Flower Greenhouse Research Articles

Contents of ecological modelling, vol. 70

A flower model trap developed by modifying an artificial yellow chrysanthemum flower was more attractive to flower thrips than commercial yellow sticky traps. Installation of these flower model traps (20 traps per 50 m2 plot) was reported to reduce seasonal populations of Frankliniella intonsa (Trybom) (Thysanoptera: Thripidae) on strawberry flowers in greenhouses. In this study, we sought to determine if the installation of such flower model traps would reduce thrips populations in a pepper field. The traps were installed at the bottom of the plant canopy at varying densities (0, 5, 10, and 20 traps) in 20 plots (each 3 × 5 m2) using a completely randomized design. Thrips populations on pepper flowers were sampled from 1 to 29 July in 2009. All thrips sampled on the flowers were identified as F. intonsa. A significant effect of treatment and sampling date was found from repeated-measure analysis of variance. The highest density (20 traps per 15 m2) of traps significantly reduced the female and male F. intonsa population compared to the control by 61 and 49%, respectively. However, no difference in immature thrips numbers was found among the treatments. These results indicate that this flower model trap can be a useful tool for the management of flower thrips on field-grown peppers.

Skin contamination, airborne concentrations, and urinary metabolite excretion of propoxur during harvesting of flowers in greenhouses.

In eight greenhouses used for carnation culture, workers engaged in harvesting (n = 16), were monitored for dermal and respiratory exposure and urinary excretion of propoxur. Dermal exposure of hands and forearms was estimated from dislodgable foliar residue, using a transfer factor (a measure of transfer of pesticides from leaves to the skin) and the total number of working hours. Total estimated dermal and respiratory exposure during harvesting ranged from 0.2 to 46 mg and from 3 to 278 micrograms, respectively. To study the relationship between external and internal exposure to propoxur, respiratory and dermal exposure levels were compared with the total amount of 2-isopropoxyphenol (IPP), the major metabolite of propoxur, excreted in urine in 24 hr. The Pearson correlation coefficient between dermal exposure and the total amount of excreted IPP was 0.95. A correlation coefficient of 0.84 was found between respiratory exposure and the amount of IPP excreted. The latter association was probably caused by the covariation of respiratory and dermal exposure levels (r = 0.85). Assuming negligible oral absorption, calculations indicated that dermal exposure could account for > 80% of the amount of excreted IPP. On the basis of the amount of IPP excreted, there was no reason to suspect increased health risks for workers from exposure to propoxur during harvesting.

Ecology of the Endangered Species Solidago shortii. IV. Pollination Ecology

BUCHELE, DAVID E., JERRY M. BASKIN AND CAROL C. BASKIN (School of Biological Sciences, University of Kentucky, Lexington, KY 40506-0225). Ecology of the endangered species Solidago shortii. IV. Pollination ecology. Bull. Torrey Bot. Club 119: 137-141. 1992.-Like other species of goldenrod, cross pollination is required for seed set in Solidago shortii T. & G., and the percentage of flowers that produce seeds in this narrow endemic is similar to that in some of its geographically-widespread congeners. In field studies, seed set was 22-25.2% in openpollinated flowers, less than 1% in bagged flowers, 10.2% in hand-crossed flowers, and 0% in hand-selfed flowers. Seed set in hand-crossed and hand-selfed flowers in the greenhouse was 42.3% and 3.5%, respectively. The most frequent visitor to the flowers of S. shortii was the goldenrod soldier beetle, Chauliognathus pennsylvanicus, which is known to effect pollination in other Solidago species. Neither Apis nor Bombus was seen on inflorescences of S. shortii in the field. No major impact of herbivory was observed on the goldenrod. Thus, it appears that the narrow endemism of S. shortii cannot be explained on the basis of the breeding system and interactions with arthropods.

Anti-cholinesterase agents uptake during cultivation of greenhouse flowers

The cholinesterase (ChE) activities were measured in-season and out-season in a total of 204 greenhouse workers and 360 non-exposed controls. No seasonal ChE variation were observed in the controls, whereas an in-season depression was seen in the workers, indicating an uptake of anti-cholinesterase agents during cultivation of greenhouse flowers in the intervals between sprayings (p = 0.0001). The anti-ChE agents applied seem to persist in the greenhouses and cause continued subtoxic uptake for weeks since last application. Wearing of protective gloves did not prevent the uptake. Thus, chronic percutaneous and oral uptake occurs as a result of cultivation of greenhouse flowers.

Biological control of fusarium diseases by fluorescent Pseudomonas and non-pathogenic Fusarium

In soil-less culture of vegetables and flowers in greenhouses, fusarium diseases may induce severe damage. Under these growing conditions, biological control could be achieved by application of selected strains of fluorescent Pseudomonas or non-pathogenic Fusarium oxysporum. Seventy-four strains of fluorescent Pseudomonas were tested for their ability to reduce the incidence of fusarium wilt of flax when applied either alone or in association with one preselected non-pathogenic strain of Fusarium oxysporum (Fo47). Four classes were established, based on the effect of bacteria on disease severity, on their own or in association with Fo47. Most of the strains did not modify the percentage of wilted plants. However 10.8% of them, although having no effect on their own, significantly improved the control attributable to Fo47. One of these bacterial strains (C7) was selected for further experiments. Two trials conducted under commercial-type conditions demonstrated the effectiveness of the association of the bacterial strain C7 with the non-pathogenic Fusarium strain Fo47 to control fusarium crown and root rot of tomato, even when each antagonistic micro-organism was not efficient by itself. The yields were not significantly different in the protected plots in comparison with the healthy control.

Influence of Water Deficits on the Water Relations and Growth of Echinochloa turneriana, Echinochloa crus-galli, and Pennisetum americanum

Echinochloa turneriana (Domin) J. M. Black (Channel millet) is a wild grass native to the arid Channel Country of inland Australia, where it is used as forage and hay. In its native habitat flooding induces germination, and the plant can complete its life cycle with this single watering. The present study was conducted to gain a better understanding of the mechanisms which allow Channel millet to develop from germination to harvest with a single watering. Channel millet's drought resistance was compared with that of Pennisetum americanum (L.) Leeke (pearl millet), an important drought-resistant crop, and Echinochloa crus-galli (L.) Beauv. var. oryzicola (Vasinger) Ohwi (oryzicola), an obligate rice field weed. Plants of each species were grown under well-watered (control) and droughted conditions under long days in a greenhouse and under long and short days ifi a growth cabinet. Under long days, control and droughted Channel millet plants flowered before controls of pearl millet and oryzicola. Under long days and droughted conditions in the greenhouse flowering was delayed, and plant height, shoot dry weight, panicle number and tiller number were decreased in each species. Active osmotic adjustment under drought was detected in pearl millet by the pressure-volume and expressed sap methods, but was not observed in the other two species. The bulk modulus of elasticity decreased (cell wall elasticity increased) significantly under drought in Channel millet, but not in pearl millet or oryzicola. The apoplastic water volume was about 20% for all species and treatments. This study suggests that Channel millet's rapid development is important in helping the plant to complete its life cycle before the onset of a severe water deficit. Once severe water deficits develop, no osmotic adjustment occurs in Channel millet, and turgor is significantly decreased despite a decrease in the bulk modulus of elasticity.

Spider mite control practices in greenhouse flower crops

Spider mite control practices in greenhouse flower crops

Effect of Removal of Flower Buds, Open Flowers, Young Pods and Shoot Apex on Growth and Pod Set in Soybean

The complete removal of the reproductive structures once and shoot apices of soybeans (Glycine max L. Merrill) during early anthesis but before the rapid seed development stage significantly increased flowering and pod set in greenhouse and field grown plants. The treated plants had darker green leaves, shorter stems and petioles and retained their chlorophyll content longer than control plants. Pod maturation was also delayed. Although decapitation and the removal of reproductive structures increased the number of 3or more-seeded pods in all varieties tested, seed weight per plant was not consistently increased. The possible involvement of endogenous hormones in pod set and multi-locule pod production in soybeans is discussed.

Flowers with Abnormal Numbers of Involucral Bracts in Cotton1

A primitive race stock of cotton (Gossypium hlrsutum L.) Texas 703, had 26 to 59% flowers with more than the usual number of three involucral bracts in four seasons in the field at Phoenix, Ariz. The most common variant was a flower with a fourth, almost full‐sized bract, but other flowers had up to seven bract segments. Two cultivars, ‘Deltapine 16’ and ‘Stoneville 7A’, had lower frequencies of flowers with abnormal numbers of bracts. Plants of the race stock and cultivars had only three‐bract flowers in the winter greenhouse. We selected race stock ✕ cultivar F5 progenies that were almost true‐breeding for abnormal (98.9%) and normal (99.5%) numbers bracts. About one‐third of the F4 plants selected for all abnormals in the field had low frequencies of abnormals when cut back and moved into the greenhouse in the fall. The most common variant in the advanced‐generation selections, as in the race stock, was a flower with four bracts; one progeny had 95% four‐bract flowers. Others, however, had lower proportions of four‐bract flowers in relation to other abnormal numbers. Thus, it may be possible to select plants having flowers with more than four bracts. An inheritance study of selected F3 parents and four hybrid generations suggested that abnormal bract number is conditioned by three or four pairs of genes that show additive, intra‐allelic, and interallelic effects.

ナフトキノン誘導体, 2-benzimidoy1-3-hydroxy-1,4-naphthoquinone がトマトの生育に及ぼす影響 (第1報)

1) Parthenocarpy of dwarf tomato (cv. Miniature) induced by synthetic naphthoquinone derivatives was investigated. 3-Phenyl-4, 9-dihydronaphth [2, 3-d] isoxazole-4, 9-dione, 2-benzimidoyl-3-hydroxy-1, 4-naphthoquinone, 2-(3--methoxyben-zimidoyl)-3-hydroxy-1, 4-naphthoquinone, 2-(3-pyridylcarbimidoyl)-4 hydroxy-1, 4-naphthoquinone, 2-(4-chlorobenzimidoyl)-3-hydroxy-6, 7-dimethyl-1, 4-naphthoquinone, 6-(or 7-) benzimidoyl-7 (or 6-)-hydroxy-5, 8-dihydroquinoline-5, 8-dione, 2 (N-methylbenzimidoyl)-3-hydroxy-1, 4-naphthoquinone, 2-benzoyl-3-hydroxy-1, 4-naphthoquinoe, 3, 5'-diphenyl-4-oxo-4, 9-dihydronaphth [2, 3-d] isoxazole-9-spiro-', 3', 4'-dioxazole) and 3, 5'-diphenyl-4, 5-dihydro-naphth [2, 1-d] isoxazole-5-spiro-2', 1', 3', 4'-dioxazol-4-one induced clearly parthenocarpic fruits. These compounds are of a new type of plant growth regulators and their chemical structures are different from those already known.2) One of these compounds, 2-benzimidoyl-3-hydroxy-1, 4-naphthoquinone (bendroquinone) was applied to emusculated tomato (cv. Fukuju Ni-Go) flowers. The parthenocarpic fruits showed the same development of fruit as by application of synthetic auxins, HCPA and 4CPA.3) The ovule development of the parthenocarpic fruits was histologically observed. The development of the endothelial cells induced by bendroquinone was not so active as that by HCPA for a period of two weeks after anthesis, but one week later, there was no difference in the development of the pseudoembryo between applications of the two chemicals.4) Bendroquinone isn′t easily soluble in water. It was formulated as 9% wettable powder and applied to tomato (cv. Beiju) flowers in a plastic green house as the setting agent. The fruit set percent and the yield of the first cluster were not so high as compared with the application of HCPA and 4CPA, but in case of the second, the third and the fourth clusters, they were higher. The fruit set percent and the total yield per plant by the application of 200ppm and 300ppm bendroquinone, 200ppm HCPA and 30ppm 4CPA were respectively 73.8% 15.92kg, 78.8% 15.66kg, 73.9% 16.03kg and 60.2% 13.34kg. The puffiness extent of the fruits was slight and there was no phytotoxicity on the plant.5) For induction of parthenocarpy by bendroquinone, the application at earlier stages of flower development was effective as compared with HCPA and 4CPA. The induction of parthenocarpy related closely to the volume and the time retained on the calyx. Therefore, addition of the spray adjuvant would be good for the induction.

AREAL SPECIALIZATION OF GREENHOUSE HORTICULTURE

Under the rapid economic development in which class stratification is being taken place among Japanese farmers, the viable farmers are enlarging their farm size and specializing their products. In other words, areal scale of production is widening and specialization in product is extending. This paper is a consideration on areal specialization of greenhouse horticulture with the following results. 1. Considering the national acreage of greenhouses by Prefecture, three Prefectures of Aichi, Shizuoka and Okayama occupy 61.7% of the total, showing a remarkable concentration and the distribution of greenhouse horticulture is also concentrated in those regions with a high population density along the Tokaido and San'yo railways, In greenhouse horticulture, melons grapes, chrysanthemums by electric lighting and carnations are the main products, each of which is remarkably specialized areally. In addition to this, the degree of regional accumula-tion and specialization in product is being intensified, and the large scale growing in the exist-ing greenhouse horticulture areas is contributing greatly to the increased products by green-house horticulture. 2. Taking examples of flower greenhouse growing areas in Aichi Prefecture, the Atsumi area in which chrysanthemums are grown in a large scale by electric lighting, is being pushed f oreward to organize the area, as a whole, for its production through co-operative marketing and consolidation of greenhouse sites. The Yokosuka area, Tokai-shi in which decorative plants are grown, is now being enforced to change the production method from the small-scale pro-duction of the variores species to be sold at higher prices for their scarcity to the mass produc-tion of a few species which have a greater popularity. But organizing the area in a large scale production method has been retarded in the Atsumi area owing to the scattered location of individual growing farmers. 3. Recent areal specialization in greenhouse horticulture has advanced by enlarging the size of existing horticultural farms but not by increasing the number of farms. The farmers are adapting the mass production method of specialized crops as farm size becomes larger. In the background, it can be noticed that the prices of flowers have been going upward accord-ing to the increased demand through both the popularization of flower consumption and the enlargement of marketing organization on one side, and the realization of mass production is largely due to the standardization of growing techniques and saving labour as well as sufficient labour equipped with a high still on the other. It is emphasized to say that the adaptation of the farmers to the national policies is the most important in establishing a highly specialized area in greenhouse horticulture.

The Breeding Systems of Lupinus, Group Micranthi

Lupinus section Micranthi is a group that contains many small flowered annual lupines and ranges from British Columbia to northern Mexico. They have the characteristic flower of the Pea family, and like many, if not most, of its members are self pollinated to a large degree, because of the floral structure, the keel containing both the stamens and style in close proximity. While studying the taxonomy of this group and growing some of its members for purposes of comparison, it was observed that in the greenhouse flowers of l. bicolor regularly set seed, but that those of L. nanur failed to do so. Were it not for the self pollinating mechanism this might have been attributed to the absence of insects. Preliminary investigation indicated a difference in the way that this mechanism operates and hence a difference in the variation pattern of the two species. The purpose of this investigation is to ascertain and clarify these differences. First the structure of the flower is carefully analyzed and thereafter follows a discussion of the insect relationship and how bees operate the pollination mechanism in L. nanus. Experiments designed to study the rate of floral development, the time of stigma receptivity, and the period of pollen viability are then presented and their bearing on selfing and outcrossing is discussed. I am under obligation to Professor Carl Epling for advice and guidance.