• 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.

• BMB Reports
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• v.40 no.2
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• pp.247-260
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• 2007

Cinnamate 4-hydroxylase (C4H) is a key enzyme of phenylpropanoid pathway, which synthesizes numerous secondary metabolites to participate in development and adaption. Two C4H isoforms, the 2192-bp BnC4H-1 and 2108-bp BnC4H-2, were cloned from oilseed rape (Brassica napus). They both have two introns and a 1518-bp open reading frame encoding a 505-amino-acid polypeptide. BnC4H-1 is 57.73 kDa with an isoelectric point of 9.11, while 57.75 kDa and 9.13 for BnC4H-2. They share only 80.6% identities on nucleotide level but 96.6% identities and 98.4% positives on protein level. Showing highest homologies to Arabidopsis thaliana C4H, they possess a conserved p450 domain and all P450-featured motifs, and are identical to typical C4Hs at substrate-recognition sites and active site residues. They are most probably associated with endoplasmic reticulum by one or both of the N- and C-terminal transmembrane helices. Phosphorylation may be a necessary post-translational modification. Their secondary structures are dominated by alpha helices and random coils. Most helices locate in the central region, while extended strands mainly distribute before and after this region. Southern blot indicated about 9 or more C4H paralogs in B. napus. In hypocotyl, cotyledon, stem, flower, bud, young- and middle-stage seed, they are co-dominantly expressed. In root and old seed, BnC4H-2 is dominant over BnC4H-1, with a reverse trend in leaf and pericarp. Paralogous C4H numbers in Brassicaceae genomes and possible roles of conserved motifs in 5' UTR and the 2nd intron are discussed.