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In cut rose crops, harvest of a mature shoot triggers axillary buds on the remainder of the shoot to grow. This budbreak is an important event in a cut rose crop because it is one of the factors determining the number of harvestable shoots, next to
Abstract
In vitro cultures were used to study the development of axillary bud and stolon tip explants of cultivated strawberry (Fragaria × ananassa Duch.). Explants cultured on Murashige-Skoog basal media containing kinetin at 1, 5, or 10 mg/liter developed into leafy shoots. Low concentration of kinetin (1 mg/liter) promoted the development of both types of explants into single shoots while higher concentration (10 mg/liter) promoted production of multiple leafy shoots developing from axillary buds of the earlier formed leafy shoots. NAA at 1 mg/liter promoted callus growth from both types of explants. Axillary bud explants developed into stolons when cultured on media containing gibberellic acid (GA3) at 5, 10 or 20 mg/liter. Stolon apices developed into leafy shoots while the second axillary stolon buds of the tips were inhibited when the explants were cultured on GA3-containing media. Combinations of GA3 and kinetin induced the development of axillary bud explants into structures intermediate in form between those of stolons and leafy shoots. Stolon apices and stolon axillary buds at the stolon tips developed into leafy shoots and continuing stolons, respectively, when the explants were cultured on a kinetin-containing medium for one week, and then transferred onto a GA3-containing medium. Thus, the developmental pathway of axillary strawberry buds was shown to be responsive to a balance between GA and cytokinins following removal from apical dominance.
To produce the homozygous strain of a haploid plant derived from small seed-derived seedlings of `Banpeiyu' pummelo (Citrus grandis Osbeck), we carried out colchicine treatment to axillary shoot buds of the haploid. Many shoots with cytochimeras (X+2X and 2X+4X) arose from the colchicine-treated axillary buds. When cytochimeric buds of 2X+4X were top-grafted onto trifoliate orange [Poncirus trifoliata (L.) Raf.], a complete diploid shoot with 18 chromosomes was obtained from the cytochimera. This diploid strain showed vigorous growth compared with the original haploid. The leaf weight per unit area and the stomata size in this diploid were significantly larger than those of the original haploid plant, and were almost equal to those of `Banpeiyu' pummelo. The diploid strain was confirmed to be a doubled haploid of a haploid from `Banpeiyu' pummelo, based on random amplified polymorphic DNA (RAPD) analysis and chromosome composition analysis by chromomycin A3 (CMA) staining.
The effect of temperature on axillary bud and lateral shoot development of poinsettia (Euphorbia pulcherrima Willd.) `Eckespoint Lilo' and `Eckespoint Red Sails' was examined. Rooted `Eckespoint Lilo' cuttings were transplanted and placed into growth chambers maintained at 21, 24, 27, or 30 °C for 2 weeks before apex removal. The percentage of nodes developing lateral shoots after apex removal was 68%, 69%, 73%, or 76% at 21, 24, 27, or 30 °C, respectively. Cuttings were removed from the lateral shoots, rooted, and placed into a 21 °C greenhouse, and the apices were removed. The percentage of nodes developing into lateral shoots on cuttings taken from plants held at 21, 24, 27, and 30 °C were 74%, 65%, 66%, and 21%, respectively. Of the cuttings in the 30 °C treatment, 83% of the nodes not producing a lateral shoot had poorly developed axillary buds or no visible axillary bud development. Visual rating of axillary bud viability decreased from 100% to 0% when `Eckespoint Red Sails' plants were transferred from a 21 °C greenhouse to a greenhouse maintained at 27 °C night temperature and 30 °C for 3 hours followed by 33 °C for 10 hours and 30 °C for 3 hours during the 16-hour day. Transfer from the high-temperature greenhouse to a 21 °C greenhouse increased axillary bud viability from 0% to 95%. Axillary buds of leaves not yet unfolded were sensitive to high temperatures, whereas those of unfolded leaves (i.e., fully developed correlatively inhibited buds) were not. Sixteen consecutive days in the high-temperature treatment were required for axillary bud development of `Eckespoint Red Sails' to be inhibited.
This study was undertaken to determine if endogenous IAA content and axillary bud development correlate with phenylalanine ammonia-lyase (PAL) induction and russet spotting (RS) susceptibility among RS susceptible and resistant cultivars of Iceberg lettuce (Lactuca sativa L.). Final levels of ethylene-induced PAL activity and RS development were highly correlated among cultivars, field conditions, and harvest dates. Harvested Iceberg lettuce midribs contained relatively low amounts of free IAA (maximum of 5.2 ng·g-1 fresh weight). There was poor correlation between free IAA content in lettuce leaf midribs and final RS development among all cultivars, growing conditions, and harvest dates. Axillary bud development, as measured by the number of visible buds per head, bud weight, or bud length, were not significantly correlated with final RS development or midrib IAA content. Cultivars with higher initial free IAA content lost much of their IAA after 8 days storage at 5C in air ± ethylene.
Abstract
Sprouting of axillary shoots was studied in nursery apple trees (Malus domestica Borkh) following defoliation and Promalin application. Both Promalin and defoliation stimulated lateral bud outgrowth. Promalin was more effective when applied to buds without the inhibition imposed by the subtending leaf. In the absence of the subtending leaves there was a decreased tendency for buds to sprout at lower node positions. Buds most responsive to Promalin were between those subtended by small, partially expanded leaves and those subtended by fully grown leaves.
Abstract
2,3,5-triiodobenzoic acid (TIBA), (2-chloroethyl) phosphonic acid (ethephon), 6-(benzylamino) - 9 - (2-tetrahydropyran-yl) - 9 H-purine (PBA), and N6 benzyl adenine (N6BA) were applied to greenhouse rose cvs. Red American Beauty, Forever Yours, Mary DeVor and Jack Frost as sprays, lanolin paste, and in solutions in floral foam. Axillary shoot development was significantly increased when PBA and N6BA were applied as sprays, in paste or in solutions in floral foam. The most significant response was obtained when the chemical solutions were absorbed from floral foam cubes attached to a cutback rose cane. Most of the axillary buds broke dormancy when the growth regulating chemicals were applied by this method, however, many of the developing buds stopped growth before becoming shoots. Chemicals PBA and N6BA significantly increased the development of flowering and blind shoots for all rose clones. Plant growth regulating chemicals, methods of application, and concentrations favorable for the development of axillary shoots had no comparable effect on basal shoots developing from the rose bud union.
associated with the origins of crown buds and bud clusters, and plant ontogeny, is required to develop techniques for manipulation of bud initiation and shoot emergence for horticulture. In terms of types of buds, axillary buds are typically of exogenous
axillary buds on the shoot remainder, generating new shoots, which constitute the next harvest. Before a shoot is harvested, the axillary buds on the lower part of the shoot do not grow out because signals from the shoot above it inhibit their growth. Such
growth of axillary buds ( Domagalska and Leyser, 2011 ). CmMAX1 decreased significantly after 2 h of GR24 treatment, which indicated there was a feedback regulation in the synthesis pathway of strigolactone. The application of 6-BA caused a decrease in