• Journal of Plant Biology
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• v.19 no.1
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• pp.14-18
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• 1976

Inhibition of flowering in Lemna perpusilla 6746 by 30 mM sucrose was reversed by the addition of acetylcholine (>$10^{-4}M) supplemented with 10^{-4}M$ ascorbic acid to 1/10-strength Hunter's growth medium. The reversible effect of acetylcholine was found to be greater at early stages of flowering than in the later period. Promotive effects of both acetylcholine ($10^{-3}M) and eserine(10^{-5}M$) on flowering in the short-day plant under various photoperiodic conditions were studied. It was indicated that the application decreased length of the critical dark period for the floral induction, and it was also shown that the endogenous status of acetylcholine was involved in the floral response which had a correlation with phytochrome. Interruption of inductive dark periods by red irradiation (1min) immediately followed by far-red light (1 min) completely inhibited flowering, while the addition of acetylcholine and eserine to the medium under the same condition slightly promoted flowering, indicating possible involvement of phytochrome system in acetylcholine activity for photoperiodic sensitivity of floral response in Lemna perpusilla 6746.

• Korean Journal of Weed Science
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• v.17 no.2
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• pp.207-213
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• 1997

This study was conducted to correlate changes in plant growth and flowering behavior with inhibition of gibberellin synthesis following application of GA biosynthesis inhibitor. Two sorghum genotypes, wild-type and phyB-1(phytochrome B mutant) which grow fast and flowers early relative to the wild-type, were used. Both growth and floral initiation of these two genotypes were greatly affected by ancymidol concentration increased. However, these growth inhibition and delayed flowering are almost completely overcome by simultaneous applications of 31.6ppm $GA_3$. The ability of $GA_3$ to reverse the effect of the inhibition on both growth and floral initiation in sorghum suggests a role for native GAs in sorghum flowering. This result was contrast to the fact that in some long day plants GA biosynthesis inhibitors will inhibit shoot elongation but not floral initiation. In sorghum, inhibition of vegetative growth by GA biosynthesis inhibitor is accompanied by a delay in flowering. Ten ppm of ancymidol treatments drastically reduced all early-13-hydroxylation pathway GAs($GA_{12}$, $GA_{53}$, $GA_{19}$, $GA_{20}$, $GA_3$, and $GA_8$) levels.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.2
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• pp.151-158
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• 1993

Since the inhibition of floral induction was considered to be an important subject to get high yield of Angelica gigas, the effects of low temperature, daylengh and shading were investigated in this study. The yield of A. gigas root grown by inhibition of floral induction was compared with the yield obtained by traditional cultivation method. When the seedings were exposed to the natural low air temperature condition until late of November, the plants which had 6 to 8 leaves showed vernalizing effect, and when the low temperature treatment was prolonged until mid of January, 4 to 5 leaf plants showed vernalizing effect. But 2 to 3 leaf plants did not show vernalizing effect regardless of the length of chilling treatment. The effectiveness of exposure to low temperature was markedly dependent upon the age of plants. In the artificial low temperature treatment the range of temperature varied with plant age. Vernalizing effect at 1,5 and 9$^{\circ}C$ of temperature did not show 3,5,6 leaf plants, respectively. The bolting percent in 8 leaf plant at 1,5 and 9$^{\circ}C$ for 8 weeks decreased by 80,45 and 5%, respectively. As daylength became longer, the bolting percent of A. gigas was increased. plants which were grown in the full sunlight showed the highest value in bolting percent, and the bolting percent was not decreased significantly with changing from full sunlight to 50% shading. When A. gigas were grown by the inhibition of floral induction, dry root weight per l0a showed the greatest value in 3 year old plant which 3.6 and 2.4 times higher than that of 1 and 2 year old plant, respectively. The yield of root was increased by 73.7% in 2 year old plant and 159.6% in 3 year old plant compared with the yield obtained by traditional cultivation method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.2
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• pp.71-76
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• 1998

To define the relations between endogenous GA levels and growth and flowering in short-day plant sorghum, growth retardant BX-112 was applied to two sorghum genotypes, wild-type and phytochrome B mutant (phyB-1), which grows faster and flowers earlier than the wild-type. BX-112 and $GA_3$ were applied as a soil drench, and plant height, culm length, and date to floral initiation were investigated. Endogenous GAs contents were measured with GC-MS-SIM. BX-112 treatments inhibited shoot growth in both genotypes and drastically reduced $GA_1$ and $GA_8$ levels. With increasing BX-112 concentrations, $GA_1$ concentrations declined linearly, but caused the accumulation of intermediates from $GA_12$ to $GA_20$. This result implies that $GA_1$ is the major active endogenous GA in shoot elongation in a short day plant sorghum. The inhibition of plant growth in both of wild type and phyB-1 by BX-112 was very similar, while BX-112 effects on floral initiation in two types of plants differed significantly. Floral initiation of phyB-1 was not affected by BX-1l2, but that of wild-type was delayed as BX-1l2 concentration increased. Because BX-112 treatment causes accumulation of biosynthetic intermediates between synthetic pathway from $GA_12$ to $GA_20$ and because phyB-1 is altered in GA metabolism in this same region of the early C13-hydroxylation pathway, BX-112 may fail to block flowering of phyB-1.

• Journal of Plant Biology
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• v.20 no.2
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• pp.77-82
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• 1977

The inhibiotory effect of ethphon on the flowering in Lemna perpusilla 6746 was shown to be related to sucrose concentrations and dilution factors of Hutner's medium. When grown in 1/10-strength Hutner's medium under 10(14) cycles, the plants have been completely inhibited in the floral induction by ethephon (>5ppm) in the presence of sucrose (>20 mM) in the meduim. However, in a less diluted Hutner's medium (1/2-strength), the inhibition of flowering by ethephon was observed to be partially diminished by sucrose at a high concentration (30mM), while a low concentration of sucrose enhanced the inhibitory effect of ethephon in flowering. As inductive dark periodswere extended, the effects of both compounds were partially nullified. Since no significant amount of ethylene possibly released in ethephon decomposition in the medium was detected, the inhibitory effect of ethephon in flowering was postulated to be exerted only through ethylene production within the plants. Plants were incubated in 10 ppm ethephon-containing medium during either dark or light periods, singly or periodically. The most effective single treatment with ethephon was observed during the 4th dark period, when formation of floral stimulus was assumed to be completed beyond a critical level. This postulation can be partially supported by a fact that the plants should be exposed to at least more than four consecutive 10(14) cycles for flowering.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.1-8
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• 1995

This study was carried out to investigate the effects of floral inhibition of An-gelica gigas NAKAI in the hilly altitude located in the Northern Gyeongbuk Province from Feb. 1992 to Nov. 1994. The results obtained were as follows ： As the cultivated areas are high, rate of bolting was significantly decreased, having high yield, good growth, and medicinal quality. It is considered that the optimal cultivating area was at least above 600m altitude. In the hilly altitude, the more shorten nursery period was, the more decreased rate of bolting was, it results in decreased yield, having no significant differences in contents such as extracts and decursin. In bolting response from temperature treatment of the seedlings, treatment of high temperature was significantly decreased floral induction, but rate of establishment was decreased by decayed root. Bolting rate at different organic resources has more reduced in single fertilization than that of in organic application, but among organic resources, compost of rice straw has the lowest bolting rate. As a result, yield and medicinal qualities at various organic resources were increased in application of organic resources which was no con-siderable tendency among organic resources.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.4
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• pp.317-323
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• 1993

In order to clarify the contents of active principles in floral inhibition cultured Angelica gigas roots, the amounts of crude extract and the contents of decursin and decursinol angelate in the yearly roots were analyzed and compared with respect to the root age, root part and growth stage. The woody cell, weight and width of pith and cortex were also investigated at different growth stage to observe the developmental characteristics of lignification in the roots as bolting and flowering in normal cultured Angelica gigas. The amount of crude extracts did not differ with plant ages, whereas the contents of decursin and decursinol angelate were differed and the highest in 3 year old roots. The contents of decursin in 1, 2 and 3 year old roots were 3.71, 4.76 and 8.20% and those of decursinol angel ate were 2.84, 3.40 and 5.01%, respectively. The amount of crude extracts, and the contents of decursin and decursinol angelate were the highest in fine roots, followed by the lateral roots and the lowest in the primary roots. On the other hand, the amount of the constituents in the cortex were much higher than those in the pith of the root. The amounts of crude extract, and the contents of decursin and decursinol angelate showed the highest value at the vagetative stage and decreased with development to bolting and blooming stage. Woody cells were accumulated in the pith of the root as advancing growth stage, so that the weight and radius of the pith increased, whereas the relative weight and width of the cortex decreased slightly.

• Journal of Photoscience
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• v.12 no.1
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• pp.1-9
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• 2005

The ubiquitin E3 ligase COP1 (Constitutive Photomorphogenesis 1) is a protein repressor of photomorphogenesis in Arabidopsisplants, and it found in various organisms, including animals. The COP1 protein regulates the stability of many of the light-signaling components that are involved in photomorphogenesis and in the developmental processes. To study the effect of COP1 on flowering in a short day plant, we have cloned a full-length of PnCOP1 (Pharbitis nil COP1) cDNA from Pharbitis nil Choisy cv. Violet, and we examined its transcript levels under various conditions. A full-length PnCOP1 cDNA consists of 2,280 bp nucleotidesthat contain 47 bp of 5'-UTR, 232 bp of 3'-UTR including the poly (A) tail, and 1,998 bp of the coding sequence. The deduced amino acid sequence contains 666 amino acids, giving it a theoretical molecular weight of 75 kD and a isolectric point of 6.2. The PnCOP1 contains three distinct domains, an N-terminal $Zn^2+$-binding RING-finger domain, a coiled-coil structure, and WD40 repeats at the C-terminal, implying that the protein plays a role in protein-protein interactions. The PnCOP1 transcript was detected in the cotyledon, hypocotyls and leaves, but not in root. The levels of the PnCOP1 transcript were reduced in leaves that were a farther distance away from the cotyledons. The expression level of the PnCOP1 gene was inhibited by light, while the expression was increased in the dark. During the floral inductive 16 hour-dark period for Pharbitis nil, the expression was increased and it reached its maximum at the 12th hour of the dark period. The levels of PnCOP1 mRNA were dramatically reduced upon light illumination. These results suggest that PnCOP1 may play an important function in the floral induction of Pharbitis nil.

• Korean Journal of Plant Resources
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• v.8 no.1
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• pp.55-62
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• 1995

This study was carried out to investigate the effects of floral inhibition of Angelica gigas NAKAI in the hilly altitude located in the Northern Gyeongbuk Province from Feb. 1992 to 1994. The results obtained were as follows: As the cultivated areas are high, rate of bolting was significantly decreased, having high yield, good growth, and medicinal quality. It is considered that the optimal cultivating area was at least above 600m altitude. In the hilly altitude, the more shorten nursery period was, the more decreased rate of bolting was, it results in decreased yield, having no significant differences in contents such as extract and decursin. In bolting response from temperature treatment of the seedlings, treatment of temperature was significantly decreased floral induction, but rate of establishment was decreased by decayed root. Bolting rate at different organic resources has more reduced in single fertilization than that of in organic application, but among organic resources, compost of rice straw has the lowest bolting rate. As a result, yield and medicinal qualities at various organic resources were increased in application of organic resources which was no considerable tendency among organic resources.

• Proceedings of the Korean Society of Crop Science Conference
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• 1994.06a
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• pp.104-105
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• 1994