Annual Flowering Period Research Articles

ИНТРОДУКЦИОННОЕ ИЗУЧЕНИЕ MARRUBIUM INCANUM DESR. В ЮЖНО-УРАЛЬСКОМ БОТАНИЧЕСКОМ САДУ-ИНСТИТУТЕ

This work provides information on the introduction study of some biological features of M. incanum under the conditions of introduction in the botanical garden of Ufa. The tasks of the research included: detecting the onset of the main phenophases of growth and development, analyzing morphometric parameters and determining the success of the introduction of the species in new growing conditions. M. incanum is a long-lasting spring-summerautumn-green plant with a period of winter dormancy, spring awakening, with an average annual flowering period. The growing season is 6-6.5 months. Regrowth of shoots was noted in late April - early May. The appearance of buds on generative shoots on average begins at the end of June (27.06), the beginning of flowering - in the first decade of July (07.07). In terms of flowering duration, the species belongs to the group of long-flowering plants, this period is about 30 days. The beginning of seed maturation was noted in mid-August. Most morphometric parameters are characterized by a normal degree of variation (Cv-5.1-28.5%). Features such as the number of leaves on the generative shoot and leaf length are characterized by slight variation (Cv-1.2-4.3%). It has been established that the species goes through a full cycle of life development, including the formation of full-fledged seeds. Plants grow and develop perfectly, form a developed overground mass, but in winter time requires shelter, since plants are characterized by weak winter resistance and are able to freeze. Despite this, according to the assessment of the success of introduction, the studied species belongs to promising plants for cultivation and can be recommended for cultivation in the Southern Urals as medicinal raw materials and in cooking as seasoning.

Spatiophylogenetic modelling of extinction risk reveals evolutionary distinctiveness and brief flowering period as threats in a hotspot plant genus

Comparative models used to predict species threat status can help identify the diagnostic features of species at risk. Such models often combine variables measured at the species level with spatial variables, causing multiple statistical challenges, including phylogenetic and spatial non-independence. We present a novel Bayesian approach for modelling threat status that simultaneously deals with both forms of non-independence and estimates their relative contribution, and we apply the approach to modelling threat status in the Australian plant genus Hakea. We find that after phylogenetic and spatial effects are accounted for, species with greater evolutionary distinctiveness and a shorter annual flowering period are more likely to be threatened. The model allows us to combine information on evolutionary history, species biology and spatial data, calculate latent extinction risk (potential for non-threatened species to become threatened), estimate the most important drivers of risk for individual species and map spatial patterns in the effects of different predictors on extinction risk. This could be of value for proactive conservation decision-making based on the early identification of species and regions of potential conservation concern.

Detection and Microscopy of Alnus glutinosa Pollen Fluorescence Peculiarities

Alnus glutinosa is an important woody plant in Lithuanian forest ecosystems. Knowledge of fluorescence properties of black alder pollen is necessary for scientific and practical purposes. By the results of the study, we aimed to evaluate possibilities of identifying Alnus glutinosa pollen fluorescence properties by modeling ozone effect and applying two different fluorescence-based devices. To implement the experiments, black alder pollen was collected in a typical habitat during the annual flowering period in 2018–2019. There were three groups of experimental variants, which differed in the duration of exposure to ozone, conditions of pollen storage before the start of the experiment, and the exposure time. Data for pollen fluorescence analysis were collected using two methods. The microscopy method was used in order to evaluate the possibility of employing image analysis systems for investigation of pollen fluorescence. The second data collection method is related to an automatic device identifying pollen in real time, which uses the fluorescence method in the pollen recognition process. Data were assessed employing image analysis and principal component analysis (PCA) methods. Digital images of ozone-exposed pollen observed under the fluorescence microscope showed the change of the dominant green colour toward the blue spectrum. Meanwhile, the automatic detector detects more pollen whose fluorescence is at the blue light spectrum. It must be noted that assessing pollen fluorescence several months after exposure to ozone, no effect of ozone on fluorescence remains.

In situ observations of the basal angiosperm Amborella trichopoda reveal a long fruiting cycle overlapping two annual flowering periods.

Amborella trichopoda is the sole living angiosperm species belonging to the sister lineage of all other extant flowering plants. In the last decade, the species has been the focus of many phylogenetic, genomic and reproductive biology studies, bringing new highlights regarding the evolution of flowering plants. However, little attention has been paid to in situ A. trichopoda populations, particularly to their fruiting cycle. In this study, an A. trichopoda population was observed during three annual flowering cycles. Individuals and branches were labeled in order to monitor the fruiting cycle precisely, from the flowering stage until the abscission of the fruit. Fruit exocarp was green during the first 9 months following flowering, turned red when the next flowering started a year later then remained on the branch during another year, between fruit ripping and abscission. Presence of fruits with two stages of maturity on shrubs was always noticed. Germination tests showed that seeds acquired their germination capacity 1 year after flowering, when fruits changed color. A. trichopoda's fruiting cycle is a long process overlapping two annual flowering periods. These results introduce a new model for flowering and fruiting cycles. The availability of mature seeds on shrubs for more than 1 year is likely to maximize opportunities to be dispersed, thus promoting the survival of this basal angiosperm.

Pollination biology of Syngonanthus elegans (Eriocaulaceae - Poales)

Studies on the pollination biology of Eriocaulaceae are scarce although particularly interesting because of its inclusion in the Poales, a predominantly wind-pollinated order. The pollination biology of Syngonanthus elegans (Bong.) Ruhland was studied during two annual flowering periods to test the hypothesis that insect pollination was its primary pollination system. A field study was carried out, including observations of the morphology and biology of the flowers, insect visits and pollinator behaviour. We also evaluated seed set, seed germination and seedling development for different pollination modes. Although seeds were produced by self-pollination, pollination by small insects contributed most effectively to the reproductive success of S. elegans, resulting in the greatest seed set, with the highest germination percentage and optimum seedling vigour. The floral resources used by flower visitors were pollen and nectar that was produced by staminate and pistillate flowers. Self-pollination played a minor role and its consequence was inbreeding depression.

Spatial and temporal patterns of predation on seeds of the surfgrass Phyllospadix torreyi

Spatial and temporal patterns of predation on seeds of the seagrass Phyllospadix torreyi S. Watson were quantified at four sites near Santa Barbara, California, USA. Over a period of four flowering seasons during 1995 to 1998, monthly patterns of seed fall and intensity of seed predation were similar among sites, but were temporally quite variable. Abundance of dispersed seeds varied greatly both among seasons and years. Within any one year, seeds were present in the environment every month, but they peaked in abundance during the fall months following the annual flowering period. Seeds were more abundant during the earlier years of the study. The intensity of predation steadily increased throughout the study period, from a low of ≤10% seeds consumed during 1995 to ∼50% consumption by 1997, and it was not correlated with abundance of seeds in the environment. Pre-dispersal seed loss also was estimated in two flowering seasons by counting the numbers of seeds consumed prior to release from the plant, and was relatively low (<15%). No differences were detected among the four study sites in patterns of pre-dispersal loss. Field surveys were done at two sites to identify potential seed predators. Three of the most abundant species identified in these surveys were tested in the laboratory to determine size-specific patterns of feeding activity and to assess which early life stages of P. torreyi (fruits within spadices, dehisced fruits, seedlings) were most vulnerable to predation. All three of the early life stages were consumed. The crabs Pugettiaproducta (Randall) and Pachygrapsus crassipes Randall were much more voracious predators than the isopod Idotea resecata Stimpson.

Reproductive phenology and mating potential in a low density tree population of Couratari multiflora (Lecythidaceae) in central Amazonia

The reproductive phenology of a population of 39 adult trees of Cour- atari multiVora was studied in 'terra firme' forests located 90 km N of Manaus, Amazonas, Brazil. Trees of this species, found in low densities, were inventoried in a 400-ha plot in which only one tree > 20 cm DBH per 10 ha was encountered. This species flowers from January to June, with a peak in the mid-wet season (March), and fruits during the dry season (May-September). Median distances between synchronized flowering trees were 600 to 1000 m depending on the time of the flowering season. The number of synchronous flowering trees at each obser- vation date in the 400-ha plot was 14 or 17.5 per 1 d, 13 (both) per 15 d, and three or 13 per 30 d, depending upon which of the two methods was used to evaluate synchrony. Fifty percent of the flowering trees overlapped in flowering with six to seven other flowering trees growing within a radius of 1000 m during most of the annual flowering period. Outcrossing rates were 100 % and the relatively long distances between trees in flower at the same time, support the assumption that this species is pollinated by pollinators travelling distances as far as 1000 m.

Flowering, pollination, nectar standing crop, and nectaries ofEuterpe precatoria (Arecaceae), an Amazonian rain forest palm

Flowering and pollination biology of the monoecious palmEuterpe precatoria was studied in the forest of the “Reserva Ducke” near Manaus, Brazil, during two annual flowering periods (middle of October to end of March) between 1991 and 1993. Individuals produced one to four bisexual inflorescences per flowering period. Inflorescences have staminate and pistillate flowers in triads. The anthesis of the whole inflorescence averaged 26 days, with the male phase extending over the first 17 days, followed by six days without any open flowers, and the female phase covering the last three days. The distinct dichogamy of the inflorescence results in obligate outcrossing. The pollen-ovule ratio is high (42000). Both male and female flowers emit an almond oil-like scent and produce nectar in septal nectaries. The concentration and total amount of sugar of the nectar of female flowers (37% and 0.021 mg) were significantly higher than that of male flowers (9% and 0.007 mg). The nectar is hexose-rich and with a moderately high amino acid concentration (68 µg/ml).Euterpe precatoria seems to be a generally entomophilous palm with a predominance of beetles and bees as potential pollinators. The most constant visitors were beetles of the familiesCurculionidae, Chrysomelidae, Staphylinidae, and bees of the familyHalictidae. The actual composition of the insect spectrum depends on climatic and biotic factors. Additionally, wind pollination may occur. Fruit development lasted four months and ripe fruits are swallowed by toucans who thus disperse the seeds.

Evolution of Euphilotes (Lepidoptera: Lycaenidae) by seasonal and host shifts

The lycaenid butterfly genus Euphilotes, consisting of five species and several dozen subspecies, is confined to western North America. Each subspecies utilizes one or a few species of Eriogonum (Polygonaceae) as larval hosts; larvae feed entirely on pollen and developing seeds. Euphilotes populations are (with few exceptions) univoltine and fly in synchrony with the initial ( c. 2 weeks) annual flowering periods of their hosts. Euphilotes evolution coincides with shifts to new hosts, frequently with different bloom periods. Often both inter- and intraspecific populations occur in sympatry. Although interspecific populations may fly in synchrony and utilize the same hosts, sympatric intraspecific populations use different hosts and generally fly allochronically. Analyses of Euphilotes populations using biochemical, morphological, and life history characters, do not support either coevolution or sequential evolution with Eriogonum but are more consistent with opportunistic adaptation to new hosts having different bloom periods.

Evolution of Euphilotes (Lepidoptera: Lycaenidae) by seasonal and host shifts

The lycaenid butterfly genus Euphilotes, consisting of five species and several dozen subspecies, is confined to western North America. Each subspecies utilizes one or a few species of Eriogonum (Polygonaceae) as larval hosts; larvae feed entirely on pollen and developing seeds. Euphilotes populations are (with few exceptions) univoltine and fly in synchrony with the initial (c. 2 weeks) annual flowering periods of their hosts. Euphilotes evolution coincides with shifts to new hosts, frequently with different bloom periods. Often both inter- and intraspecific populations occur in sympatry. Although interspecific populations may fly in synchrony and utilize the same hosts, sympatric intraspecific populations use different hosts and generally fly allochronically. Analyses of Euphilotes populations using biochemical, morphological, and life history characters, do not support either coevolution or sequential evolution with Eriogonum but are more consistent with opportunistic adaptation to new hosts having different bloom periods.

Seed Production and Litter Fall in Some Eucalypt Communities in Central Queensland

Seed production and litter fall were studied for seven woodland communities, dominated by Eucalyptus spp., in central Queensland. Seed and capsule fall are usually completed between annual flowering periods, for each of the Eucalyptus spp. studied. A pattern of light and heavy seed production is common over different years. Annual seed yields up to 20 kg ha-1 (or c. 49 million seed ha-1) were estimated over the varying 1-3-year study periods. Litter fall followed expected trends, ranging from 900 to 2700 kg ha-1 year-1, with peak production in the warmer months. These litter yields, coupled with understorey grass production, could provide adequate fuel for a ground fire to occur in most years. The implications of these findings for woodland management under pastoral use are discussed.