Time Of Anthesis Research Articles

Expression of ogu cytoplasmic male sterility in cybrids of Brassica napus

A light and electron microscopic investigation revealed that ogu cytoplasmic male sterility (CMS) in cybrids of Brassica napus is primarily a deficiency of the tapetum and clearly time and site specific. Three patterns of ogu CMS were found, and specific conclusions drawn. First, the partially male fertile cybrid 23 was highly variable. It sometimes produced heterogeneous stamens with an endothecium formed exclusively around the fertile locules, thus delineating each microsporangium as a functional unit. The second type, including cybrids 27, 58 and 85, on the contrary, was stable and completely male sterile. In the four locules of normal length, microspores were observed to die at the vacuolate polarized stage while the tapetum disappeared prematurely through excessive vacuolization by the end of meiosis followed by a rapid autolysis during the tetrad or early free microspore stage. The subepidermal layer of the locule wall failed to form characteristic thickenings. The male-sterile stamens were completely indehiscent. At the time of anthesis they contained only collapsed empty exines adhering to each other. These cybrids, 27, 58 and 85, were closest to the ogu CMS trait of radish and seemed to be the best suited for further use in plant breeding. The third pattern was found in cybrids 77 and 118, which besides showing abortion of the microsporangia also showed a feminization of the stamens. We suggest that this feminization might be due to an alloplasmic situation associating Brassica napus nuclear genes with the mitochondrial DNA of radish.

Male and Female Plant Selection in the Cultivation of Hemp, and Variations in Fossil Cannabis Pollen Representation

Historically, hemp has been an important economic crop, yet in the absence of deposited achenes or fibres, it is difficult to infer local hemp cultivation and/or on-site retting from variations in the values for Cannabis saliva pollen. From work in Finland, it has been suggested that lower Cannabis pollen percentages in some areas may be due to the practice of removing male hemp plants while weeding, and leaving the female plants which were apparently preferred for their fibre-producing qualities. In other geographical areas, there was no sexual selection of plants, thus enabling the pollen from male plants to be introduced more abundantly into retting pools. In this paper, the bases of this supposition arc questioned, and it is suggested that in some areas, differences in the timing of anthesis and cropping/retting may explain some of the percentage variations observed in the pollen record.

The Shuberts of Broadway: A History Drawn from the Collections of the Shubert Archive

Shubert brothers - Sam, Lee and J.J. - were the leading American theatrical producers in the first half of the 20th century. Owning or controlling 104 theatres and with assets exceeding US $70 million, their empire was responsible for some of the greatest hits of the period, ranging from the operettas Blossom Time and The Student Prince to La Belle Paree with Al Jolson and The Passing Shows, which featured George Jessel and Fred Astaire. However, relations between the brothers were not always cordial, and their dealings were ultimately the subject of a government inquiry. Drawing on the newly created Shubert Archive, this biography attempts to recreate the lives of the brothers who dominated New York's Broadway for five decades.

Regulation of Spikelet Development in Rice by Hormones

Four indica rice varieties belonging to two maturity groups were cultivated in medium irrigated land during the wet season of 1989. In all varieties, the primary branches of the panicle developed basipetally. Poor development of spikelets on the basal branches resulted in a high percentage (50-60%) of degeneration and sterility and, consequently, grain yield was poor. Application of gibberellic acid (GA3) and kinetin (6-furfuryl amino purine) improved development and grain yield on all branches. The treatments were more effective on the proximal branches and reduced the existing gradient in growth, development and yield between the distal and proximal branches. In contrast to this, 3-indole acetic acid (IAA) treatment increased spikelet growth and development in the distal branches, but suppressed them in the proximal branches thus increasing the heterogeneity in primary branch growth and development. The soluble carbohydrate and amino acid content per unit dry weight of the primary branches increased at the time of anthesis following the application of growth regulators. The assimilate level declined rapidly at the post-anthesis stage. Associated with the depressed growth and development in the lower branches of the panicle by IAA treatment, was a significantly higher level of assimilates in these branches in the post-anthesis period. The physiological mechanism of spikelet growth regulation is discussed.

Effect of timing of hand thinning on the cropping potential of Red Fuji apple trees

In a hand-thinning trial of 6-year-old Red Fuji apple trees on seedling rootstocks at the Grove Research Station in southern Tasmania, unthinned controls were compared with trees that were hand-thinned between full bloom and 56 days after full bloom. Trees were thinned to about 200 flowers or fruit per tree. The response of fruit size and weight to later thinning was negative and linear (R2=0.72). This regression was not significantly affected if adjusted for the varying fruit crop per tree. It is concluded that in Australia, Red Fuji is capable of producing larger fruit at higher crop loads than either Red Delicious or Golden Delicious and that thinning at blossom produces much larger fruit than later thinning. Because of the strong correlation between Red Fuji fruit size or weight and time of thinning, we conclude that it is preferable to thin at blossom time.

The influence of shading on yield of glasshouse tomatoes

The proportion of solar radiation incident on plants of four tomato cultivars grown as long-season, layered crops in heated glasshouse compartments was reduced by either 6.4% (light shade) or 23.4% (heavy shade); all other environmental variables were kept the same. The two shade treatments reduced the total fresh weight yield of fruit by 7.5 and 19.9% and the estimated total above-ground biomass by 6.2 and 16.5%, respectively.Over the first 14 weeks of harvest (February to May), yield was accumulated in direct proportion to solar radiation receipt and, regardless of treatment, 2.01 kg fresh weight of fruit were harvested for every 100 MJ of solar radiation incident on the crops from the onset of harvest. Later, the net incident solar radiation was apparently used more efficiently, especially under heavy shade. Furthermore, from February to May, the yield produced in each successive two-week period was proportional to the solar radiation incident on the crop in the preceding 10 weeks; the average duration of fruit development.Fruit number per truss was positively correlated with solar radiation receipt, most noticeably when less than 1.5 MJ m−2 d−l was received around the time of first anthesis of a truss. The duration of fruit development was unaffected by shade but was influenced by the position of the truss on the plant and of the fruit on the truss. In general, shade reduced average fruit size and so reduced the proportion of fruit in the larger size grades. Heavy shade also reduced the incidence of uneven ripening in summer and so increased the proportion, but not the total weight, of Class I fruit. There were differences between cultivars but no significant interactions between cultivars and treatments. The results stress the need to maximize light transmission in glasshouses, especially when considering the use of energy-saving measures.

Morphological stages and storage protein accumulation in developing alfalfa (Medicago sativa L.) seeds

AbstractIdentification of discrete stages during embryogenesis is important for the consistent and repeatable selection of seeds having similar developmental characteristics. A timetable for staging developing seeds of alfalfa (Medicago sativa L.) has been developed. Morphological characteristics, fresh and dry weights, SDSpolyacrylamide gel electrophoretic protein patterns and total protein content were recorded at various times between fertilization and 36 d after pollination (maturity), stages I–IX. A full complement of storage proteins (2S, 7S, 11S) is synthesized in both developing cotyledons and radicles. Low-salt soluble (S1) and high-salt soluble (S2) storage proteins first appear during embryo elongation. The proportional amounts of some S1 storage proteins change during alfalfa seed development. Markers are thus provided as uniform reference points for staging from the time of anthesis to seed shedding.

Testing the influence of night length on the anthesis of staminate flowers of Halophila engelmannii aschers. (Hydrocharitaceae)

Staminate flowers of Halophila engelmannii Aschers. Studied under varied night lengths had the same pattern of bud opening. During nights of either 4 1/2 or 6 h duration, the staminate flowers opened and released pollen during a 9 1/2-h light period that extended from the commencement of light at 06:00 h until mid-afternoon, 15:30 h. Flowers that had not opened by 15:30 h and that were subsequently monitored in light from 15:30 h until the time of darkness at either 24:00 or 01:30 h did not reach anthesis until the following light period. Although a previous study using 9-h nights had indicated that night length was a possible determinant of the timing of anthesis, the present study suggests that bud opening is initiated by the onset of light and that subsequently buds continue to open during a 9 1/2-h period.

ELONGATION OF LILIUM LONGIFLORUM BUDS AND PEDICELS IS LOCALIZED AT THE BUD BASE REGION

Success in the production of seasonal flowering plants requires adequate knowledge of plant growth patterns and rates. In Easter lilies, pedicel growth is one the components of final plant height. Flower bud growth rates are important from the standpoint of timing of anthesis. To learn more about the localization of growth in Easter lily flower buds and pedicels, we conducted a time course experiment. Buds and pedicels were marked at 1.2 mm intervals using an inked bolt. Distances between ink marks were determined at 3 day intervals. Results indicate that 30 mm flower buds elongate almost exclusively from basal regions of the bud. The basal 1.2 mm segment elongated 16 mm in 20 days, while the apical 1.2 mm segment elongated 0.75 mm in the same period. Larger buds (initially 90 mm) gave similar results, although bud tip growth rate increased to some degree just prior to flowering. Pedicel elongation occurred almost exclusively at the apical end of the pedicel, adjacent to the region of greatest bud growth.

Effect of Floral Morphology and Temperature on Pollen Receipt and Removal in Ipomoea Trichocarpa

In Gainesville, Florida, the coastal morning glory Ipomoea trichocarpa varies considerably in flower size, shape, and stigma—anther separation. I studied some of the causes and reproductive consequences of this variation by exploring its effect on pollen receipt and removal. Variation in flower size was caused by variation within genets and, more drastically, by temperature fluctuations. While several insect taxa visited I. trichocarpa flowers, I concentrated on one hawk moth species (Enyo lugubris) and the bumble bee Bombus pennsylvanicus. Hawk moths visited the flowers from the time of anthesis until sunrise, when bumble bees arrived. Stepwise regression analyses indicated that flower morphology affected pollen deposition during single hawk moth visits, single bumble bee visits, or unlimited hawk moth and bumble bee visits. The morphological variables with strongest effects differed in each case, and could be related to the foraging technique of each pollinator. Floral morphology affected pollen removal from flowers more than it influenced pollen receipt. The morphological variables that best explained variation in the amount of pollen removed from the anthers during a single bumble bee visit differed from those influencing pollen receipt. In the field, hawk moths could potentially fully pollinate I. trichocarpa before pollen from later rising bumble bees could send tubes to ovules. However, tube growth rate increased with rising morning temperatures. Thus, ovules could potentially have been fertilized by a mixture of pollen deposited by hawk moths and by bumble bees. Furthermore, low morning temperatures excluded hawk moths entirely from I. trichocarpa pollination, by delaying anthesis. On cool mornings, flowers opened in time to receive bumble bee visits only. The effect of temperature on flower size and pollinator type, coupled with the physical interaction between flower and pollinator morphologies, determined the amount of pollen removed from and received by I. trichocarpa.

Relative Humidity and Nutrient Concentration Affect Nutrient Uptake and Growth of Begonia × hiemalis

Young plants of Begonia × hiemalis Fotsch `Schwabenland Red' were grown for 10 weeks at 60% ± 5% or 90% ± 5% relative humidity (RH) in growth rooms. Plants were watered with three nutrient solution concentrations (1, 2, and 4 mS·cm-1). Transpiration of the plants was 56% lower at the high RH level, while the concentration of the nutrient solution had less effect (10% to 20%). Plant dry weight, height, width, and leaf size were significantly higher at the higher RH. Dry weight, height, width, and leaf size of the plants were higher in the 2 mS·cm-1 than in the 1 mS·cm-1 solution when grown at high RH, but not at a lower RH. A further increase of the nutrient solution concentration either had no effect or was detrimental. The higher RH decreased the concentration of N, P, and K in leaves and stems of plants, but an increase in the concentration of the nutrient solution increased the concentration of N, P, K, and Ca in both leaves and stems. At termination of the experiment, the number of flowers and flower buds and percent of flowering plants was higher at 90% RH than at 60% RH. These values also were higher at the higher nutrient solution concentrations. Time of anthesis was not affected.

Functional Interactions among Traits that Determine Reproductive Success in a Native Annual Plant

We grew cocklebur, Xanthium strumarium L. (Compositae), in an experimental garden and monitored a variety of morphological, physiological, and phenological traits known to have a significant influence on plant productive success. We used a hierarchical series of multiple regression analyses to generate a path diagram explaining the interacting contributions of individual traits to the numbers and size of fruits produced by individual plants. Fruit production was strongly positively correlated with plant vegetative biomass, and fruit size was negatively correlated with the total number of fruits produced. Although larger plants produced more fruit, there was also a significant direct effect of the timing of anthesis on total fruit numbers; plants in this determinate species that flowered later produced more fruit. The influence of all other traits on reproductive success was indirect through their influence on plant size. Plants with higher water—use efficiencies early in the season produced leaves more quickly, while plants which emerged earlier grew more rapidly in height. These faster growing plants had a higher vegetative biomass and consequently a greater reproductive success. Latter emergence also had a direct positive influence on plant size, demonstrating that a single trait can have significant but counteracting influences on final reproductive success. These results demonstrate the utility of an inductive approach in analyzing the actual functional pathways by which diverse traits influence growth and reproduction at the whole plant level.

The effect of inter-fruit competition, type of fruiting lateral and time of anthesis on the fruit growth of kiwifruit(Actinidia deliciosa)

The final fruit size of kiwifruit was dependent on seed number, but fruit with few seeds were proportionally smaller if in close proximity to fruit with many seeds. Fruit on the same lateral with equal seed numbers developed to similar final fruit sizes. The final size of a fruit was also partly determined by pre-anthesis factors. Late opening flowers tended to produce small fruit. A predominance (74.3%) of late flowers were found on short (terminating) laterals, while 85.4% of early flowers were carried on long (non-terminating) laterals. Differences in mean fruit size at harvest between fruit developing from early or late flowers on uniform, short laterals were as much as 31 g. This was equivalent to a reduction of about 2 g per day as anthesis was delayed. This difference was independent of fruit seed number, but a significant difference between the size of the ovary of early and late flowers was present at the beginning of fruit development. In addition, fruit produced on long laterals were bigger (10...

キュウリ果実の着果•肥大期における光合成産物の転流•分配に及ぼすベンジル•アデニンの影響

Studies were carried out to clarify the effects of benzyl adenine on translocation and distribution of 14C-assimilates in relation to fruit setting and development in cucumber plants.Fruit setting and early fruit development were accelerated by pollination. Furthermore, parthenocarpic fruit setting was induced by benzyl adenine. Great changes occurred on the RSS (Relative Strength as a Sink) values before and after anthesis.The RSS value was high before anthesis and it decreased rapidly on the day of anthesis. After pollination or treatment by benzyl adenine the RSS increased rapidly again.The changes in auxin content by pollination and treatment by benzyl adenine were almostly similar in pattern to the changes of the RSS. Therefore, it seems that the effect of benzyl adenine is related to the inhibition of decrease of auxin content.14C-benzyl adenine moved to the acropetal area of fruit and accounted for more than 10 per cent of total amount of 14C supplied to fruit within 24h.There were physiological changes in the flower buds before and after anthesis. It is likely that the flower bud acts as a growing point, like a leafy bud, before anthesis. However, from the time of anthesis until fruit setting the flower bud suspends physiological activity and after fruit setting the flower bud probably changes physiological phase and the fruit develops rapidly.

Cell and Tissue Damage Associated with Pistillate Flower Abscission of Persian Walnut

Abstract Pistillate flowers from walnut trees having > 80% pistillate flower abscission (PFA) were examined from the time of anthesis until shortly before abscission. In addition to normally developing flowers, two types of abortive flowers were found. One abnormal flower type, seen in only two cases, lacked a developed embryo sac and had cellular degeneration in the nucellus. The second type of damaged flowers, which were more commonly observed, had apparently normal development of the nucelli and embryo sacs, but cell and tissue necrosis became evident beginning at the tip of the stigma, in the integuments, and throughout the placental evaginations. No cell or tissue damage was observed until after ovary growth in these flowers had stopped. We conclude that this second type of damage is associated with PFA.

Effects of applied nitrogen upon aspects of nitrogen metabolism and transport in developing nodulated winged bean plants

Nodulated winged bean [Psophocarpus tetragonolobus (L.) DC., cv. UPS 122] were grown under constant environmental conditions and supplied with mineral nutrient solution in which nitrogen was absent or was present as nitrate (12 mg N week‐1 plant‐1).Nitrate treatment dramatically promoted plant growth, increased fruit weight 1.6 fold, was necessary for tuberisation and enhanced nodulation. The in vitro accumulation of 14C into asparagine and aspartate components of excised nodules supplied with exogenous 14CO2 and [14C]‐D‐glucose was greater for nitrate‐treated plants, whilst accumulation into ureides was reduced by nitrate treatment. Levels of amino acids in xylem sap were greater for plants supplied with a complete nutrient solution, than those grown without applied nitrate, particularly for asparagine, glutamine and proline. Xylem ureide levels were greater for plants grown in the absence of supplementary nitrate.Nitrogen accumulated in leaf, stem and petiole, and root nodule tissues for utilisation during fruit development; peak nitrogen levels and time of anthesis were retarded for plants grown without applied nitrate. The shoot ureide content increased during fruiting, coincident with decreases in the total nitrogen content, indicating that ureide pools are not utilised during the early reproductive phase. However ureide reserves, particularly allantoin, were utilised during the later stages of pod fill.Enzyme activity which metabolised asparagine was found throughout the plant and was identified as K+‐dependent asparaginase (EC 3.5.1.1) and an aminotransferase. Apart from temporal differences in developmental profiles of enzyme activity, the activity of these enzymes and of allantoinase (EC 3.5.2.5) in developing tissues were similar for both treatments. The main differences were greater asparaginase and asparagine:pyruvate aminotransferase activities in root tissues and fruit of nitrate‐supplied plants; allantoinase activity in the primary roots of plants grown without nitrate decreased during development, whilst activity in developing tubers (nitrate‐supplied plants) increased.

Sunflower Genotype Response to Photoperiod and Temperature in Field Environments

AbstractSunflower (Helianthus annuus L.) is cultivated over a wide range of photoperiod and temperature conditions. The objective of this research was to determine the response of 16 diverse sunflower genotypes to varying photoperiod and temperature. Field research sites were at five locations including Argentina, Alaska, and Hawaii. The photoperiod (daylength + twilight hours) at vegetative emergence (VE) for most sites, except Hawaii and Alaska, ranged from 14.5 to 16.2 h. Within this range there was no evidence that photoperiod affected the time from VE to bud visible stage (R1). Instead, differences in temperature at various sites were responsible for differing rates of development. However, the short photoperiods at VE at Hawaii (11.2 h) decreased development rate and long photoperiods at Alaska (24 h) increased development rate dramatically. A nonparametric method was applied to rank the genotypes into temperature response groups. Four distinct groups resulted for the VE to R1 growth stage intervals, which were classed as very quick, quick, medium, and slow with respect to the time taken to reach R1 from VE. Four groups also resulted for the R1 to anthesis (R5.1) time period. The groups for R1 to R5.1 differed from those for VE to R1. Genotypes within these groups were dissimilar to those for VE to R1. It was concluded that models used to predict phenological development in sunflower could be based on temperature alone provided photoperiod was within the 14.5 to 16.2 h range, To predict development outside this photoperiod range would require photoperiod be included in the model.

Carbon Partitioning among Leaves, Fruits, and Seeds during Development of Phaseolus vulgaris L.

Development of vegetative and floral buds was found to be a key factor in establishing the way carbon is distributed among growing leaves and fruits in Phaseolus vulgaris L. plants. Leaves emerged principally during a period 14 to 32 days after planting while flowers were produced during a 10- to 12-day period near the end of leaf emergence. Timing of anthesis established the sigmoidal time course for dry weight accumulated by the composite of all fruits on the plant. During the first 12 days following anthesis, fruit growth mainly consisted of elongation and dry weight accumulation by the pod wall. Thereafter, seed dry weight increased for about 1 week, decreased markedly for several days, and then increased again over the next 2 weeks. Accumulation of imported carbon in individual seeds, measured by steady-state labeling, confirmed the time course for dry weight accumulation observed during seed development. Seed respiration rate initially increased rapidly along with dry weight and then remained nearly steady until seed maturation. A number of developmental events described in the literature coincided with the different phases of diauxic growth. The results demonstrated the feasibility of relating current rates of carbon import in individual seeds measured with tracer (14)C to the rates of conversion of imported sucrose and use of the products for specific developmental processes. The resulting data are useful for evaluating the roles of conversion and utilization of imported sucrose in regulating import by developing seeds.

VARIATION AMONG POPULATIONS OF XANTHIUM STRUMARIUM (COMPOSITAE) FROM NATURAL AND RUDERAL HABITATS

We assessed the mechanisms underlying the ability of cocklebur to spread from its natural riverside habitats and establish weedy populations in urban waste areas. We collected fruits from plants growing in natural and urban ruderal habitats and planted 2 maternal families from each of 9 habitat populations in 3 experimental gardens. The gardens were all in full sunlight but differed in the availability of water and nutrient resources. Plant performance in the gardens was measured by numbers and size of fruits produced. Traits known to be associated with cocklebur reproductive success were also measured: times to emergence and anthesis, photosynthetic capacity, mean stomatal conductance, relative growth rate, and biomass allocation to leaves and stems.Although there were significant differences among populations in the tradeoff between rate of growth in height and timing of anthesis, these population differences were not associated with habitat. Apart from a tendency to produce larger fruits in ruderal populations, there were no detectable differences in the characteristics of plants from natural vs. ruderal habitats. Plants from both habitats did have substantial and significant plastic responses to growth environment. In the three experimental gardens, fruit numbers increased with resource availability but fruit size did not differ significantly. As resource availability increased, plants from both habitats sustained growth longer and became more branchy. Canonical discriminant analysis of all the somatic and reproductive traits together supported the idea that natural and ruderal populations do differ in their overall plastic response to resource availability. The subtly different plastic responses of plants from the two habitats do not arise by substantial adjustments in a few dominant traits, but instead by relatively minor adjustments in a host of functionally interrelated phenological, morphological, and physiological traits. It is these small but coordinated differences in the plastic responses of many traits that appear to differentiate cocklebur from natural vs. weedy urban habitats.

Respiration and Dry Matter Accumulation Around the Time of Anthesis in Field Stands of Winter Wheat (Triticum aestivum)

Respiration and Dry Matter Accumulation Around the Time of Anthesis in Field Stands of Winter Wheat (Triticum aestivum)