Individual flowering schedule, fruit set, and flower and seed predation in Vaccinium hirtum Thunb. (Ericaceae)

2002 ◽  
Vol 80 (1) ◽  
pp. 82-92 ◽  
Author(s):  
Suzuki Mahoro

Flowering phenology is a trait that determines, in part, the reproductive success of plants. In this study, the variation in flowering schedule among individuals in four subpopulations of Vaccinium hirtum Thunb. (Ericaceae) and the effects of pollinators, flower predators, and predispersal seed predators on fruit production of individuals for 2 years were investigated. To describe variation in the flowering schedule among individuals, new methods for calculating two quantitative indices, rank order and degree of synchrony with others, are presented. The methods are suitable for quantifying between-individual differences in the synchronous schedule of a temperate spring-bloom species. The 2-year phenological census showed that there was variation in flowering schedule within local subpopulations. In all subpopulations, the flowering rank was retained for 2 years, and in two subpopulations, the relative synchrony of individuals was also retained. Correlation analysis between flowering schedule and fruit set suggested that early-flowering individuals were at a disadvantage regarding pollinator availability. However, weevil and fly larvae attacks often counteracted the disadvantage; later-flowering individuals were predated more intensively than early-flowering ones. The response of V. hirtum subpopulations to the selection pressure against early flowering may be disturbed by temporal and spatial variations in the influence of pollinators and predators.Key words: flowering schedule, phenotypic variation, pollination, predispersal seed predation, flower predation, Vaccinium.

2011 ◽  
Vol 59 (8) ◽  
pp. 713 ◽  
Author(s):  
Mariana Tadey

Monttea aphylla is an aphyllus shrub abundant in the Monte Desert, Argentina. This species presents particular floral syndromes including violet, tubular flowers with trichome elaiophores that produce oil. Oil flowers are associated with specialised bees with an oil-collecting apparatus. To better understand the reproductive biology of M. aphylla, the mating system, flowering phenology, the associated pollinator assemblage and foraging behaviour was determined at the southern-most part of its distributional range. Results were compared with those of previous studies and discussed. At this southern location M. aphylla is a self-incompatible species; it relies on pollinators for fruit production and presented a low fruit set. Flowering occurred during the spring, from October to December. M. aphylla was pollinated by three species of bees (Apidae); two generalist species (Centris brethesi and Mesonychium jenseni) and one specialist to M. aphylla (Centris vardyorum). M. jenseni is a cleptoparasite of Centris species. Centris species are oil-collecting bees and showed territorial behaviour (i.e. they always visited a restricted group of plants which they protected from other visitors), they visited several flowers/plants, which enhanced geitonogamous self-pollination and reduced pollination efficiency, and which might explain the low natural fruit set observed in M. aphylla. C. vardyorum was the most important pollinator of M. aphylla in the study area. The reproductive biology of M. aphylla differs along its distributional range. Apparently, southern populations of M. aphylla are more specialised than the northern populations, the former being pollinated by a few related pollinator species whereas at the northern location a variety of visitors were observed.


Botany ◽  
2021 ◽  
Author(s):  
Takashi Y. Ida ◽  
Gaku Kudo

Phenological responses of plants to temperature dynamics are receiving attention due to the ongoing climate change. Most previous phenological studies have focused on flowering phenology rather than fruiting phenology. However, at mid-latitudes, the air temperature periodically changes during the growing period of plants. Hence, cool temperatures early and late in the growing period may affect reproductive success through pollination and fruit-development processes. To evaluate the linkages between reproductive phenology and success, we compared the phenologies, photosynthetic capacities, and fruit-set rates among 25 species within a cool-temperate community in northern Japan. The ambient temperature during the flowering periods of individual species increased with delays in flowering-onset time, whereas the ambient temperature during fruit-development periods was highest for species which bloomed in July. Fruit-set success among species was positively correlated with the ambient temperatures during the reproductive periods, and with the photosynthetic capacity. Fruit production of early-blooming species was limited by cool temperatures during the flowering period, presumably because of low pollinator activity, whereas that of late-blooming species was limited by cool temperatures during the fruit-development period because of slow fruit-development (i.e., sink limitation). Thus, limiting factors of fruit production varied depending on the flowering phenology of individual species within a community.


HortScience ◽  
2004 ◽  
Vol 39 (7) ◽  
pp. 1601-1606 ◽  
Author(s):  
Tina M. Rivera ◽  
Martin F. Quigley ◽  
Joseph C. Scheerens

The commercial and ornamental potential of three apple-berry polyculture systems was ascertained by monitoring the above-ground performance of component species in plots of `GoldRush' apple (Malus ×domestica Borkh.) trees on M.7 rootstock cropped with either blackberry (Rubus spp. L. `Navaho'), edible honeysuckle (Lonicera caerulea L. `Blue Belle' and `Blue Velvet'), or jostaberry (Ribes nidigrolaria Bauer `Josta') as understory plants. Polyculture plots and corresponding monoculture controls were established in 1999, with berry plants at recommended (R) or close [(C), half-recommended] spacings. Blackberries and jostaberries planted in monoculture at recommended spacings [i.e., control (R) plots] amassed dry weights >1 kg/plant by Fall 2001; the dry weight of edible honeysuckle from comparable plots was slightly >0.3 kg/plant. In 2001, blackberry yield (3.1 kg/plant) and fruit weight (3.4 g) were typical of `Navaho' plantings of similar age, whereas jostaberry was only moderately productive (yield = 286 g/plant; fruit weight = 1.4 g). Edible honeysuckle productivity (yield = 13 g/plant, fruit weight = 0.5 g) was minimal, due to disparate flowering phenology between cultivars. `GoldRush' apple growth and productivity (yield = 25 kg/tree; fruit weight = 158 g) was consistent with values expected for trees of similar age. Blackberry plant dry weights were reduced by 20% to 33% when planted at close spacing, whereas blackberry yields were reduced 35% to 38% when grown in polyculture with apple. Both polyculture and plant spacing significantly reduced jostaberry dry weights (i.e., 12% and 24%, respectively) relative to the control, but neither significantly affected jostaberry yield. Conversely, both close-spaced planting and the presence of an apple tree improved the yield of edible honeysuckle. Apple performance was not affected by the presence of an edible honeysuckle understory, but apple growth factors were reduced in blackberry and jostaberry polycultures by as much as 65%. Apple bloom, fruit set, and yield were also significantly reduced in apple-blackberry and apple-jostaberry plots, with fruit numbers/tree averaging <5 in all except the apple-blackberry (C) treatment. None of the polyculture treatments studied were suitable for profitable fruit production. However, each of the polyculture constituents exhibited unique, beneficial attributes with respect to their use as components within an edible landscape.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 543c-543
Author(s):  
Ami N. Erickson ◽  
Albert H. Markhart

Fruit yield reduction due to high temperatures has been widely observed in Solanaceous crops. Our past experiments have demonstrated that Capsicum annuum cultivars Ace and Bell Boy completely fail to produce fruit when grown at constant 33 °C. However, flowers are produced, continually. To determine which stages of flower development are sensitive to high temperatures, pepper buds, ranging in size from 1 mm to anthesis, were exposed to high temperatures for 6 hr, 48 hr, 5 days, or for the duration of the experiment. Fruit set for each bud size was determined. Exposure to high temperatures at anthesis and at the 2-mm size stage for 2 or more days significantly reduced fruit production. To determine whether inhibition of pollination, inhibition of fertilization, and/or injury to the female or male structures prevents fruit production at high temperatures, flowers from pepper cultivars Ace and Bell Boy were grown until flowers on the 8th or 9th node were 11 mm in length. Plants were divided between 25 °C and 33 °C constant growth chambers for 2 to 4 days until anthesis. At anthesis, flowers from both treatments were cross-pollinated in all combination, and crosses were equally divided between 33 or 25 °C growth chambers until fruit set or flowers abscised. All flower crosses resulted in 80% to 100% fruit set when post-pollination temperatures were 25 °C. However, post-pollination temperatures of 33 °C significantly reduced fruit production. Reduced fruit set by flowers exposed to high temperatures during anthesis and pollination is not a result of inviable pollen or ovule, but an inhibition of fertilization or initial fruit development.


2016 ◽  
Vol 113 (29) ◽  
pp. 8041-8048 ◽  
Author(s):  
Kelly R. Zamudio ◽  
Rayna C. Bell ◽  
Nicholas A. Mason

Almost 30 y ago, the field of intraspecific phylogeography laid the foundation for spatially explicit and genealogically informed studies of population divergence. With new methods and markers, the focus in phylogeography shifted to previously unrecognized geographic genetic variation, thus reducing the attention paid to phenotypic variation in those same diverging lineages. Although phenotypic differences among lineages once provided the main data for studies of evolutionary change, the mechanisms shaping phenotypic differentiation and their integration with intraspecific genetic structure have been underexplored in phylogeographic studies. However, phenotypes are targets of selection and play important roles in species performance, recognition, and diversification. Here, we focus on three questions. First, how can phenotypes elucidate mechanisms underlying concordant or idiosyncratic responses of vertebrate species evolving in shared landscapes? Second, what mechanisms underlie the concordance or discordance of phenotypic and phylogeographic differentiation? Third, how can phylogeography contribute to our understanding of functional phenotypic evolution? We demonstrate that the integration of phenotypic data extends the reach of phylogeography to explain the origin and maintenance of biodiversity. Finally, we stress the importance of natural history collections as sources of high-quality phenotypic data that span temporal and spatial axes.


2021 ◽  
Vol 13 (13) ◽  
pp. 20056-20065
Author(s):  
Maria Theresa ◽  
Appukuttan Kamalabai Sreekala ◽  
Jayalakshmi Mohanlal

Ophiorrhiza caudata is a creeping, perennial herb distributed along wet and shady areas. The species is distylous with two distinct floral morphs: pin and thrum. Flowering usually occurs during the monsoon season. No particular difference was noticed in the flowering phenology of the two morphs. Presently the species is self-incompatible, however, it shows a tendency towards intramorph compatibility. Fruit set is above 60% in open pollination and intermorph pollination. Bees and butterflies are the major pollinators. The pollen flow between the two floral morphs varies depending upon floral morphology and pollinators. Fruit is a bi-valved capsule which dehisces by a splashing drop mechanism. The seeds are very minute. The rate of seed germination and seedling establishment in the wild condition is very poor due to adverse climatic factors. Ophiorrhiza caudata is struggling for survival in its natural habitat, where habitat fragmentation, climatic factors and poor seedling establishment could account for its narrow distribution.


2017 ◽  
pp. 67
Author(s):  
Steven P. Mclaughlin ◽  
Ryan R. Williams

Several researchers have noted that flowering in Agavaceae requires substantial resources, but few studies have attempted to directly measure such resources. T his study addresses the hypothesis that fruit set in Hesperaloë funifera is limited by available carbohydrates. The accumulation of total non-structural carbohydrates (TNC) prior to flowering was measured, and total requirements for carbohydrate were estimated. Hesperaloë funifera was found to accumulate fructans, and roots were an important organ for storage of accumulated carbohydrates. Carbohydrates stored in the plant prior to flowering are sufficient to meet only about onethird of the carbohydrate needed to produce an average inflorescence with 1 % to 2% fruit set. All of the carbohydrate produced by photosynthesis from May through August is needed to support flowering and fruit production. Low percentage fruit set in Hesperaloë funifera is probably due to a deficiency of carbohydrate resources.


1989 ◽  
Vol 111 (4) ◽  
pp. 367-371 ◽  
Author(s):  
A. C. Hansen ◽  
X. Cui

Two models of the yaw behavior of horizontal axis wind turbines are presented and discussed. Emphasis in this paper is on the description of the models and underlying assumptions with details of the equations and solution methods referenced in technical reports. The more complex model (YawDyn) considers the coupling of blade flap motions and yaw motions which result from temporal and spatial variations in the approaching wind speed. The new methods are unique in that they simultaneously model the effects of skewed wake aerodynamics and blade stall. Both of these effects must be considered if yaw behavior is to be adequately understood. The models are validated by comparison with other prediction techniques, wind tunnel tests and full-scale atmospheric tests. In all cases the models are shown to give excellent qualitative agreement and reasonable quantitative agreement. It is concluded that the new models represent a significant improvement in the methods available to the wind turbine designer for understanding yaw loads and motions.


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