Programmed flower induction of Calathea crocata Morr. et Joris is possible under the controlled environmental conditions of a multilayer growing room. A photoperiod of 10 hours for 9 weeks, growth at 18C, and a photosynthetic photon flux density (PPFD) of 71 μmol·s-l·m-2 induced flowering in more than 95% of the plants and in 50% to 80% of the shoots. In the meantime, none of the plants under natural conditions was induced. Significantly more flowers were induced when PPFD during the short-day treatment was 71 rather than 56 μmol·s-1·m-2. Flowers became visible 14 to 16 weeks after the start of the inductive treatment. Moreover, raising the CO2 concentration to 900 ppm for 5 months increased the leaf area and dry weight by 40%, and resulted in darker leaf color, longer flower stalks, and significantly accelerated flowering (10 days).
Abstract
Successful in vitro propagation of white rubber rabbitbrush [Chrysothamnus nauseosus (Pallas) Britt, ssp. albicaulis] was achieved using both stem segments and axillary shoot explants. Medium stem segments (2–3 mm diameter) were more successfully cultured than either small (0.8–1 mm diameter) or large (4–5 mm diameter) explants. Axillary shoot explants (10–15 mm long) began to form roots within 1 week after placement in media containing 5–10 μM (1–2 mg/liter) indolebutyric acid (IBA) or 5.3–10.6 μM (1–2 mg/liter) naphthalene-acetic acid (NAA). Root growth was accelerated in the presence of IBA. In the presence of 8.9 μM (2 mg/liter) benzyladenine (BA) and 0.53μM (0.1 mg/liter) NAA, both medium stem segments and axillary shoots rapidly produced numerous side shoots that were rooted easily on media containing IBA. In vitro culture appears to be a feasible means for the mass multiplication of this potentially important rubber-producing shrub.
The effects of various media, varying concentrations of sucrose, plant growth regulators, and inorganic salts such as KNO3, KH2PO4 and NH4NO3 on callus Formation and anthocyanin synthesis in carrot cell culture were studied. The greatest calli and anthocyanin pigments were obtained by SH and Nitsch & Nitsch medium, respectively. Nitsch & Nitsch medium supplemented with 55g/l sucrose, 0.2g/l NAA and 0.1g/l BA was effective for both callus and anthocyanin production. Anthocyanin synthesis was accelerated by increasing concentration of KNO3, while suppressed by NH4NO3. However, KH2PO4 promoted anthocyanin synthesis at half strength. These results suggest that physiological factors on anthocyanin production by plant cell culture could provide the possibility of application to other crops for secondary metabolites production and mass production system establishment of anthocyanin as an important natural pigment in cosmetic and food industry.
Growth and physiological responses of Intsia bijuga trees to flooding were determined in a series of five container experiments to assess the relative tolerance of this species to flooding. The first measurable response to flooding was reduced leaf gas exchange, which began within 5 to 6 days of the onset of flooding. Development of hypertrophied lenticels at the water line and paraheliotropic leaflet movement were evident by 17 days of flooding. Emergence of adventitious roots on the stem above the water line began after about 30 days of flooding. Leaflet abscission was greatly accelerated by flooding. After more than 3 months of flooding, regrowth of roots, stems, and leaves began within two weeks of draining the medium. The data and observations support a relative ranking of moderate flood tolerance for Intsia bijuga.
Abstract
A technique using 2-branched rooted cuttings of azalea ‘Hexe’ was devised to provide uniform plant material for studying the effect of photoperiod and growth regulators on early stages of flower bud initiation and development. Flower initiation was most rapid under 8-hr daylengths, as a definite change of shape of apex was observed the 4th to 5th weeks. No change was observed on plants subjected to interrupted nights with 50 ft-c incandescent light supplied between 10 pm and 2 am.
Short days plus a drench of 0.4 g Cycocel, (2-chloro-ethyl) trimethylammonium chloride, accelerated initiation over short days alone. Gibberellic acid applied to Cycocel-treated plants at 3 and 4 weeks of short days delayed flower initiation. Gibberellic acid applied to short day plants during the 4th to 6th weeks was effective in preventing flower initiation in this cultivar.
artificially induced, then a large block of time can be opened during the colder months for genetic testing, early phenotyping, and additional plant growth. Materials and Methods Plant material. Open-pollinated seeds (≈1800 seeds per cultivar/selection) were
Abstract
Ten to 100 ppm ethylene in air inhibited the development of superficial senescent spots on ripe bananas (Musa cavendishii Lambert cv. Valery). The ethylene did not affect the respiration rate but accelerated softening of the partially ripe or ripe bananas at 21°C. Six days of continuous exposure to 10 ppm ethylene did not affect the eating quality of bananas but 9 days of exposure slightly lowered the quality. Ethylene did not inhibit anthracnose (Gloeosporium masarum Cke. & Mass.) growth on banana fruit or on petri dish culture. Dipping ripe bananas in 100 to 1000 ppm (2 chloroethyl)phosphonic acid (ethephon) did not inhibit the senescent spot development. Brief dipping in silver nitrate solution (50 mg/liter) counteracted the ethylene effect.
Abstract
Seedlings of tomato (Lycopersicon esculentum Mill.) (15 to 22 days old) exposed to unbuffered solutions containing N solely in the NH4 form showed poorly developed, thickened, less branched, discolored root systems, marginal necrosis of some leaves, wilting, particularly dark green foliage, and restricted growth. Calcium carbonate at 0.5 g/liter alleviated NH4 toxicity and restricted the accumulation of free NH4 in roots, bleeding sap, and shoots even though NH4 uptake rates were accelerated by CaCO3. Thus, the beneficial effect was related to enhanced NH4 assimilation. Roots contained an active NADH-specific L-glutamate dehydrogenase, but in vitro activity was correlated with internal NH4 content and, therefore, did not reflect actual NH4 assimilation rates during experimental periods.
A seedling disorder of broccoli (Brassica oleraceae L. var. italica) characterized by chlorotic cotyledons and delayed seedling growth is described. This disorder, termed “yellow cotyledon”, has been observed in field plantings under high temperatures with some broccoli seed lots. Yellow-cotyledon disorder can be observed in laboratory germination tests if they are conducted under illumination, where unaffected seedlings will develop green cotyledons. Little relationship was found between overall seed vigor and the expression of yellow cotyledon by use of early germination counts and accelerated aging tests, although the most severely affected seed lots had been stored for several years. Field trials in 2 years showed that although seedlings with yellow-cotyledon disorder developed into normal plants, maturity was delayed and total yields were reduced.
Synthesis of non-ethylene volatiles (NEV) undergoes significant alterations during the transition from vegetative growth to senescence in apple fruit. This change results in a substantial increase in the production of esters characteristic of ripe apples. The relationship between changes in NEV synthesis and other indicators of physiological and horticultural maturity were investigated using `Bisbee Delicious' apples. Analysis of NEV was conducted using headspace sampling and GC-MS. Aldehydes and alcohols were the largest NEV components from pre-climacteric fruit although several esters were detected. The concentration of all NEV components declined to a minimum prior to the onset of the climacteric rise in ethylene synthesis. Initial detection of 2-methyl butylacetate, the major ester in ripening `Bisbee Delicious' fruit, occurred several weeks prior to the onset of the climacteric. The increase in ester synthesis accelerated during the post-climacteric period and the amount of total aldehydes also increased.