• Journal of Ecology and Environment
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• v.31 no.2
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• pp.153-159
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• 2008

The timing of the canopy phenology onset (CPO hereafter) indicates the initiation of the growing season, with rapid increases in exchange rates of carbon dioxide and water vapor between vegetation and atmosphere. The CPO is regarded as a potential indicator of ecosystem responses to global warming, but the CPO shows considerable spatial variation depending on the species composition and local temperature regime. at a given geographic location. In this study, we evaluated the utility of satellite observation data for detection of the timing of the CPO. Leaf area indices (LAI) obtained from the Moderate Resolution Imaging Spectrora-diometer (MODIS) were utilized to detect and map the onset dates from 2001 to 2006. The reliability of MODIS-based onset dates was evaluated with ground measured cherry blossom flowering data from national weather stations. The MODIS onset dates preceded the observed flowering dates by 8 days and were linearly related with a correlation coefficient of 0.58 (p < 0.05). In spite of the coarse spatial (1 km) and temporal (8 days) resolutions of MODIS LAI, the MODIS-based onset dates showed reasonable ability to predict flowering dates.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.1
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• pp.1-11
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• 2007

Light is an environmental component inevitably regulating photosynthesis and photo-morphogenesis, which are involved in the plant growth and development. Studies were conducted at the International Rice Research Institute, Philippines in 2004 and 2005, with aims to investigate 1) morphological responses of rice plants to low radiation, 2) morphological alteration of shade-grown plants when exposed to high light intensity, and 3) photosynthetic responses of shade-grown rice plants. Reduction in solar radiation by 40% induced increases in the area on a single leaf basis, biomass partitioning to leaves, and chlorophyll meter readings but brought about retardation of tiller development and decrease in above-ground biomass production of rice varieties. When the shade-grown plants from two weeks of transplanting to panicle initiation were exposed to full solar radiation after panicle initiation, they demonstrated less increase in chlorophyll meter readings and more decrease in leaf nitrogen concentrations from panicle initiation to flowering than control plants that were grown under the ambient solar radiation for whole growth period after transplanting. Shade-grown rice plants exhibited lower carbon assimilation rates but higher internal $CO_2$ concentrations on a single leaf basis than control plants, when measurements for shade-grown rice plants were made under the shading treatments. But when the measurements for shade-grown plants were made under the full solar radiation, light-saturated carbon assimilation rates were similar to control plants. Response of photosynthetic rates to varying light intensities was not considerably different between shading treatments and control. Yield reduction was observed in the shading treatments from panicle initiation to flowering and from flowering to physiological maturity, mainly by less spikelets per panicle and poor grain filling, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.8
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• pp.1192-1199
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• 1999

Two cultivars of subterranean clover (Trifolium subterraneum L.), "Dinninup" and "Seaton Park" were sown at Shenton Park Field Station, Western Australia, in May 1992 and 1993. The characteristics of Dinninup related to animal production were compared with Seaton Park under grazing conditions with herbage utilization efficiencies of 60% in 1992 and 65% in 1993. The results showed that Dinninup and Seaton Park had similar dry matter digestibility (77-78%) and dry matter production (1,290 kg/ha in 1992; 930 kg/ha in 1993) before flowering initiation even though Dinninup had more (p<0.05) branches, leaves and petioles per plant. After flowering, the herbage on offer of Dinninup was higher (p<0.05) and dry matter digestibility was lower (p<0.05) than that of Seaton Park while the sward structure was similar for both cultivars. The variation in nutritive value among plant parts increased with maturation. Leaf was more digestible than stem and petiole with a higher nitrogen content, and stem had the lowest dry matter digesitibility and nitrogen content in late of the season. Sheep did not show any preference for Seaton Park over Dinninup. The predicted bodyweight gain of sheep grazing pure Seaton Park and Dinninup swards using Grazfed software indicated that sheep grazing Dinninup were predicted to have a similar bodyweight gain in early growing stage and a significantly lower gain after flowering compared with those grazing Seaton Park.

• Journal of Korean Society of Forest Science
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• v.33 no.1
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• pp.59-67
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• 1977

Seasonal changes in free arginine concentration in Pinus radiata buds were studied in four clones from May, 1974 to June, 1975. The buds were from the tips of first order branches which had flowered the previous year, and the significant findings were as follows: (1) In general, arginine concentration in the buds of the four clones showed the highest peaks from December to March, a period spanning the time of flower initiation, and the lowest levels in Angust and September. (2) The timing of individual arginine peaks during the period of flower initiation matched roughly the timing of initiation of several female cone clusters, as determined from Clone 7 which characteristically initiates three cycles of female cones on its leading shoot. (3) The heavy-flowering clones showed higher arginine concentration than ther poorer flowering ones, especially at the time of flower initiation.

• Journal of Korean Society of Forest Science
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• v.47 no.1
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• pp.16-26
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• 1980

Soluble carbohydrates and free amino acids in the terminal buds of Pinus elliottii were analyzed to understand the nutritional status of the buds during the period of female strobilus initiation. Grafted, 18-year-old slash pine trees in a seed orchard were divided into two groups, abundant-flowering (AFG) and poor-flowering group (PFG) according to their flowering history. Four types of terminal buds, with two types from each group, were examined: (1) large buds in upper crown (female-producing buds) and small buds in lower crown (male-producing) in AFG, (2) large buds in upper crown (vegetative buds) and small buds in lower crown (male-producing) in PFG. Bud samples were collected four times from late July to early September. Free sugars and free amino acids (75% ethanol-soluble) were determined by gas chromatography and automatic analysis, respectively. Sugar content in the large buds of both groups was greater than in the small buds of the same group. Fructose and glucose were major sugars found in the bud tissue. Arginine was the most abundant amino acid in all four types of buds, with the concentration increased from 23% in late July to 60% in early September. Arginine and total amino acid content in the female-producing buds of AFG was much lower than three other types of buds. When female-producing buds and male-producing buds of AFG were compared in their arginine content, the former contained about same amount as the latter in late July, but showed one-fourth of the latter in early September. The low level of argining in the female-producing buds suggested a minimal or negative role of arginine in the initiation of female flower primordia. A higher sugar to amino acid ratio was observed with female-producing buds of AFG than with vegetative or male-producing buds of either flowering group. The low amino acid content in the female­producing buds suggested that initiation of female strobilus primordia was associated with temporary reduction in the metabolic activity of the buds.

• Journal of Korean Society of Forest Science
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• v.46 no.1
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• pp.21-28
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• 1980

Strobilus initiation in grafted, 18-year-old slash pine (Pinus elliottii var. elliottii) in a seed orchard was examined in relation to morphological and anatomical characteristics of shoots. Needle weight (total fresh weight of needles per shoot produced during the current growing season) was the most closely related single variable to the number of female flowers produced the following year ($R^2=0.41$). The number of female and male strobili (per shoot) produced the following year was positively and negatively correlated, respectively, with the total weight of current-year needles per shoot. A transition from male to female flowering was associated with increasing vigor (number of needles) of the shoot. Vegetative buds in the upper parts of the crown of poor-flowering trees showed more advanced growth of vascular tissues compared with female-or male-producing buds, indicating a strong favor for vegetative growth.

• Horticultural Science & Technology
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• v.29 no.2
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• pp.135-143
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• 2011

In the Doritaenopsis hybrid, like most of the orchid species and hybrids, temperature is crucial for the vegetative-to-reproductive transition, and low temperature is required for bud differentiation. To understand the molecular mechanism of this process, an orchid GIGANTEA (GI) gene, DhGI1, was isolated and characterized by using the rapid amplification of cDNA ends (RACE) PCR technique. Sequence analysis showed that the full-length cDNA is 4,022 bp with a major open reading frame of 3,483 bp, and the amino acid sequence showed high similarity to GI proteins in Zea mays, Oryza sativa, Arabidopsis thaliana and other plants. Semi-quantitative RT-PCR revealed that DhGI1 was expressed throughout development and could be detected in roots, stems, leaves, peduncles and flower buds. The expression level of DhGI1 was higher when the plants were flowering at low temperature (22/$18^{\circ}C$ day/night) than the other growth stages. Further analysis indicated that the accumulation of DhGI1 transcripts was significantly increased at low temperature, and concomitantly, initiation of the peduncle was observed. However, DhGI1 levels were low under high temperature (30/$25^{\circ}C$) conditions, and flower initiation was inhibited. These results indicate that the expression of DhGI1 is regulated by low temperature and that DhGI1 may play an important role in inflorescence initiation in this Doritaenopsis hybrid at low temperatures.

• Journal of Korean Society of Forest Science
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• v.59 no.1
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• pp.31-36
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• 1983

Flowering time of Pinus rigida Mill and Pinus taeda L, in an $F_1$-hybrid seed orchard was investigated for five years from 1971 through 1975. The two tree species flowered during late April to early May at the observation site, Flowering patterns of the two species of different sex of the same species changed yearly during the five observation years. Floral development of the two species appeared to depend largely on temperature factor during the period of the initiation of floral organs up to flowering provided that other environmental factors are normal. Six-days difference in flowing time between female inflorescence of pitch (flower later) and male inflorescence of loblolly (flower earlier) pines effectively isolated the two species reproductively on population levels. Not all of selected trees of the two species for their synchronized flowering appeared to be useful as parental trees for the establishment of $F_1$-hybrid seed orchards. With the result from this investigation the author suggested to use a modified simple recurrent selection method for pitch-loblolly hybrid pine breeding.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.2
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• pp.51-55
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• 1979

The effects of vernalization and darkness on flower initiation were reviewed by using naked barley varieties. The dark effects were pronounced on flower induction even at 25$^{\circ}C$. There were no differences in flowering responses among varieties. The effects of vernalization and darkness combined with 25$^{\circ}C$were 100% and 60% respectively which showed a significant difference. When the alternation of darkness with light was taken as first and last the flowering rate was 92 percent. When it was intercalated by light treatments the flowering rate was 91 per cent. Thus the effects of vernalization and darkness seems to differ.

• Korean Journal of Plant Resources
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• v.14 no.2
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• pp.163-168
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• 2001

This study was conducted to obtain basic information on cross breeding for developing bolting resistant variety of Angelica gigas NAKAI which has been subjected to severe yield reduction resulted from flower-stalk initiation during the growth. Compatibility of selfing and/or crossing pollination among 5 local cultivars were tested. Results obtained are summarized as follows. In case of three year old plant, all cultivars emerged March 14 and bolted from May 12 to May 13. Ponghwa cultivar was flowered 3 to 5 days earlier than other cultivars. Flower duration continued 41 to 43 days. Interval of flowering date from main stem to first primary branch, from first to second or second to third primary branch was 9 to 13 days. Emergency of stamen proceeded 4~8 days of pistil initiation demonstrating that Angelica gigas NAKAI is protandrous plant. Furthermore initiation of first pistil was 1~4days later than formation of last stamen in the same flower cluster. Percent pollination of Angelica gigas NAKAI was 52% under natural condition, so called open-pollination, but bagging by enveloping flowers was as low as 0.4~2.4%. In the result of compatibility test, all local cultivars tend to show both of self-and cross-compatibility. Inpollination, ‘Muju’$\times$‘Muju’combination showed highest fertility up to 40.8% whereases cross pollination, ‘Pyeongchang’$\times$‘Inje’combination, showed 67.0% fertility.