Day Of Anthesis Research Articles

KANDUNGAN AUKSIN (ASAM 3-INDOL ASETAT) PADA TAHAP PERKEMBANGAN BUAH KACANG TANAH (Arachis hypogaea (L.) Merr.)

Auxin has an important role to control both of the growth and tropism of gynophore and the development of fruit and embryo of peanut (Arachis hypogaea (L). Merr.). The experiment was carried out to examine the contents of auxin during peanut development, i.e. at the time of anthesis (day 0), at day 4, 7, 10, 15, 18, 23, and 31 after anthesis, using High Performance Liquid Chromatography (HPLC) with fluorescence detector method. Between the day of anthesis to the day 31 after anthesis, the auxin contents changed according to fruit development stage. The free auxin contents in the developed fruit (entering the soil) were higher than undeveloped fruit (not entering the soil), while the bound auxin content in the developed fruit were lower than undeveloped fruit. The lowest free auxin contents was found at the time of anthesis, then increased drastically when the gynophore grew fast and in the beginning of embryo development stage (day 7). Between the day 7 to the day 15 after anthesis, the free auxin contents were decreased. In the development fruit, the free auxin contents increased when the fruit begin to grow (day 15-18), then decreased until the seed reached its full size (day 31). In the undeveloped fruit, the free auxin contents decreased at day 7 to day 31. The bound auxin contents in the developed fruit decreased until the day 18, and increased gradually until day 31. In the undeveloped fruit, the bound auxin contents decreased at day 15 and afterward.

HOW TO BE SWEET? EXTRAFLORAL NECTAR ALLOCATION BY GOSSYPIUM HIRSUTUM FITS OPTIMAL DEFENSE THEORY PREDICTIONS

Plants employ nectar for two distinct functions. Floral nectar has traditionally been viewed in the context of pollination. Extrafloral nectar on the other hand, can act as an indirect defense, allowing the plant to recruit predators and parasitoids. Whereas this makes for a clear-cut categorization, in reality the functions may not be so discrete. Extrafloral nectar may serve a role in pollination, while floral nectar can be utilized by predators and parasitoids and thus can contribute to plant defense. Here we use the optimal defense theory to generate predictions with respect to allocation patterns of defensive nectar. These predictions are then tested using novel data on the production patterns of bracteal and foliar nectar in cotton, Gossypium hirsutum. Bracteal nectar production shows a distinct peak on the day of anthesis, followed by a prolonged secretion during fruit maturation. This suggests that bracteal nectaries function in pollination as well as defense. Constitutive nectar production at the bracteal nectaries exceeds foliar nectar secretion by a factor of between 80 and 110. Whereas nectar production at foliar nectaries is induced following herbivore damage to leaves, bracteal nectar production is not induced in response to fruit damage and even decreases when the fruiting structure is subjected to herbivory. This shows that both an inducible and a constitutive variant of an indirect defense can occur within one plant species. This pattern of nectar allocation fits the optimal defense theory, which predicts high levels of constitutive defenses in valuable tissues such as fruits and induced defenses in less valuable tissues such as leaves. This result lends support to the interpretation that indirect defense has been a selective force in the evolution of bracteal nectaries. Although optimal defense theory has described direct defense allocation solely in terms of probability of attack and value of the plant structure, we argue that herbivore accessibility is an additional factor shaping the allocation of indirect defenses.

Cloning of fatty acid biosynthetic genes β-ketoacyl CoA synthase, fatty acid elongase, stearoyl-ACP desaturase, and fatty acid desaturase and analysis of expression in the early developmental stages of flax ( Linum usitatissimum L.) seeds

Flaxseed products in the form of nutraceuticals and health foods are now widespread. This success is mainly attributable to their essential fatty acids. To identify the key genes involved in fatty acids biosynthesis, a cDNA library made from flax bolls collected at 12 days after anthesis (12 DAA) was constructed and screened for β-ketoacyl CoA synthase (KAS), fatty acid elongase (FAE), stearoyl-ACP desaturase (SAD), and fatty acid desaturase (FAD). Condensing enzymes (KAS and FAE) were shown to be represented in higher numbers in the library as compared to the desaturases (SAD and FAD). Multiple sequence alignment showed that the FAD sequence (linFAD) reported herein was an endoplasmic reticulum microsomal fatty acid desaturase, whereas linKAS appeared to be related to the very long fatty acid condensing protein suggesting that other members of these two gene families may be present in flax. Furthermore, linKAS and linFAD were shown to be expressed as early as the day of anthesis and fatty acid profiling at anthesis and at 2 DAA revealed high content of palmitate (16:0), linoleate (18:2), and linolenate (18:3) as compared to stearate (18:0) and oleate (18:1). This result suggests a high activity of condensing enzymes and delta 12 and delta 15 desaturases at these early developmental stages. This report is the first dealing with flax genomics linking fatty acid profiling and lipid biosynthetic pathway.

Effects of brassinolide on the physiological properties of litchi pericarp ( Litchi chinensis cv. nuomoci)

‘Litchi trees ( Litchi chinensis cv. nuomoci) were sprayed with 0.5 mg/l (T1), 0.75 mg/l (T2), 1.0 mg/l (T3) of brassinolide and with water (CK) as the control group before anthesis. The enzyme activities of pectin methyesterase (PME), polygalacturonase (PG), cellulase (CX) and the content of water-soluble pectin, protopectin and calcium in the fruit pericarp were studied in order to investigate the effect of brassinolide on litchi pericarp during its development. Content of water-soluble pectin remained at a higher concentration during early stages of development of treated fruit compared to control fruit. Protopectin content increased during fruit development and reached a peak after 58 days of anthesis. PME and PG activities both increased and showed the same trend under T1, T2 and T3 as the concentrations of pectin and protopectin. Calcium concentration of fruit pericarp was higher in treated fruit than control fruit and showed significant dosage response. CX activity was inhibited by brassinolide treatment. The brassinolide reduced fruit cracking compared to the control. The results showed that brassinolide sprayed before anthesis may play an important role in increasing the commercial value of litchi fruits.

Pollination ecology and pollination system of Impatiens reptans (Balsaminaceae) endemic to China.

China is one of the centres of geographical distribution of Impatiens L. Studies of the pollination ecology of this genus in China have, until now, been unreported. Impatiens reptans, a species endemic to China, was studied. The aims were to examine the pollination ecology and pollination system of this species, to compare its pollination ecology with other Impatiens species growing in Sumatra and Japan, and to discuss possible reasons for its limited distribution. The pollination ecology of I. reptans was studied by carrying out continuous observations within three naturally growing populations. Its pollination system was studied using different pollination methods, marking and counting pollen grains, assessing pollen viability and observing pollinator behaviour. The flowering phase of the protandrous I. reptans lasted for 89 d. The life span of an individual flower was 3.6 d. Primary pollinators were honey-bees and bumble-bees. Secondary pollinators were diurnal hawk moths and butterflies. Bombus briviceps and Bombus sp. were nectar gatherers. The mean nectar sugar concentration was 29.5 %, and the mean value of sucrose/glucose + fructose was 0.82. The proportion of seed set ranged from 0.857 to 0.873. Distances that seeds were ejected ranged from 0.58 to 1.17 m. Percentage seed germination under controlled conditions was 23.1. Pollen viability was highest on the day of anthesis and thereafter decreased. Ratios of pollen : ovules ranged from 958.8 to 970.6. Impatiens reptans reproduces by means of cross-pollination. Its dependence on a specialized habitat, a narrow environmental niche, a low percentage of seed germination, and habitat loss could be reasons for its limited distribution and endemism.

Daily Blooming Pattern and Pollination by Syrphids in Sisyrinchium vaginatum (Iridaceae) in Southeastern Brazil

FREITAS, L. AND M. SAZIMA (Departamento de Botanica, Caixa Postal 6109, Universidade Estadual de Campinas, 13083-970 Campinas, Sao Paulo, Brasil). Daily blooming pattern and pollination by syrphids in Sisyrinchium vaginatum (Iridaceae) in southeastern Brazil. J. Torrey Bot. Soc. 130: 55-61. 2003.-Flowers of Sisyrinchium are regarded as fugacious and bee-pollinated. We report a species of this genus bearing flowers that last 1 to 4 days, and are mainly pollinated by hoverflies. Floral biology, daily blooming pattern, floral longevity, and frequency and behavior of pollinators of Sisyrinchium vaginatum were studied in a high-altitude grassland in the Serra da Bocaina, southeastern Brazil. Anthesis starts between 10:00 and 16:30 h, but most flowers open in the middle of the day. Flowers open and close every day, or may remain closed on their second day of anthesis, to then re-open the subsequent day. The regulation of flower longevity and blooming pattern seems to be endogenous, but climatic conditions and pollinator activity may also be involved. As a floral reward, the yellow, dish-shaped flowers only offer pollen. Although small bees were reported as the main or exclusive pollinators for other areas, syrphids were the main pollinators of S. vaginatum in the Serra da Bocaina. For this population, the flowering peak occurred during the winter, while for populations of other areas it took place during the summer. Since, in winter, the diversity and number of small bees is extremely reduced in those highaltitude grasslands, the syrphid-pollination in the Bocaina's population is probably linked to its flowering peak in that season.

Embryology of two threatened species of Pachycladon (Brassicaceae)

Ovule development and embryogenesis are described for Pachycladon exilis and P. cheesemanii using thin sectioning of resin‐embedded tissue. The structures of megasporogenesis and embryogenesis in these two species of Pachycladon were similar to those described for Arabidopsis thaliana. There was, however, a significant difference in the timing of events, with an extended delay apparent in Pachycladon between anther dehiscence and the first cell divisions of the embryo and endosperm. Initial endosperm development in the two Pachycladon species was of the free nuclear type, followed by cellularisation in a manner similar to that seen in Arabidopsis. Within one day of anthesis a chalazal proliferating tissue mass developed adjacent to the chalazal pole of the embryo sac. However, free nuclear division of endosperm nuclei was not observed until 7 days after anther dehiscence. The stages of embryogenesis for the two Pachycladon species were approximately correspondent in time, but the final silique length and rate of silique elongation of P. cheesemanii was greater than for P. exilis. The siliques of P. cheesemanii also took at least an extra 7 days to desiccate at maturity.

Studies on floral biology of Ixora agasthyamalayana Sivadasan & Mohanan - a rare southern Western Ghats endemic

Ixora agasthyamalayana is a rare and endemic taxon of southern Western Ghats of Kerala. It flowers throughout the year under the climatic conditions of Agasthyamala and the peak during January. The floral biology of this plant was studied. Anthesis occurred between 0600 and 1300hr with its peak at 0700hr. Anther dehiscence was observed between 0700 and 1300hr with a peak at 1000hr. The maximum receptivity of stigma was found on the day of anthesis. Pollen grains were round, light pink in colour and 32.24µm in diameter.

Pollination and CPPU Treatment Increase Endogenous IAA and Decrease Endogenous ABA in Muskmelons during Early Development

An investigation was conducted to determine how pollination and CPPU treatment influence endogenous IAA and ABA content in netted muskmelon [Cucumis melo L. (Reticulatus Group) `Crest Earl's'], and to clarify their roles in fruit set and development in relation to these endogenous plant hormones. CPPU treatment at anthesis significantly increased the fresh weight of ovaries, whether the flowers were pollinated or not, but from 6 days after anthesis (DAA) the growth rate in the nonpollinated + CPPU treatment tended to be lower than the growth rates in the pollination treatment plots. Ovaries of nonpollinated flowers not treated with CPPU failed to grow and turned brown within 4 DAA. IAA content in the placenta of fruit from pollinated flowers increased rapidly from the day of anthesis to 2 DAA and remained at relatively high levels. IAA content in the placenta of parthenocarpic fruit induced to develop by CPPU treatment was lower than that of fruit from pollinated flowers but the pattern was almost the same as that in fruit of pollinated flowers. Conversely, IAA content in the placenta of fruit from nonpollinated flowers not treated with CPPU decreased sharply after anthesis. IAA content in the mesocarp of CPPU-treated fruit, whether or not the flowers were pollinated, increased significantly from the day of anthesis to 2 DAA, then decreased to almost the same level as that of the pollination-only treatment by 10 DAA, while the IAA content of nonpollinated CPPU-treated fruit declined even further. IAA content in the mesocarp of fruit from nonpollinated flowers not treated with CPPU decreased sharply. ABA contents in both the placenta and mesocarp of muskmelon that would set decreased after anthesis while the ABA content of muskmelon that would not set increased rapidly. Results suggest that pollination and CPPU treatment increased endogenous IAA content and decreased endogenous ABA content to promote the set and growth of fruit during early development. Chemical names used: [1-(2-chloro-4-pyridyl)-3-phenylurea] (CPPU); indole-3-acetic acid (IAA); abscisic acid (ABA).

Relationships Between Blueberry Flower Age, Pollination, and Conidial Infection byMonilinia vaccinii-corymbosi

ABSTRACT Monilinia vaccinii-corymbosi infects open blueberry flowers via the gynoecial pathway, leading to mummification of the developing fruit. To determine the effect of flower age on infection, stigmata were inoculated with conidia of M. vaccinii-corymbosi between 0 and 5 days after anthesis, fungal growth rates through the stylar canal were measured in detached flowers in the laboratory, and fruit disease incidence was determined in plants grown in the greenhouse. Hyphal growth rates were greatest in flowers inoculated on the day of anthesis, declined linearly with increasing flower age at inoculation (r = 0.921; P < 0.0001; n = 12), and were unaffected by the presence or absence of pollen applied at the time of inoculation. In greenhouse-grown plants, the percentage of infected fruit decreased exponentially with increasing flower age at inoculation (R = 0.878; P = 0.0057; n = 10), with disease incidence ranging from 76.4% for flowers inoculated on the day of anthesis to 15.5% for those inoculated 4 days later. Fruit disease incidence in the greenhouse was linearly correlated with hyphal growth rates in detached flowers (r = 0.985; P < 0.0001; n = 9), justifying the use of detached flowers when investigating gynoecial infection by M. vaccinii-corymbosi. In separate experiments, the effects of timing and sequence of pollination and inoculation on hyphal growth rates through the stylar canal and on disease incidence were investigated. Application of pollen to detached flowers 1 or 2 days before inoculation reduced hyphal growth rates by between 14.0 and 42.9% compared with flowers that received pollen and conidia simultaneously. Similarly, reductions in fruit disease incidence by between 9.5 and 18.3% were observed on greenhouse-grown plants for pollination-to-inoculation intervals ranging from 1 to 4 days. These results document that newly opened flowers are most susceptible to infection by M. vaccinii-corymbosi and that fruit disease incidence is reduced if pollination occurs at least 1 day before inoculation. Strategies that lead to early pollination of newly opened flowers may be useful for managing mummy berry disease in the field.

Environmental Control of Moisture Content and Viability in Schlumbergera truncata (Cactaceae) Pollen

The objective of this study was to determine the effects of temperature, relative humidity (RH), and storage duration on moisture content and viability of Schlumbergera truncata (Haworth) Moran (Thanksgiving cactus) pollen. Pollen viability was assayed by the fluorochromatic reaction (FCR) test, percentage fruit set, and numbers of viable seeds per fruit. Pollen moisture content was ≈38% at anthesis but decreased to ≈12% by 1 day after anthesis and remained low (10% to 12%) until flowers senesced. Pollen viability was 85% on the day of anthesis, remained at ≈80% from 1 to 3 days after anthesis, and decreased to ≈65% when flowers began to senesce. When pollen was stored for 4 days at 21 °C, moisture content decreased to 1% for pollen stored at 1% RH but increased to 33% for pollen kept at 100% RH. Fruit and seed yields obtained with pollen stored for 4 days at 21 °C and 15%, 28%, or 52% RH did not differ significantly from those obtained with fresh pollen. Pollen stored for 4 days at 21 °C and 1%, 68%, or 90% RH produced fewer fruit and seeds than fresh pollen. Fruit and seed yields obtained with pollen stored 20 days at 21 °C and 15% or 28% RH were similar to yields obtained with fresh pollen. Pollen with ≤23% moisture content that was stored at -18 °C for ≥24 hours retained its original viability (≈85%) whereas pollen with a high (32% to 34%) moisture content exhibited low (≈22%) viability after storage at -18 °C for ≥24 hours. Pollen stored for 140 days at 4 or -18 °C and 13% to 51% RH yielded as many viable seeds per fruit as fresh pollen. Although S. truncata pollen is tricellular, it tolerates desiccation to a low (4%) moisture content and can be stored at temperatures below 0 °C.

Analysis of genes preferentially expressed in early stage of pollinated and parthenocarpic fruit in eggplant

Summary To isolate genes preferentially expressed at early stages of fruits in eggplant (Solanum melongena L., var. Senryo No. 2), subtractive hybridization was used on cDNAs from pollinated fruits and poly(A)+RNA from unpollinated fruits at 3 days after anthesis. In this way, 8 cDNA clones were isolated from a cDNA library constructed from pollinated fruits at 3 days after anthesis, and were designated EEF13, 20, 22, 26, 38, 45, 48, and 53, respectively. Expression patterns of EEF genes in pollinated fruit were similar to those in 4-chlorophenoxyacetic acid (4-CPA)-treated fruit by Northern blot analyses. During development of pollinated and 4-CPA-treated fruit, the transcription patterns of EEF genes were classified into three types. EEF20 and EEF38 genes whose products are highly similar to histones, were expressed abundantly on the day of anthesis and continued to be expressed during the early stages of fruit development (Type 1). Transcription of five genes was at higher level from 2 to 4 days after anthesis (Type 2), and the encoded products of EEF22 and EEF26, showed high similarity with calreticulin and polyphenol oxidase, respectively. Another gene, EEF48 (Type 3), showed high and continuous expression from 2 to 20 days after anthesis and was almost restricted to fruits. Deduced amino acid sequence of EEF48 showed high similarity with a cell wall protein.

Developmental aberrations in seeds of boron deficient sunflower and recovery

Sunflower (Helianthus annuus L.) cv. Modern grown in refined sand at deficient (0.033 mg L‐1) boron (B) developed visible symptoms of low B accompanied by marked depression in growth, dry matter, tissue B, flower head size, and seed weight. The B deficient seeds showed a marked decrease in non‐reducing sugars and contents of oil and starch whereas in leaves reducing sugars accumulated. Except for slight increase in leaf B and flower size, resumption of sufficient B (0.33 mg L‐1) to B deficient plants from the day of anthesis could not appreciably alter the growth, dry matter, head size and seed weight of deficient plants. Apart from this, non‐reducing sugar content in seeds increased on resupplying B to deficient plants. A significant decrease in non‐reducing sugars and starch content in B sufficient seeds by withdrawing B from the day of anthesis indicate a specific role of B in production and deposition of reserve in the seeds of sunflower.

233 Alteration of Flower Development and Fruit Growth in Summer Squash

Many summer squash hybrids initiate flowering by first producing one or more pistillate flowers before the development of any staminate flowers. These first pistillate flowers have no pollen source unless an earlier squash planting is nearby. The objectives of this study were to measure the loss in yield incurred by the absence of pollination and to determine if sex expression in squash could be altered by use of gibberellic acid (GA). `Cougar' summer squash was planted in 12 isolated plots on 13 May; four plots had adjacent rows planted on 3 May to provide pollen for the earliest developing pistillate flowers in those plots. On 28 May, 0.146 L·ha-1 of GA (ProGibb 4®) was applied to an adjacent row in four of the plots planted on 13 May. The four control plots received no treatment. At anthesis, pistillate and staminate flowers were counted daily for 10 days. The first six pistillate flowers that bloomed in each plot were identified and measured (length and diameter) on the day of anthesis, and at 4 and 7 days after anthesis. Fruit were harvested five times at 2-day intervals and data are reported on fruit ≤5.7 cm in diameter. GA had no effect on squash flowering habit. At 4 and 7 days after anthesis, fruit were smaller in plots where no pollen source was available. Early yields were higher for the first two harvests in plots where pollinators were present. A small, early planting of squash should be made to provide staminate flowers for normal growth and development of early fruit on the main summer squash crop.

Expression pattern of (+)-delta-cadinene synthase genes and biosynthesis of sesquiterpene aldehydes in plants of Gossypium arboreum L.

The cotton (+)-delta-cadinene synthase, a sesquiterpene cyclase, is encoded by a complex gene family which, based on homology, can be divided into two subfamilies: cad1-A and cad1-C. Southern blots revealed several members of the cad1-C subfamily, and a single member of the cad1-A subfamily, in the diploid Gossypium arboreum genome. One of the cad1-C genes, cad1-C3, was isolated from this species. According to reverse transcriptase-polymerase chain reaction, transcripts of both cad1-C and cad1-A genes appeared in roots from the second day post germination and in 1-d-old cotyledons, whereas the transcription levels were too low to be detected in the hypocotyls. Initially, sesquiterpene cyclase activities were found to be high in the seedlings, then dropped in aerial organs but increased in roots during development. Sesquiterpene aldehyde contents followed the same pattern. In fully developed plants, the transcripts of cad1-C were detected in stems, leaves and pericarps, as well as in the sepals and petals 3 d before anthesis, but not at the day of anthesis. In contrast, cad1-A transcripts were not detected in any of these aerial organs. The sesquiterpene aldehyde contents increased in petals but decreased in sepals after anthesis. Treatment of G. arboreum stems with a Verticillium dahliae elicitor-preparation activated cad1-A transcription, but a significant level of cad1-C transcripts was detected both before and after elicitation. In G. hirsutum cv. GL-5, a glandless cultivar, the cad1-C gene was activated by the same fungal elicitor, followed by the synthesis of the sesquiterpene cyclase, and accumulation of sesquiterpene aldehydes. The cad1 gene expression during development and in response to elicitation, as well as the spatial and temporal pattern of sesquiterpene biosynthesis, constitute a chemical defense machinery in cotton plants.

Anthesis, anther dehiscence, pistil receptivity and fruit development in the Longum group of Capsicum annuum

Little attention has been paid to the events associated with fruit production such as flowering and seed set in chilli peppers despite this species being a major horticultural crop. To address this deficit, we examined flowering phenology in the cv. Red Hot Glory, a representative of the Longum group of peppers. Measurements of bud length and width showed that these characteristics can provide an effective index of the number of days required by a bud to reach anthesis. Anthesis itself mainly occurred during the morning with a second, smaller peak of flower opening in the afternoon. Measurements made in spring and summer suggested that the daily start of anthesis is controlled by daylength. In flowers that opened before 1700 hours, anther dehiscence took place 1 h after the buds opened; in flowers that opened later, dehiscence was delayed until the following morning. This pattern of anther dehiscence suggests that this event is partially controlled by the flower’s endogenous rhythms. Controlled pollinations showed that the period of female receptivity, as judged by seed set, lasted from 5 days before anthesis to 3 days after anthesis with maximum fertility occurring on the day of anthesis. Therefore, bud pollinations are possible, and, for maximum seed set, should be made as close to the day of anthesis as possible. This study has provided baseline data that will aid the production of new, hybrid cultivars and will facilitate further studies on the factors affecting fertility in this species.

Pathway and control of sucrose import into initiating cotton fibre cells

This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999 Our aim is to unravel the mechanisms controlling fibre cell initiation from the epidermis of cotton (Gossypium hirsutum L.) ovules. We compared the development of fibres and trichomes in wild type cotton and a fibreless seed (fls) mutant, and determined the cellular pathway of sucrose transport into fibre initials on the day of anthesis. Although fibre initiation is inhibited in the fls mutant, leading to the fibreless phenotype, trichome development in other parts of the plant is normal. Confocal imaging analysis revealed that the fluorescent molecule, 5(6)-carboxyfluorescein, which is transported symplastically, moved readily from the integument phloem into initiating fibres. Plasmolysis studies showed that the fibre initials and adjacent non-initiating ovule epidermal cells have similar osmotic potential. Immunolocalisation analysis showed the absence of sucrose transporter proteins in the initiating fibre, but their abundance in the transfer cell precursors at the innermost integument. These results (i) demonstrate that fibre cell initiation is controlled by unique mechanism(s) that differ from that for normal trichome development; (ii) show a symplastic pathway of sucrose import into initiating fibres and strengthen the current opinion that sucrose synthase is likely to be the key enzyme mobilising sucrose into initiating fibres; and (iii) suggest that the initial protrusion of the fibre cells above the ovule surface is largely achieved by increased cell wall extensibility rather than higher turgor as is commonly thought.

Pollination requirements of West Indian cherry (Malpighia emarginata) and its putative pollinators, Centris bees, in NE Brazil

The pollination requirements of West Indian cherry (Malpighia emarginata DC) were investigated in NE Brazil through observations of flower morphology, floral rewards, anthesis, anther dehiscence, stigma receptivity, pollen cross and self-compatibility and proportion of fruit set. Potential insect pollinators and their foraging behaviour were also studied, and the pollination efficiency of the most frequent flower visitor, the bee Centris tarsata Smith (Anthophoridae), was assessed using single visits to flowers. It was shown that the West Indian cherry flower has a short lifespan, thus requiring pollination on the day of anthesis, when both cross- and self-pollen grains set fruit. The flower can potentially be pollinated by an array of insect visitors, but only oil-collecting bees of the genus Centris find it very attractive. Centris tarsata appeared as the main pollinator of West Indian cherry in the area studied, and farmers are advised to encourage its presence in orchards. Despite high levels of natural pollination, only 30% of flowers set fruits. It is suggested that a high proportion of abnormal ovule development may be responsible for low fruit set where pollination is satisfactory, and that West Indian cherry varieties showing a lower percentage of such abnormalities should be selected for.

Characterization of the natural chemical and osmotic environment of early wheat embryogenesis

Soluble carbohydrates, amino acids, and major inorganic ions were quantified and compared with the total osmolarity of the ovule. Most of the analyzed components increased rapidly in concentration, reaching a peak at 1 day post anthesis (DPA) and decreasing quickly 1 day later. Within this time period, the osmolarity decreased from 1.49 to 1.18 MPa. The osmolarity then increased to 1.39 MPa at 4 DPA, and yet the overall concentration of analyzed molecules decreased. At 1 DPA, inorganic ions were observed at levels that could produce a high osmolarity (1.11 MPa), followed by the carbohydrates (0.37 MPa) and amino acids (0.07 MPa). Maltose was detected in ovules only from 0 to 2 DPA. Inositol was abundant in the ovules on the day of anthesis, but decreased to non‐detectable levels after 4 DPA. This suggested that ovules allow the rapid entry of solutes into the syncytial endosperm after fertilization, but are osmotically buffered through the increase and decrease of partly identified substances. Specific gravity tests on the liquid squeezed from young endosperm sukpported this new hypothesis. Osmolarity in ovules seems only indirectly related to morphogenetic regulation mechanisms, and it may play a lesser role than the fluctuations of certain specific substances. The observed chemical changes offer insights into the rapidly varying nutritional needs of proembryos. Thus, in this research yielded a useful complex amino acid formula, derived from knowledge of the natural environment of the proembryo, and also an improved proembryo and ovule culture medium.

Characterization of the natural chemical and osmotic environment of early wheat embryogenesis

Soluble carbohydrates, amino acids, and major inorganic ions were quantified and compared with the total osmolarity of the ovule. Most of the analyzed components increased rapidly in concentration, reaching a peak at 1 day post anthesis (DPA) and decreasing quickly 1 day later. Within this time period, the osmolarity decreased from 1.49 to 1.18 MPa. The osmolarity then increased to 1.39 MPa at 4 DPA, and yet the overall concentration of analyzed molecules decreased. At 1 DPA, inorganic ions were observed at levels that could produce a high osmolarity (1.11 MPa), followed by the carbohydrates (0.37 MPa) and amino acids (0.07 MPa). Maltose was detected in ovules only from 0 to 2 DPA. Inositol was abundant in the ovules on the day of anthesis, but decreased to non-detectable levels after 4 DPA. This suggested that ovules allow the rapid entry of solutes into the syncytial endosperm after fertilization, but are osmotically buffered through the increase and decrease of partly identified substances. Specific gravity tests on the liquid squeezed from young endosperm sukpported this new hypothesis. Osmolarity in ovules seems only indirectly related to morphogenetic regulation mechanisms, and it may play a lesser role than the fluctuations of certain specific substances. The observed chemical changes offer insights into the rapidly varying nutritional needs of proembryos. Thus, in this research yielded a useful complex amino acid formula, derived from knowledge of the natural environment of the proembryo, and also an improved proembryo and ovule culture medium.