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  • Author or Editor: E. R. Emino x
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Abstract

In vitro propagation of Mammillaria elongata DC plants was successful using tubercle explants grown on a medium based on Murashige and Skoog’s high salts supplemented with various auxins and cytokinins. Optimum callus proliferation occured in response to 2,4-dichlor-ophenoxyacetic acid (2,4-D) (2-10 mg/liter) with either kinetin or 6-(dimethylallylamino)-purine (2iP) (1-2 mg/liter). Root initiation was optimized with either napthaleneacetic acid (NAA) or indolebutyric acid (IBA) (60 mg/liter). Shoot initiation was optimized by addition of 2iP (10 mg/liter) and indoleacetic acid (IAA) (1 mg/liter). The auxin:cytokinin balance required for shoot initiation appears to be unique for each species of Mammillaria studied. Shoots developed in vitro of M. elongata were successfully transferred to greenhouse conditions, where they rooted and continued to grow.

Open Access

Abstract

Bulk density, moisture holding capacity, pH, initial nutrient level, aeration or soluble salt characteristics were not consistently related to growth response in 6 commercial growing media. Growth of Tradescantia albiflora Kunth ‘Albovittata’, Hemigraphis alternata (Burm,f.) T. Anderson, Wedelia trilobata(L.) A. S. Hitchc, Peperomia obtusifolia (L.) Dietr., Lycopersicon esculentum Mill. ‘Better Boy’, and Hypoestes phyllostachya Bak. were highly variable among media.

Open Access
Authors: and

Abstract

Chrysanthemum plants (Chrysanthemum morifolium Ramat. cv. Bright Golden Anne) were grown for 84 days in plastic pots containing 6 different media treated with inorganic fertilizers or liquid digested sewage sludge at 50, 100, and 200 ml/week. Plants grown in 1 soil: 1 sand: 1 peat, 1 soil: 1 sand, and 1 soil: 1 peat were similar to each other in size, and larger than plants grown in 1 sand:1 peat, all sand, or all peat. Peat-grown plants were smallest. Plant size and flower diameter decreased with increasing rates of sludge application. Plants fertilized with inorganic sources of fertilizer looked the same as those grown with 50 ml/week sludge (6 mm), except the sludge-treated plants were shorter and had a smaller dry weight. Plants treated with 50 ml/week sludge had flowers with a diameter and dry weight equal to those of flowers grown with liquid or pelletized inorganic fertilizer.

Open Access
Authors: and

Abstract

Axillary meristems of Mammillaria elongata DC were studied with a scanning electron microscope using fresh tissue to determine their degree of development and suitability as explants in tissue culture investigations. Meristems were excised at regular intervals along the stem. The axillary meristem reached maximum size about 10 cm and maximum development about 15 cm below the stem tip. Axillary meristems closer to the base of the stem were less developed. In fully developed meristems, leaf primordia were initiated in a spiral acropetal sequence at the margins of the apical dome, resulting in a phyllotaxis of 8 + 13 contact parastichies of tubercles on the developed stem. Enlarged leaf primordia were 1- or 3-lobed and about 75 μm in length. No flower initiation or lateral branch development was observed; however, a corky region, the result of aborted or senesced flowers, was observed in several axils. Variability in development or absence of axillary meristems in several axils make M. elongata axillary meristems unsuitable for critical studies on factors influencing organogenesis in tissue culture.

Open Access
Authors: and

Abstract

Fungal and fire treatments were applied to seeds of Albizia julibrissin to simulate natural mechanisms of seed coat scarification. Seeds in unsterilized soil which contained natural microorganisms resulted in increased germination compared to seeds in sterilized media. Germination in cultures of Rhizoctonia, Fusarium, and Pythium indicated Rhizoctonia was most effective as a seed scarifier. Fire treatment at 1, 3, 5, and 10 seconds indicate that 1 second enhanced seed germination. Scanning electron micrographs of treated seed indicated that fungal hyphae alters the surface of the macrosclereid cells which may allow for imbibition of water. Seeds sub-jected to fire had large cracks in the macrosclereid layer.

Open Access
Authors: and

Abstract

Spine primordia of Mammillaria elongata are initiated in acropetal sequence, beginning on the abaxial side of the spiniferous meristem that occupies the summit of a young tubercle and continuing along either side until a single whorl is completed. If a central spine occurs, it is the last to be initiated and the first to begin elongation. Elongation of the whorled spines follows a basipetal sequence, the inverse of initiation. All elongated spines are at first erect, but the lateral ones become radially oriented as they appraoch maturity. Central spines remain erect and tilted slightly toward the shoot apex. The distal ends of many epidermal cells on developing spines bear conic projections that are most prominent along the median portions.

Open Access

Abstract

Intact shoot apex development of the carnation was studied with a scanning electron microscope using fresh tissue. Reproductive meristems were more resistant to desiccation from the hard vacuum and electron beam than vegetative meristems. Vegetative meristems, however, can be studied if the work is done quickly.

Structural changes which occurred in the developing carnation shoot showed that leaf primordia are initiated in a circular whorl. Floral initiation was easily determined by the appearance of a flattened apex and a pentagonal whorl of sepal primordia. Subsequent centripetal initiation of flower parts was easily recognized and identified.

Open Access

Abstract

Nitrogen zinc nitrate solution was applied to 18 species of container-grown woody ornamentals to determine if Zn levels could be increased and related to increased growth and plant quality. In 13 species there was an increase in Zn concentration as compared to untreated plants. Quality was improved in 3 species without a related increase in Zn content. Fe and Mn concentrations were unaffected in most species and no phytotoxicity was observed.

Open Access

Abstract

Adaxial and abaxial leaflet surfaces of juvenile and adult pecan [Carya illinoensis (Wang.) K. Koch] leaves were characterized in relation to leaf age. Three types of trichomes were found. Nonglandular hairs (acicular and fasciculate) were the most common trichome type on juvenile-phase leaves and reached their greatest density on the abaxial surface of immature leaves. Peltate scales were present in two forms: vesicular scales and concave scales. The two were distinguished on the basis of size and shape. Both types were more common on the abaxial than the adaxial surface. The vesicular scales were more common on immature than mature leaves, whereas the occurrence of concave scales were unaffected by leaf age. Capitate glands were observed on the veins of immature leaves in both juvenile and adult phase. Laminai stomata of two sizes and unusual veinal stomata were observed, the latter being confined to the abaxial surface of immature leaves.

Open Access

Abstract

Four bromeliad species in the genus Neoregelia were studied by scanning electron microscopy (SEM) for morphological characteristics and density of trichomes that may influence absorptive capacities. Neoregelia trichomes were classically peltate, generally elliptic, exhibiting a web-like cap characteristic of the Bromelioideae. Minor variations were evident between species in morphology, density, and distribution. Copper from copper sulfate applied to leaf surfaces was absorbed and translocated as determined by atomic absorption spectrometry, but uptake was not related to trichome density as determined by SEM nondispersice technique.

Open Access