Showing papers by "Tony H. H. Chen published in 1991"

Photoperiod Control of Poplar Bark Storage Protein Accumulation

Abstract: Bark storage proteins (BSPs) accumulate in the inner bark parenchyma of many woody plants during autumn and winter. We investigated the effect of a short-day (SD) photoperiod on the accumulation of the 32-kilodalton bark storage protein of poplar (Populus deltoides Bart. ex Marsh.) under controlled environmental and natural growing conditions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and protein gel blot analysis revealed that 10 days of SD exposure (8 hours of light) resulted in a 20% increase in the relative abundance of the 32-kilodalton bark storage protein of poplar. After 17 days of SD exposure, the 32-kilodalton bark storage protein accounted for nearly one-half of the soluble bark proteins. In natural field conditions, accumulation of the 32-kilodalton bark storage protein was observed to start by August 18 (daylength 14.1 hours). Immunoprecipitation of in vitro translation products with anti-BSP serum revealed that the SD protein accumulation was correlated with changes in the pool of translatable mRNA. A survey of poplar clones from different geographic origins revealed the presence of the 32-kilodalton BSP in the dormant bark of all the clones tested. These results demonstrate that a SD photoperiod induces, whether directly or indirectly, rapid changes in woody plant gene expression, leading to the accumulation of BSP.

Changes in the Translatable RNA Population during Abscisic Acid Induced Freezing Tolerance in Bromegrass Suspension Culture

Abstract: Abscisic acid has been shown to increase freezing tolerance of bromegrass cell suspension cultures. Our objective was to study the qualitative changes in the translatable RNA population during ABA induced frost tolerance. In vitro translation products of poly(A) + RNA isolated from bromegrass cells with or without 75 μM ABA treatment for various periods of time were separated by 2D-PAGE and visualized by fluorography. SDS soluble proteins from the same treatments were also separated by 2D-PAGE

Adventitious Shoot Production from a Vireya Hybrid of Rhododendron

Abstract: An efficient adventitious shoot production protocol has been developed for Rhododendron laetum × aurigeranum. Shoot tips taken from greenhouse-grown plants were cultured on Anderson's medium supplemented with 74 µM 2iP. Axillary shoots were excised and cultured on medium containing 23 µM IAA and 74 µM 2iP. After 6 months, brown callus developed at the cut surfaces of the shoot-tip explants. This callus produced many adventitious shoots (up to 70 per explant). Clusters of adventitious shoots were divided, subculture, and continued to proliferate shoots. An estimated 1600-fold increase in the number of shoots could be readily achieved in 6 months. In vitro rooting of adventitious shoots was accomplished in 4 weeks. Seventy-three percent of shoots rooted on 1/4 strength Anderson's medium supplemented with 28 µ M IAA. Plantlet survival was 100%3 weeks after transfer to soil. Chemical names used: 1-H- indole-3-acetic acid (MA); N-(3 -methy1-2-butenyl) -1H-purine-6 amine (2iP). The genus Rhododendron, section Vireya, comprises ≈ 300 species endemic to South- east Asia (Sleumer, 1966). Almost half of the 300 Vireya species, including the species R. laetum J.J. Smith and R. aurigeranum Sleumer, are native to New Guinea, which lies between lat. 2° and 12°S. According to the Royal Horticultural Society (Leslie, 1980), Vireya rhododendrons are classified as "nor- mally requiring greenhouse protection dur- ing the winter months". Those species native to low altitudes in New Guinea are irrepar- ably damaged if exposed, even for a short time, to temperatures below 0C (Withers, 1984). Since Vireya rhododendrons do not require a resting period, they may flower at any time of the year. Therefore, they may have potential as greenhouse-gr own orna- mental plants. Moreover, they represent a source of breeding material for the improve- ment of hardy rhododendron flower quality. Vireya flowers range from < 1 cm to 10 cm in length and have a variety of colors, from white to yellow, from orange to deep red; the flower has diverse shape, from tubular

Plant regeneration from somatic tissue of Rhododendron laetum x aurigeranum

Abstract: The influence of the source of plant material (greenhouse-grown plants or in vitro shoot cultures), the type of tissue explant (shoot-tip, single-node stem segment, whole leaf, leaf strip or half-leaf section) and growth regulator concentration on shoot regeneration from somatic tissue of Rhododendron laetum × aurigeranum was evaluated. No regeneration response was obtained on explants from greenhouse-grown plants. Adventitious shoots were obtained from callus produced at the basal end of shoot-tip and single-node stem segment explants derived from in vitro-grown shoots cultured on Anderson's medium supplemented with 22.8 μM IAA and 73.8 μM 2iP. The greatest percentage of adventitious shoot regeneration (77%) was induced on leaf sections cultured in the presence of 22.8 μM IAA and 147.6 μM 2iP. Plant regeneration was accomplished with minimal callus formation. This technique represents a further step toward gene manipulation of Rhododendron.

Desiccation Tolerance in Bare-rooted Apple Trees Prior to Transplanting

Abstract: Ten types of apple (Malus domestica L.) trees (six different scions on M.7 rootstock and four ‘Red Delicious’ scions on M.7, MM. 111, MM.106 and seedling rootstocks) were subjected to air drying for periods of 0 to 48 hr with or without 3 months of cold storage at 0°C (32°F). The kinetics of water loss during drying treatment and the transplanting survival and regrowth vigor were recorded. Both the scions and rootstocks influenced the tolerance of apple trees to desiccation stress. Among the plant materials tested, ‘Red Delicious’ on MM. 111 rootstock had the highest level of tolerance to desiccation. Three months of cold storage at 0°C (32°F) resulted in the considerable loss of tissue water, but the grafted trees survived if no further desiccation occurred prior to planting. Only ‘Red Delicious’/MM. 111 tolerated desiccation from the combination of three months of cold storage followed by a 48 hr exposure to air drying, while other scion/rootstock compound systems seldom survived. The analyses ...