tea plant using 6-BA after heavy pruning in summer. The adult tea plants of Longjing 43 were used in the present study. The promoting effect of exogenous 6-BA on tea plant dwarfing, lateral bud sprouting in advance, lateral branch growth, and spring
Liping Zhang, Chen Shen, Jipeng Wei, and Wenyan Han
T. K. Bose, B. K. Hore, and D. Mukherjee
Cycocel (2-chloroethyl trimethyl ammonium chloride) inhibited shoot growth and increased number of flowers in azalea (1) and Gardenia jasminoides (2), while height of poinsettia (3) and chrysanthemum (4) was also effectively controlled by the application of the chemical. Some varieties of Bougainvillea grew dwarf and bushy with markedly improved flowering following application of Cycocel (5). In view of the great possibility offered by the growth retardants, an extensive investigation to study the efficacy of these chemicals on large number of species and varieties of tropical ornamental plants belonging to different families was begun. The results of the effect of Cycocel on growth and flowering of some popular ornamental plants belonging to family Malvaceae are reported.
C. S. Kauffman and R. L. Lower
An extreme dwarf plant type in cucumber (Cucumis sativus L.) is controlled by the homozygous recessive state of a simply inherited gene, designated cp for compact. The dominant allele yields the standard vine type plant. The gene is inherited independently from the gene for determinate dwarf habit, de. The mode of action of the recessive allele, cp, is to reduce the length of the individual internodes, but it apparently has little effect on the total number of internodes. Seed size of fruits from compact plants is also reduced.
Qingrong Sun, Yinping Shi, Qiangsheng Wang, and Hongyan Sun
Laiyang dwarf cherry (Prunus pseudocerasus Lindl. Var. Laiyang dwary cherry) is an important dwarf type of Chinese cherry. It is both directly used for production and used as rootstock of sweet cherry (P. avium L.). Material used in this study was Laiyang dwarf cherry seed, which is open-pollinated. The fruit surface is sterilized with 70% ethanol on sterile working table, the seed is removed from fruit, and embryo is taken out of cracking seed shell. Explants include whole embryo, embryo without cotyledons, and cotyledons. Basal media are MS and 1/4MS major elements, sugar 30 g·L–1, agar 5.5 g·L–1, adjusted pH 5.8. Hormone used included 6-BA,IBA and 2,4-D for a total eight treatments. Culture temperature was 25° ±2°C, and photoperiod was 14 h. Results show 1) the plant regeneration rate from cotyledons is highest, second is from embryo without cotyledons, lowest is from whole embryo; 2) when BA is in the range of 0.7 to 5 ppm, plant regeneration is higher at a high concentration than that at low concentration; 3) at the same concentration, plant regeneration rate on the medium supplemented with 2,4-D is higher than that on the medium supplemented with IBA; 4) plant regeneration rate is higher on the medium containing cytokinin and auxin is higher than that on the medium only containing cytokinin; and 5) plant regeneration rate of continuous light culture cotyledons is higher than that of first dark culture 2 weeks cotyledons. Effects of light and dark/hormone and explant type on plant regeneration rate is discussed.
M. A. L. Smith, S. L. Knight, and M. J. Bass
A whole plant microculture (WPMC) screening system facilitated rapid, quantitative appraisal of salt stress effects on `Micro-Tom' miniature dwarf tomato. Axillary bud explants were micropropagated on a hormone-free control medium (conductivity = 3.3 dS m-1), gradually introduced to treatments with increasing NaCl or Na2SO4 concentrations via biweekly subculture to fresh media (7,6, 12.8, or 18 dS m-1), and monitored over a subsequent 5 week culture period. Non-intrusive video image analysis techniques were adapted to quantify morphometric (shoot growth rate, area, and length; root length and area) and photometric (ruler and tissue quality) plant responses. Shoot growth was only slightly inhibited at 7.6 and 12.8 dS m-1, but was severely stunted and distorted on high salt (18 dS m-1) media. Root growth inhibition (significantly shorter and thinner primary rants) was first evident at 12.8 dS m-1 after 3 weeks of treatment. At 18 dS m-1, conspicuous retardation of root growth relative to controls could be gauged after only one week. Shoot tip chlorosis was observed in the lowest salt-supplemented treatment after three to four weeks of culture, but overall shoot yellowing at the two highest conductivities was marked after only a few days. Chlorosis symptoms were not uniform within treatments. Cell osmotic concentration showed a linear increase with increasing medium salinity. The WPMC system expedited time course observations of stress symptom development, paralleled stress response trends observed in solution culture tests, and provided an excellent vehicle to investigate plant adaptation to saline conditions.
Zhanao Deng, Brent K. Harbaugh, and Natalia A. Peres
encouraged to prolong their life. Availability The caladium cultivars UF-331 and UF-340 will be sold and marketed under the trade name Angel Wing Dwarf Tricolor and Angel Wing Dwarf White. A plant patent application will be submitted to the U
Jay Frick, S. Suzanne Nielsen, and Cary A. Mitchell
. Research supported in part by NASA grant NAGW-2329. We gratefully acknowledge MaryAnn Rounds and Deb Smart, Dept. of Food Science, Purdue Univ., for performing the seed composition analysis and Paul Williams, Dept. of Plant Pathology, Univ. of Wisconsin
C. A. Mitchell, H. C. Dostal, and T. M. Seipel
Brief, daily mechanical disturbance reduced dry weight gain as well as shoot elongation of tomato (Lycopersicon esculentum Mill. cv. Kokomo). Tactile (thigmo-) and vibrational (seismo-) stimulation of leaf surfaces increased leaf diffusive resistance and decreased transpiration in both stress-conditioned and unstressed control plants. The transitory nature of these responses suggests that prolonged reduction of stomatal aperture was not the cause of the dry weight or growth reductions. Changes in respiratory rates and photosynthetic efficiency also were ruled out. However, growth in dry weight paralleled increase in leaf area for stressed and unstressed plants, suggesting that reduced net photosynthesis was the result, rather than the cause, of retarded plant growth.
S. Hanif-Khan, P.J. Stoffella, J.K. Brecht, H.J. McAuslane, R.C. Bullock, C.A. Powell, and R. Yokomi
External and internal tomato irregular ripening (TIR) symptoms have been associated with the feeding of silverleaf whitefly (SLW), Bemisia argentifolii Bellows and Perring. Soil drench application of gibberellic acid (GA3) (100 ppm, Trial 1 and 2) and cycocel (CCC) (2000 ppm, Trial 1; 1000 ppm, Trial 2) were applied to dwarf cherry tomato (Lycopersicon esculentum) in the presence and absence of SLW to mimic the TIR disorder induced by the SLW. Application of GA3 induced external and internal TIR symptoms similar to the SLW-induced disorder in `Florida Petite'. There were essentially no TIR symptoms in fruit treated with CCC, an inhibitor of GA biosynthesis. In Trial 1, internal white tissue in GA3, SLW, and CCC treatments was expressed in 97%, 95%, and 4% of the total fruit, respectively. Incidence of external TIR symptom was highest (56%) in the GA3 plus SLW treatment. In Trial 2, GA3 application in the presence (83%) or absence (85%) of SLW resulted in the highest incidence of fruit with internal white tissue. External TIR symptoms induced by GA3 in the presence and absence of SLW were reduced with CCC application. These results suggest that the TIR disorder in tomato is induced by the SLW may be a GA3-regulated disorder.
Suxiao Hao, Yanfen Lu, Jing Liu, Yufen Bu, Qi Chen, Nan Ma, Zhiqin Zhou, and Yuncong Yao
concentrations of GA, resulting in dwarf phenotypes for both monocot and dicot plants; in turn, GA applications promote growth elongation ( Lohr et al., 2014 ). In the GA signal pathway, GIBBERELLIN INSENSITIVE DWARF1 (GID1) acts as the GA receptor, can combine