THE EFFECTS OF PHOTOPERIOD, TEMPERATURE, AND LIGHT INTENSITY ON THE GROWTH OF THE LOWBUSH BLUEBERRY (VACCINIUM ANGUSTIFOLIUM AIT.)

1961 ◽  
Vol 39 (7) ◽  
pp. 1733-1739 ◽  
Author(s):  
I. V. Hall ◽  
R. A. Ludwig

A study of the effect of environmental factors on the growth and development of the lowbush blueberry was carried out using clonally propagated plants. In a preliminary study a definite photoperiodic response was found. Under 8-hour days flower buds were formed and no vegetative growth occurred. Under 16-hour days vegetative growth resulted and no flower bud formation occurred. In a replicated greenhouse experiment, seven clones produced flower buds with 8-, 10-, and 12-hour days, but produced none with 14- or 16-hour days. One clone produced flower buds with 8-, 10,- 12-, and 14-, but none with 16-hour days. Two clones were able to produce flower buds under all five photoperiods. Under 8- and 10- hour photoperiods no vegetative growth occurred. Under 12, 14, and 16 hours progressively more vegetative growth occurred. In an experiment on the interaction of temperature and photoperiod, vegetative growth was significantly greater at 70° F than at 50° F with the differences being accentuated by day length. Flower bud formation occurred with 11- and 13-hour photoperiods regardless of temperature, but was more pronounced at the higher temperatures. At 70° F, 15-hour photoperiod, no flower buds were formed while at 50° F, 15 hours, three clones produced no flower buds and six clones produced an abnormal type of inflorescence. Similar abnormal inflorescences were produced by giving plants 2, 3, or 4 weeks of 8-hour days. Six weeks of 8-hour days was sufficient to initiate normal inflorescences. Shade, provided by two layers of cheesecloth, significantly reduced the number of flower buds compared with full sunlight. The growth of the lowbush blueberry under field and laboratory conditions is discussed in relation to environmental factors.

2013 ◽  
Vol 36 (1-2) ◽  
pp. 83-94 ◽  
Author(s):  
Franciszka Jaumień

The growth of trees sprayed in spring with chlormequat is weaker, and their elongation growth ends 2 - 3 weeks earlier than that of unsprayed trees. Trees with growth inhibited by chlormequat set flower buds on the spurs and in the subapical part of long shoots. The course of flower bud differentiation starts in the second half of July and is similar to that in the apple tree.


1993 ◽  
Vol 71 (5) ◽  
pp. 732-736 ◽  
Author(s):  
Olle Kellner

A population of Pulsatilla vernalis (L.) Mill, was studied in permanent plots for 8 years. Half the plots were fertilized with ammonium nitrate (15 g N/m2) at the start of the study. Mortality and natality in the ramet population were very low in both fertilized and control treatments. In contrast, there was a considerable between-year turnover of shoots within ramets in both treatments. The number of shoots increased threefold after fertilization and then gradually decreased to the original level. Flower-bud formation in unfertilized plots was lower in warm and dry years than in cooler, wetter ones. In fertilized plots, flower-bud formation was higher after fertilization irrespective of the climate at the time. The proportion of flower buds grazed was higher in fertilized plots. Even though the species is confined to nitrogen-poor habitats, a single fertilization did not adversely affect its performance. Key words: Pulsatilla vernalis, population dynamics, nitrogen, weather, forestry.


1982 ◽  
Vol 62 (3) ◽  
pp. 823-826 ◽  
Author(s):  
A. ALI ◽  
V. SOUZA MACHADO

In field conditions, rutabaga (Brassica napus ssp. Rapifera (Metzg.) Sinsk.) plants are biennials and require exposure to low temperature for completion of their life cycle to seed production state. When young rutabaga plants were thermoinduced (3–5 °C) for 8 wk and subsequently transferred to growth room conditions, formation of flower buds resulted in 6 wk. Flowering response was greatly enhanced if the plants were sprayed with GA3 (100 mg/L) prior to thermoinduction. Compared with untreated plants, the GA3-sprayed plants responded with flower bud formation after as little as 3 wk of cold treatment. A longer cold exposure (6–8 wk) of the GA3-sprayed plants resulted in rapid development and maturity of the inflorescence. This note emphasizes the pharmacological role of gibberellins as regulators of flowering and their usefulness to enhance seed production and plant breeding programs.


HortScience ◽  
1992 ◽  
Vol 27 (7) ◽  
pp. 783-785 ◽  
Author(s):  
Paul M. Lyrene

Vigorous, upright shoots on mature V. ashei Reade cv. Aliceblue plants growing in a commercial field planting were used to study the effects of premature defoliation on flower bud formation. Three treatments (total shoot defoliation, alternate-node defoliation, and no defoliation) were applied on each of three dates (20 Aug., 17 Sept., and 15 Oct. 1987). For the August defoliation, the number of flower buds present per shoot on 6 Jan. of the following year averaged 1.3 for shoots that were totally defoliated, 3.7 for shoots on which alternate nodes had been defoliated, and 4.2 for control (nondefoliated) shoots. Shoots treated on 17 Sept. averaged 2.6 buds per shoot for total defoliation, 4.1 for alternate-node defoliation, and 4.8 for controls. Defoliation on 15 Oct. did not reduce flower bud formation. Reduction in flower bud formation due to defoliation was localized at the defoliated nodes. For shoots on which alternate nodes were defoliated on 20 Aug., 59.8% of the apical five nodes that were not defoliated produced flower buds compared with 1.4% of the defoliated nodes.


HortScience ◽  
2014 ◽  
Vol 49 (4) ◽  
pp. 516-518 ◽  
Author(s):  
Fumiko Ishizuna ◽  
Nobuhiro Tsutsumi

The genus Nelumbo consists of two species, N. nucifera and N. lutea. N. nucifera is an ornamental and edible plant that is widely cultivated. Earlier studies of sacred lotus (N. nucifera) flowers focused mainly on morphology, phyllotaxis, leaf arrangements, and flower development. During the growing season, sacred lotus produces one foliage leaf at each node. Flower buds emerge from the abaxial side of the basal part of the foliage leaf. However, the number of blooming flowers is much less than the number of foliage leaves. Little is known concerning flower bud formation during lotus plant development. This is the first experimental study to reveal that every node has one flower bud even in the dormant shoot apex and that most of the formed flower buds aborted in the course of floral development. Our results suggest that flower bud formation of sacred lotus is independent of daylength. On the other hand, whether a formed bud reaches blooming may depend on environmental factors.


Author(s):  
Nezihe Köksal ◽  
Sara Yasemin ◽  
Aslıhan Özkaya

Photoperiod is one of the environmental signals that controls of the flowering time on bedding plants. Marigold is a bedding plant which includes obligate or facultative short day and day neutral cultivars. Flowering time of these plants, even day neutral cultivars, delay in extreme hot and long day condition in summer. In this study, the effects of photoperiodic conditions (short day and long day) on flowering and growth of two different day neutral marigold cultivars (Discovery Orange and Discovery Yellow) were investigated. Natural day length (14 hours) was considered as long day condition. Short day condition (8 hours) was conducted artificially by darkening treatment. Therefore, duration to first flower bud formation, duration to first flowering, plant canopy height, plant canopy width, lateral branch number, flower number, main peduncle length, main peduncle thickness, root collar thickness, stem thickness, dry weights of plants (root, shoot, total plant) were evaluated. At the end of the experiment, it was determined that short day conditions reduce duration to first flower bud formation and duration to first flowering. The artificial short day conditions resulted as 13 days early flowering in 'Discovery Orange' and 5 days early flowering in 'Discovery Yellow' cultivar.


1995 ◽  
Vol 43 (2) ◽  
pp. 151-157 ◽  
Author(s):  
Yitzchak Gutterman

Opuntia ficus-indica(prickly pear) is a widespread desert perennial cactus shrub. The plants produce either lateral branches or flowers from the axillary meristems, depending on maternal and environmental influences.The flower buds develop from the axillary meristems mainly at the margin of the apical part of the terminal flat branch segments. Flower bud meristems start to be active and secrete mucus in January. The red-bracted flower buds start to appear in March/April, flowers open in May/June, and fruit matures in June/August.This study focused on the appearance of flower buds, flowers, and fruits after induction ofO. ficus-indicaone-segment branch cuttings by environmental factors during the 3-week healing period after cutting and before planting. The influence of treatments such as temperature, light intensity, and day length on flower bud appearance and fruit development is described.


HortScience ◽  
1991 ◽  
Vol 26 (5) ◽  
pp. 482c-482
Author(s):  
Duane W. Greene

The trend toward planting high density apple orchards continues. Closer tree spacing requires a greater degree of growth control to reduce shading and to prevent the decline in fruit quality and productivity as the planting become older. Chemical, rootstock, pruning, and management techniques will be reviewed that may control growth directly by reducing vegetative growth or indirectly through effects on increasing flower bud formation and fruit set. Pruning and management techniques will be discussed that can selectively reduce vigor in the tops of trees while allowing growth of the less vigorous lower portion of a trees to continue.


HortScience ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 523-526 ◽  
Author(s):  
Seong-Tae Choi ◽  
Doo-Sang Park ◽  
Seong-Mo Kang

Heavy pruning to lower tree height of persimmon results in excessive production of water sprouts and reduced yield. This experiment was conducted on ‘Fuyu’ (Diospyros kaki) trees to assess if the time for terminal bud set of water sprouts affected flower bud formation. Some sprouts were not pruned to serve as fruiting branches for the next season. Thirty to 40 water sprouts were tagged in 2005 and 2006, the growth of which stopped from mid-June to late August. The later terminal buds set, the lower the percent dry weight in the apical 10 cm. The apical segments of sprouts that continued to grow to mid- to late August were characterized by low soluble sugars, starch, and inorganic elements such as nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) compared with those that set terminal buds earlier. The number of flower buds from the water sprouts that set terminal buds by early August the previous year bore more than 12 flower buds the next year, whereas those that grew to mid- to late August bore fewer than three. It was concluded that water sprouts could be used as fruiting branches for the next year as long as terminal buds set by early August, thereby alleviating yield reductions that come with heavy pruning.


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