遗传途径, 梳理近年来与FLC相关的新进展, 并展望了未来的研究方向。     

A three‐component system incorporating Ppd‐D1, copy number variation at Ppd‐B1, and numerous small‐effect quantitative trait loci facilitates adaptation of heading time in winter wheat cultivars of worldwide origin

The broad adaptability of heading time has contributed to the global success of wheat in a diverse array of climatic conditions. Here, we investigated the genetic architecture underlying heading time in a large panel of 1,110 winter wheat cultivars of worldwide origin. Genome‐wide association mapping, in combination with the analysis of major phenology loci, revealed a three‐component system that facilitates the adaptation of heading time in winter wheat. The photoperiod sensitivity locus Ppd‐D1 was found to account for almost half of the genotypic variance in this panel and can advance or delay heading by many days. In addition, copy number variation at Ppd‐B1 was the second most important source of variation in heading, explaining 8.3% of the genotypic variance. Results from association mapping and genomic prediction indicated that the remaining variation is attributed to numerous small‐effect quantitative trait loci that facilitate fine‐tuning of heading to the local climatic conditions. Collectively, our results underpin the importance of the two Ppd‐1 loci for the adaptation of heading time in winter wheat and illustrate how the three components have been exploited for wheat breeding globally.     

准噶尔无叶豆的开花物候与生殖特征

 为了研究沙漠稀有植物准噶尔无叶豆(Eremosparton songoricum)的开花物候特征及其对生殖成功的影响, 2005和2006年连续两年对其自然种群的开花物候和开花过程中的花部表型变化进行了观察, 并运用相对开花振幅、开花强度和开花同步性等开花物候指数研究了开花物候特征。结果表明: 准噶尔无叶豆在5月下旬至6月中下旬开花, 其种群、个体、花序和单花的花期分别历时26~29 d、8~10 d、5~7 d和2~3 d。单花开花进程依其形态和散粉特征可分为散粉前期、散粉初期、散粉盛期和凋谢期4个时期。其个体水平的开花物候进程(开花振幅曲线)呈渐进式单峰曲线, 具有很高的开花同步指数, 表现出一种集中开花的模式。开花物候指数与座果数之间的相关分析结果表明, 始花日期与花期持续时间存在负相关关系, 而与开花数和座果数存在正相关关系; 花期持续时间与开花数和座果数存在显著正相关关系。准噶尔无叶豆个体开花物候在很大程度上是由其遗传因子决定的, 而开花物候在年度间的变异, 可能是由于荒漠气候的差异(主要是水分和温度的差异)所引起的。作为沙漠窄域分布特有种, 准噶尔无叶豆在环境和人为干扰的双重选择压力下, 为了吸引更多的传粉者访问而达到生殖成功, 形成了大量集中开花的模式。     

高等植物开花诱导途径信号整合的分子机制

开花是高等植物从营养生长到生殖生长的重要转折点。花分生组织的形成是开花植物对内外环境信号的响应。近年来在开花诱导方面已获得许多研究成果,我们介绍了高等植物开花诱导的4条主要途径（光周期途径、春化途径、自主途径和赤霉素途径）和复杂的信号整合机制。     

中国特有植物血水草开花物候与生殖特性

于2008年3-5月对分布在井冈山的血水草(Eomecon chionantha Hance )5个自然种群的开花物候进行了观察,运用开花振幅、相对开花强度和开花同步性等指数研究了其开花物候特征及其对该种生殖成功的影响.结果表明:血水草开花时间为3月下旬-5月上旬,种群花期历时24 ～46 d,个体平均开花持续时间为11～21 d,单花花期一般为3～5d;井冈山血水草种群的开花物候进程呈单峰曲线模式具有一个开花高峰期,表现出一种“集中开花模式”;与大多数亚热带植物一样,血水草具有较低的相对开花强度,分布频率集中在10％ ～30％.开花物候指数与生殖间的相关分析结果表明:始花时间与花期持续时间呈显著负相关,而与开花数和坐果率呈显著正相关;花期持续时间与开花数和坐果率呈显著正相关;同步性指数与始花时间、开花数、花期持续时间呈负相关.血水草“集中开花模式”是其在长期的进化过程中适应周围气候条件及生境的一种生殖保障.     

The strength of assortative mating for flowering date and its basis in individual variation in flowering schedule

Although it has been widely asserted that plants mate assortatively by flowering time, there is virtually no published information on the strength or causes of phenological assortment in natural populations. When strong, assortative mating can accelerate the evolution of plant reproductive phenology through its inflationary effect on genetic variance. We estimated potential assortative mating for flowering date in 31 old‐field species in Ontario, Canada. For each species, we constructed a matrix of pairwise mating probabilities from the individual flowering schedules, that is the number of flower deployed on successive dates. The matrix was used to estimate the phenotypic correlation between mates, ρ, for flowering date. We also developed a measure of flowering synchrony within species, S, based upon the eigenstructure of the mating matrix. The mean correlation between pollen recipients and potential donors for flowering date was  = 0.31 (range: 0.05–0.63). A strong potential for assortative mating was found among species with high variance in flowering date, flowering schedules of short duration and skew towards early flower deployment. Flowering synchrony, S, was negatively correlated with potential assortment (r = ?0.49), but we go on to show that although low synchrony is a necessary condition for phenological assortative mating, it may not be sufficient to induce assortment for a given phenological trait. The potential correlation between mates showed no seasonal trend; thus, as climate change imposes selection on phenology through longer growing seasons, spring‐flowering species are no more likely to experience an accelerated evolutionary response than summer species.     

拟南芥开花时间调控的分子基础

在合适的时间开花对大多数植物的生存和成功繁衍极为重要。开花时间受错综复杂的环境因素和植物自身的遗传因子影响,由开花调控因子所构成的光周期、春化、温度、赤霉素、自主以及年龄等至少6条既相互独立又相互联系的遗传途径调控。该文综述了有关拟南芥(Arabidopsis thaliana)开花时间调控的分子机制的最新研究进展,并对今后的研究进行了展望。     

Low temperature influence on flowering in Citrus. The separation of inductive and bud dormancy releasing effects

The flowering response of Owari Satsuma mandarin ( Citrus unshiu Marc) to low temperature treatments has been determined using potted trees and in vitro bud cultures. In potted trees the chilling treatments released bud dormancy and enhanced both sprouting and flowering, but these two responses could not be separated. However, bud cultures showed no dormancy, and a specific effect of low temperature on flower induction was demonstrated. Low temperature appears to have a dual effect, releasing bud dormancy and inducing flowering. Potential flower buds have a deeper dormancy than vegetative buds, and the first stages of flower initiation seem to occur before the winter rest period.     

Flowering patterns among angiosperm species in Korea: diversity and constraints

Because of the complexities of their flowering parameters, it is difficult to make generalizations about flowering phenology among temperate angiosperms. We examined patterns of flowering time and duration among 2867 Korean angiosperm species, and these patterns were associated with climatic factors. The effect of taxonomic membership was also tested. Overall data pooled over species from 165 families showed that 63.8% of these angiosperms flowered in summer, 19.5% in spring, 16.5% in autumn, and 0.2% in winter. Summer and autumn flowering periods were significantly longer than springtime events. Both mean monthly temperature and precipitation were strongly positively correlated with the number of species in flower, but not with flowering duration. The seven largest families differed in their flowering season and duration; both parameters were also segregated among genera within large families. In a two-way analysis, both flowering season and family membership exerted significant effects on flowering duration. These results demonstrate that the evolutionary influence on flowering time and duration can be observed at the community level when two factors are considered, i.e., the interaction of flowering parameters and the taxonomic composition of species within those communities.     

引种保护植物对西双版纳极端冷年的春季物候响应

气温被普遍认为是春季物候期最主要的控制因子之一, 然而低温对植物物候的影响效应一直都存在不同的观点。西双版纳由于地处热带地区的北缘, 其气温相对于赤道附近的热带地区较低。自1959年以来, 西双版纳热带植物园引入了来自世界各个热带地区的4万余种植物进行保护, 之前的研究证明西双版纳的低温对这些引种植物的生长有很大影响。因此,1974年西双版纳出现的极端低温势必对引种植物造成极大威胁, 同时也是对这些植物低温适应能力的一个考验。通过对比43种引种植物物候期(生长抽梢期与开花期)在1974年与常年的差异情况, 分析不同来源(热带亚洲、热带美洲与热带非洲)引种植物对西双版纳低温的适应性。结果表明, 经历西双版纳1974年初的极端低温之后, 使81%的引种植物生长抽梢期提前, 同时也造成35%的引种植物在该年没有开花; 而植物生长抽梢提前的主要原因则是极端低温以及低温过后气温迅速回升。引种植物均能顺利度过1974年的最冷时期, 并出现生长抽梢物候, 这意味着引种植物在经历极端低温之后都能够进行正常的生长活动, 但极端低温对引种植物繁殖活动的不利影响大于其对生长活动的影响; 引种植物对西双版纳极端低温的适应能力由大到小顺序依次为: 亚洲来源植物>美洲来源植物>非洲来源植物。因此在迁地保护植物的选择过程中, 应多选择亚洲热带植物, 其次为美洲热带植物, 而对非洲热带植物的引入则需谨慎考察。     

The rhythmic expression of genes controlling flowering time in southern and northern populations of invasive Ambrosia artemisiifolia

Aims Flowering time has been suggested to be an important adaptive trait during the dispersal of invasive species, and identifying the molecular mechanisms underlying flowering time may provide insight into the local adaptation during the process of invasion. Here, we conducted a preliminary exploration on the genetic basis of the differentiation of flowering time in Ambrosia artemisiifolia .Methods Using relative real-time fluorescent quantitative polymerase chain reaction, we investigated the expression levels of eight flowering-related genes, including AP1, FT, SOC1, CRY2, FKF1, GI, CO2 and SPY, in leaves and flowers at different time points in individuals from northern Beijing and southern Wuhan populations that exhibit significant differences in flowering times to identify any rhythmic changes in gene expression and their association with differential flowering times.Important findings The differentiation of flowering time in the A. artemisiifolia populations was closely associated with five genes involved in flowering pathways. The floral pathway integrators FT and SOC1 and floral meristem identity gene AP1 exhibited increased expression during flowering. The photoreceptor CRY2 in the light-dependent pathway and the SPY gene in the gibberellin pathway displayed specific expression patterns over time. In earlier-flowering Beijing plants, CRY2 expression was lower and SPY expression was higher than in Wuhan plants. The expression patterns of these five genes suggest a molecular basis for the differentiation of flowering time in A. artemisiifolia .     

浙江低山地区多用途植物无患子的开花物候特征

无患子(Sapindus mukorossi Gaertn.)是我国长江以南地区传统的重要绿化树种,其果皮富含皂苷,种仁富含油脂,是国家林业局审定的新型木本油料树种之一。为研究多用途树种无患子在浙江低山地区的开花特征,2012年和2013年连续两年对位于浙江省天台县9年生无患子人工林在群体、个体、花序和单花水平进行开花物候观测和比较,并运用开花日期、相对开花强度和同步性等指数研究了无患子开花物候特征。观察结果显示:无患子花呈浅黄白色,花的类型有雄花和两性花,没有发现雌花。雄花较两性花大(花径分别为5.09 mm和3.72 mm),雄蕊多为8枚,个别7或9、10枚;雌蕊退化仅留下浅绿色凸起。两性花花萼稍抱拢,花药藏于花被片下,雄蕊大多8枚,极少数7枚或9枚,柱头高于花药并伸出花苞,子房一般具3室,极少数4室或仅2室。无患子2012年的开花进程略早于2013年,其花期集中在在5月中旬至6月上旬,单花从花蕾膨大到花朵凋谢一般为8—9 d。在2012年和2013年,无患子在群体、个体和花序水平的花期约为30 d、20 d、11 d和28 d、19 d、13 d。个体水平的开花振幅均呈单峰曲线,年际间相似性较高;开花同步性在个体水平同步性较高(同步指数为0.868),表现出一种大量、集中的开花式样;相对开花强度在单株间分布范围相对宽泛,但主要分布在30%—40%,在年际间和年际内均呈现极显著差异。花期同步指数在两年的变异范围分别是0.81—0.97和0.70—0.98,不同单株开花同步性在年际内差异极显著,但在年际间差异性则不显著。由此可见,无患子的生殖资源分配存在明显的时空差异,较长的花期可以减少非法花粉的干扰、保持其种群基因多样性,遗传因子是决定无患子开花物候的主要因素,生态环境对无患子开花物候的影响还需进一步研究,本研究以期为探索无患子开花的主要限制因子奠定基础。     

植物开花时间的遗传调控通路研究进展

开花时间对植物的繁殖成功至关重要。广泛分布的物种经常发生开花时间的分化, 从而能够更好地适应不同的环境条件。为了探索植物开花行为发生适应性分化的分子机制, 首先要明确调控开花行为的遗传通路。本文梳理了植物各类群调控开花时间的遗传通路, 以期为开花时间适应性分化的分子机制研究提供依据。 植物从营养生长向繁殖转变时, 其开花行为主要受到光照、温度、水分等外界环境因子和赤霉素等内在因素的影响。通过对模式植物拟南芥(Arabidopsis thaliana)和其他类群的研究, 总结出了调控植物开花时间的6条通路, 包括日照长度和光质影响开花的光依赖通路, 长时间冷暴露后促进植物开花的春化通路, 高温或低温环境影响开花的温度通路, 以及赤霉素通路、年龄通路和自主通路3条内部调节过程。植物开花时间调控的6条上游通路信号传递到下游的开花整合基因FT(FLOWERING LOCUS T)和SOC1(SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1), 整合基因将这些复杂的调节因子整合后进一步传递到下游花分生组织, 从而启动开花。此外, 非编码RNA、转座子对开花时间的调控也具有重要作用。部分遗传通路被证实在植物适应环境的过程中起到了重要作用。目前对植物开花调控的研究已经有一百多年历史, 理论相对成熟。然而, 仍然存在许多具有争议和未解决的问题, 如开花基因的表达方式、开花行为的特殊调控机制、开花时间变异的适应性意义等等, 需要更进一步的研究。     

The effect of cold, anoxia and ethylene on the flowering ability of buds of Cichorium intybus

The apical bud and the axillary buds of Witloof chicory ( Cichorium intybus L. cv. Tardive d'Anvers) remain in the vegetative state if they are left on the root and maintained at 18°C. Flowering occurs in long days of 16 h after a pretreatment of either 8 weeks at 3°C, 3 days in complete anoxia at 15°C, or 4 days in the presence of ethylene (1000 ppm) at 15°C. In contrast, the adventitious buds which spread out on the root after ablation of the collar flower in a photoperiod of 16 h without particular pretreatment. The grafting of apical buds onto roots after different treatments shows that cold and ethylene act on the root, whereas anoxia acts directly at the level of the bud. It seems that the inhibition of the flowering of preformed buds (apical and axillary) stems from the collar. A hypothesis is proposed to explain this inhibition and why it is broken by cold, anoxia and ethylene.     

Mass flowering of dipterocarp forests in the aseasonal tropics

At irregular intervals of 2 to 10 years the aseasonal tropical rain forests in west Malesia come into heavy mass flowering, followed by mast fruiting. During a heavy flowering almost half the mature individuals and over 80% of the canopy and emergent tree Species in a forest may flower. This involves over 200 tree species in a forest flowering over a short period of 3–4 months. The pollination needs during a mass flowering appears to be overcome in several ways. A rapid increase in the number of pollinators seems to occur in the forest. This is partly caused by the migration of pollinators from the fringes of the forest to forage on the superabundance of flowers. At the same time, some groups of plants which share common pollinators appear to reduce pollinator competition by flowering in interspecific sequence. Many members of the family Dipterocarpaceae have evolved sequential flowering too. They also share unique pollinators, common flower thrips which appear to build up rapidly in numbers by feeding and breeding on the millions of dipterocarp flower buds which are present several weeks before the flowering. The environmental cue for this irregular, but widespread mass flowering can be traced to a small dip of about 2° C below mean night-time temperature for 4 or 5 nights. The conditions for such temperature drops occur during El Nino events.     

A comparison of in vitro with in vivo flowering in bamboo: Bambusa arundinacea

Seedling explants of Bambusa arundinacea were cultured in a Murashige & Skoog (MS) based liquid medium, supplemented with sucrose (2), coconut water (5) and 6-benzylaminopurine (2.2 μM). In 3–6 months about 70 of the cultures flowered. A comparison was made between in vitro and in vivo flowering. Though smaller in size, in vitro florets were morphologically comparable to the in vivo florets. Anthesis in in vivo flowering took place in the morning hours. It was more or less synchronized and was dependent on the atmospheric temperature and humidity. The lemma and palea opened to expose both androecium and gynoecium to the pollinating agent (wind). In in vitro flowering, some florets opened as in their in vivo counterparts, some did not open but the anthers protruded from the tip of the partially opened lemma and palea. Anthesis was not synchronized under in vitro conditions. Pollen fertility in in vivo and in vitro flowerings were approximately 93 and 31 respectively. Studies by scanning electron microscopy showed some discrepancies in the pollen wall development in vitro. The trifid stigmas of in vivo florets were highly feathery with many papillae and withered soon after pollination or within few hours. The stigmas of in vitro developed florets were smaller with fewer and stouter papillae. They remained turgid for relatively longer periods. Seed production in in vivo flowering was profuse whereas in in vitro flowering seeds were produced only when many florets opened at the same time, in the same culture vessel. This revised version was published online in June 2006 with corrections to the Cover Date.