• Journal of the Korean Society of Tobacco Science
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• v.11 no.2
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• pp.127-134
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• 1989

Several growth characteristics of two ornamental tobacco species, Nicotiana sanderae and N. affinis, were investigated in this study. Also effect of temperature and daylength on the flowering of the tobacco plants were evaluated to obtain basic information on breeding and cultivation. 1. The plants were great in high temperature-long day at the early stage and in low temperature-short day at the late stage of plant growth, for both Nicotana species. At the early growth stage the leaf length N. sanderae was great in high temperature-long day, and that of N. affinis was great in high temperature-short day period, while at the late stage of the plant growth the leaf lengths were more significantly effected by the temperature rather than daylength. Leaf width and leaf shape index were less sensitive to the conditions. 2. For both of the species, the total number of tobacco leaves not much influenced by the temperature and daylength. 3. There were no significant differences for budding and flowering period between the two species, both of which were sensitive to temperature and daylength with more influence by daylength than temperature. 4. Number of floral stalks, number of flower and flowering period were not much influenced by temperature and daylength; however, N. affinis had 2 more floral stalks, 31 more flowers, and 6 day longer flowering period than N. sanderae.

• Current Research on Agriculture and Life Sciences
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• v.31 no.1
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• pp.61-64
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• 2013

This study identified the effect of night time temperatures on the flowering period of spray-chrysanthemum during the summer season in South Korea. According to the results for 2005, the temperature at night time sustained more than $25^{\circ}C$ for 23.6 days during the short day period and delayed the flowering period for 22 days. Similar observations were reported in 2006, as the night time temperature sustained more than $25^{\circ}C$ for 23.6 days during the short day period and delayed flowering period for 23 days. The results for 2007 year showed that night time temperature sustained more than $25^{\circ}C$ for 31.9 days during the same period and delayed flowering for 31 days. In conclusion, based on the results for 2005 to 2007, a specific correlation was found between high night time temperatures and a delayed flowering period for the 'Euro' spray-chrysanthemum.

• Journal of Korean Society of Forest Science
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• v.96 no.2
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• pp.170-177
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• 2007

The objectives of this study were to select early, late, and abundant flowering trees of black locust from domesticated and introduced cultivars, and prediction of flowering period by calculation of accumulated temperature in spring. Four cultivars (Debreceni-2, Pusztavacs, Jaszkiseri, and Rozsaszin AC) from Hungary and a cultivar from Beijing, China, were introduced, propagated by seed and planted in a seed orchard. For domesticated black locust, 63 cultivars from 10 locations throughout the country were selected and propagated by root cutting. Criteria for selection of domesticated cultivars were abundant flowering, long flowering period, or abundant nectar production with, if possible, straight stems. Accumulated temperature was calculated from data of a nearby weather station by accumulating daily maximum temperature minus 5 degree Celsius from January 1 up to the date reaching 880 degrees. Daily mean temperature was also used to calculate accumulated temperature up to the date reaching 450 degrees. The percentages of two-year and three-year-old flowering trees propagated by root cutting were higher than that of trees propagated by seeds, while four-year-old trees all flowered regardless of propagation methods. Among the domesticated cultivars, all the cultivars from Ganghwa showed abundant flowering with highest nectar production of 6.5 ul per flower, which was 100% more than other domesticated cultivars and 50% more than Debreceni-2 cultivar with highest nectar production among the introduced cultivars from Hungary. At the end of the eight years of observations, two trees of Debreceni-2 cultivars and a tree from Beijing, China were selected for early flowering trees which flowered 2 to 3 days earlier than average trees, while a tree of Debeceni-2 and three trees from Bejing were selected for late flowering trees which flowered 2 to 3 days later than average trees. It is possible to extend the flowering period of black locust by 4 to 6 days by planting early and late flowering cultivars together. Abundant flowering trees were unable to be selected due to severe damages by leaf gall midges which killed many trees and reduced the crown size of the remaining trees in the seed orchard, and which were first found in Korea in 2001 and now damaging most of the black locust forests in Korea. The prediction of flowering period by accumulated temperature indicated that black locust flowered to a peak when accumulated daily maximum temperature reached 880 degrees Celsius, and when daily mean temperature reached 450 degrees.

• Journal of Ecology and Environment
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• v.47 no.3
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• pp.134-145
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• 2023

Background: The flowering and fruiting periods play an important role in biological processes. The deciduous dipterocarp forest is an important forest type in Thailand, however the phenological studies are still limited, particularly in different plant life forms. Thus, the present study focused on the flowering and fruiting phenology of herbs, climbers, shrubs, and trees in the deciduous dipterocarp forest at Lampang province of Northern Thailand. Field visits were made to record plant life forms and observe reproductive phenological events at monthly intervals from November 2018 to October 2019 and September to December 2020. Results: The phenological observations were based on 126 species of 45 families and 102 genera. Flowering and fruiting periods showed similar patterns in herbaceous plants, climbers, and shrubs. Most of these species produced flowers and fruits from the end of the rainy season (October) to the winter season (November-January). Whereas most of flowering and fruiting trees were found from the summer season (March-April) to the beginning of the rainy season (May-June). Most of the dry-fruited species occurred during the dry period (winter and summer seasons), while the majority of fleshy-fruited species dominated in the wet period (rainy season). The statistical analysis supported the phenological patterns of flowering and fruiting in the present study. There were significant negative correlations between the number of flowering and fruiting species and temperature. The number of flowering and fruiting species is significantly impacted by the interaction between seasons and plant life forms. Conclusions: Plant life form seems to be the important factor that affects the different phenological patterns in the studied plants. The abiotic and biotic factors play major roles in reproductive phenology. However, long-term study and in-depth phenological observations are necessary for better understanding.

• Korean Journal of Environment and Ecology
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• v.31 no.6
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• pp.564-577
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• 2017

We investigated whether external environmental factors acted as a trigger for flowering in the draft bamboo (Sasa borealis (Hack.) Makino) blooming area of Mt. Baekwoon located in Gwangyang, South Jeolla Province. We then considered the cause for flowering, flowering patterns and life history strategies of the draft bamboo based on the investigation. There were no differences in soil, physical conditions, and light amount between the draft bamboo flowering and non-flowering areas. The precipitation and temperature of the areas in Korea and Japan where it blossomed from 2014 to 2017 were similar to the normal year values (for the past 30 years). Moreover, most of the draft bamboo died after flowering on a large scale, but some did not, or some culms were developed again. In other words, the draft bamboo bloomed simultaneously regardless of external environmental factors, and most of the culms were dead, but some were left alive. Therefore, it is considered that the flowering is triggered by the specific genes (referred as to clock genes) expressed periodically by a biological clock rather than the external environmental factors. Meanwhile, the draft bamboos generally bloom on a large scale by synchronizing with other ones in the distance but may also bloom several times separately on a small scale. It may be a kind of an insurance system established to disperse the risk of failed sexual propagation when flowering once in a lifetime. The results reveal that the long-period monocarpy of the draft bamboo has been strengthened to optimize the sexual propagation to overcome the increased environmental instability caused by the expansion of distribution of tropical bamboos and bamboo species to the temperate regions.

• Proceedings of the Botanical Society of Korea Conference
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• 1987.07a
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• pp.191-211
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• 1987

Common usage of the concept of juvenility implies that there is one physiological phase, the juvenile phase, which manifests itself in the various morphological and physiological phenomena observed in juvenile higher plants. The juvenile phase is often defined as that time from seed germination until the plant attains the ability to flower regulating such behaviour. This definition precludes plants from flowering in the juvenile phase. It is of major interest, therefore, to identify the physiological controls(Bluehreife) regulating such behavior. The length of the juvenile period in higher plants ranges from one year to over 60 years in different species. The long juvenile period of seedling is the main cause of the long duration of the breeding process. I determined the length of the juvenile period in various plants and its control of phase changes in natural system in relation to factors such as plant size and age, shoot morphology, apex size, root system and phytohormonal and nutritional status is reviewed. From the own experimental and observational evidence available it appears that both hormonal and nutritional factors can be involved in control of juvenility but that a specific juvenile or flowering hormone is not involved. Grafting, ringing, scoring, root pruning and fertilization have been used to accelerate flowering, but in most cases these cultured treatments are only successful on plants that were passed the juvenile phase. It is suggested that there are intrinsic difference between the meristematic cells of the apieces of juvenile and adult shoot, which are thus determined with respect to there development potentialities. The problems associated with the maintenance of the determined state through mitosis are discussed. The properties of transitional forms of Ribes nigrum L. intermediate between the juvenile and adult phase, are descrived and there implications discussed. Analogies are drawn between juvenile phenomena in woody perennials and in herbaceous species.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.133-137
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• 1973

In order to classify the ecotypical and maturing groups 136 Korean local and 4 Japanese Perilla varieties were sown at Suwon on May 20, 1972, and investigations were made on days to flowering, days to maturing and growth duration. Results obtained were summarized as follows: 1. Ecotype was classified from 6 groups with combination of the long and short duration from sowing to flowering and maturing period. The classified symbols of groups were Ia, Ib, IIa, IIIa, and IIIb. I: long duration. to flowering II: medium duration to flowering III: short duration to flowering a: long duration to maturing b: short duration to maturing Korean local varieties were distributed 3 ecotypes of IIa, IIb and IIIa, however, Japanese varieties did 2 ecotypes of IIa and IIb, respectively. 2. Maturing group was classified from 3 groups with long (I), medium (II), and short (III) growth durations. Korean local varieties belong to II and III groups but Japanese varieties belong to I and II groups, respectively. 3. Three were highly significant positive correlation (0.685) between ecotypical and maturing group. Ecotype was more related with days to flowering and growth duration, however, maturing group was related with days to flowering, days for maturing, and growth duration. Korean local varieties, more distributed into ecotype than maturing group, were attributed to differences of environmental conditions and cultural practices at different provinces.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.1
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• pp.55-70
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• 2001

It was unusual crop weather for 1998 and 1999 compared with normal in Korea. The consecutive days of the optimum ripening period for rice plant that had daily mean temperature 21~23$^{\circ}C$ for 40 days after flowering, increased with long anomalies in 1998~99. The air temperature during ripening period was much higher than the optimum temperature and lower sunshine hour than norm in the local adaptability tests of newly developed rice lines during those years. In response of rice cultivation to warming and cloudy weather during crop season, the yield shall be decreased. Most scientists agree that the rate of heating is accelerating and temperature change could become increasingly disruptive. Weather patterns should also become more erratic. Agrometeorologists could be analyzed yearly variations of temperature, sunshine hour and rainfall pattern focused on transient agroclimate change for last a decade. Rice agronomists could be established taking advantage of real time agricultural meteorology information system for fertilization, irrigation, pest control and harvest. Also they could be analyzed the characteristics of flowering response of the recommended and newly bred rice cultivars for suitable cropping plan such as cultural patterns and sowing or transplanting date. Rice breeders should be deeply considered introducing the characteristics of basic vegetative type of flowering response like Togil rices as prospective rice cultivars corresponding to global warming because of the rices needed higher temperature at ripening stage than japonica rices, photoperiod-sensitive and thermo-sensitive ecotypes.

• Horticultural Science & Technology
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• v.34 no.2
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• pp.207-219
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• 2016

Incandescent (INC) lamps have been commonly used to promote flowering of long-day (LD) plants during short-day (SD) seasons, but production of INC lamps has been prohibited due to their low energy efficiency. One of the light sources replacing INC lamps is a compact fluorescent lamp (CFL). This study was carried out to compare the flowering and morphological responses of LD annuals grown in a controlled environment greenhouse at $20^{\circ}C$ with a truncated 9-h SD and a 2- or 4-h night interruption (NI) or 6-h day extension (DE) provided by lighting from INC lamps, CFLs, or a combination of the two (INC + CFLs), in which red (R) to far-red (FR) ratios were 0.60, 8.46, and 0.91, respectively, and their PPFDs were $2.3{\pm}0.3{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. After 12 weeks of treatment, $Petunia{\times}hybrida$ 'Wave Purple' plants did not flower under the SD photoperiod whereas 100% flowered under all of the LD treatments. Flowering was more rapid under the INC or INC + CFL lighting treatments compared to CFL and DE, and 4-h NI enhanced flowering compared to 2-h NI. In addition, plants under DE and 4h-NI generally flowered earlier than under 2-h NI. All petunia 'Single Dreams Red' plants flowered within 65 days after treatment, and flowering was hastened by some LD lighting regimens and lamp types. Plants under DE and 4h-NI generally flowered earlier than under 2-h NI INC or INC + CFL compared to FL, and flowering time under INC 6-h DE was earliest. In addition, INC lighting promoted stem elongation of both petunia cultivars. In both pansy (Viola${\times}wittrockiana$) 'Coiossus Yellow' and 'Delta Blue Blotch', LD treatments, especially using INC lamps, promoted flowering whereas the lighting period had little influence on days to flowering. Therefore, INC or INC + CFL with lower R:FR promoted flowering and stem extension and the promoting effect was larger with longer lighting periods. These results suggest that CFLs can be used to provide LDs to promote the flowering of petunia and pansy and to reduce stem elongation, although the promoting effect on flowering is sometimes less than that of INC lamps alone.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.1
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• pp.22-29
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• 2020

Rice is very sensitive to high temperatures during the reproductive stage, particularly during the flowering and anthesis periods. To determine how high temperatures result in sterility during the flowering period in Korean rice cultivars, groups of 11 cultivars were subjected to different temperature regimes (24, 28, 30, and 33℃) during the flowering stage using sunlit phytotrons. At an average of 33℃, all 11 rice cultivars reached anthesis earlier than at the other temperatures. Microscopy analyses revealed significant differences in pollen germination and pollen viability in cultivars grown at 33℃ compared to those cultured at lower temperatures. At 33℃, the cultivars had significantly lower fertility rates (47% reduction) than cultivars grown at 24℃. These findings are important as rice pollination and fertility depend on the pollen viability and germination. The present study shows that rice fertility is negatively affected by excessively high temperatures.