A cell suspension culture of Panax ginseng which may be continuously subcultured has been established. Embryogenic callus derived from clutured young leaves was used to initiate the culture.Plant growth regulators, ba...A cell suspension culture of Panax ginseng which may be continuously subcultured has been established. Embryogenic callus derived from clutured young leaves was used to initiate the culture.Plant growth regulators, basal medium formula and carbohydrate levels were examined to determine their various effects on suspension culture cell growth and development. The best selection of plant growth regulator, hasal medium and carbohydrate level is 2 mg / L 2,4-D: 0.5 mg / L KT,MS and 3% sucrose respectively.展开更多
Boron is an essential nutrition for higher plants. However, the primary function of boron remains a matter of discussion. Boron may function by forming complexes with compounds having cis \|hydroxyl groups(diols), ...Boron is an essential nutrition for higher plants. However, the primary function of boron remains a matter of discussion. Boron may function by forming complexes with compounds having cis \|hydroxyl groups(diols), e.g., pectic materials in cell walls, glycoproteins or glycolipids in membranes and o \|diphenols. The well\|defined functions of boron are its involvement in maintaining cell wall structure and both the structural and the functional integrity of plasma membrane. Lack of boron causes an increase in the leakage of ions and compounds which reflects the impairment of plasma membrane. Boron is functionally important in forming a pectic network in cell wall which is responsible for the extensibility of cell wall and consequently regulates cell growth.展开更多
Azospirillum brasilense is a well known plant growth-promoting rhizobacterium. Plant cell growth is constrained by the primary cell wall (CW) which contains polysaccharide-bound hydroxycinammic acids (HCAs). They deri...Azospirillum brasilense is a well known plant growth-promoting rhizobacterium. Plant cell growth is constrained by the primary cell wall (CW) which contains polysaccharide-bound hydroxycinammic acids (HCAs). They derive from phenylpropanoid metabolism, which first step is the reaction catalyzed by phenylalanine ammonia-lyase (PAL;EC 4.3.1.24). Also CW peroxidases (FAPOD;EC 1.11.1.7) play a key role in the stiffening of the CW, and in the cessation of cell elongation. Knowledge of the biochemical effects the bacteria could elicit into plant CW and how these responses could change the hypocotyl physiology still remains scarce. The objective of this work was to unravel the effects of A. brasilense Sp245 inoculation on HCAs of the primary CW in apical and basal segments of cucumber seedlings hypocotyls. Azospirillum inoculation increased hypocotyls’ length. Transferulate and p-coumarate were the major HCAs. Dimmers were detected only in the basal region of 13- and 15-d-old hypocotyls. The ratio t-ferulate/dimmer (an inverse index of CW cross-linking) was five times higher in inoculated seedlings. Enzyme activities determined were not directly involved in HCAs content changes. It was previously reported that the CW was a target for A. brasilense growth promotion. This work corroborates that the phenolics, FA, DFA, and p-coumarate bound to the CW are also involved in Azospirillum plant growth promoting strategies.展开更多
Root hairs and pollen tubes are formed through tip growth, a process requiring synthesis of new cell wall material and the precise targeting and integration of these components to a selected apical plasma membrane dom...Root hairs and pollen tubes are formed through tip growth, a process requiring synthesis of new cell wall material and the precise targeting and integration of these components to a selected apical plasma membrane domain in the growing tips of these cells. Presence of a tip-focused calcium gradient, control of actin cytoskeleton dynamics, and formation and targeting of secretory vesicles are essential to tip growth. Similar to cells undergoing diffuse growth, cellulose, hemi-celluloses, and pectins are also deposited in the growing apices of tip-growing cells. However, differences in the manner in which these cell wall components are targeted and inserted in the expanding portion of tip-growing cells is reflected by the identification of elements of the plant cell wall synthesis machinery which have been shown to play unique roles in tip-growing cells. In this review, we summarize our current understanding of the tip growth process, with a particular focus on the subcellular targeting of newly synthesized cell wall components, and their roles in this form of plant cell expansion.展开更多
文摘A cell suspension culture of Panax ginseng which may be continuously subcultured has been established. Embryogenic callus derived from clutured young leaves was used to initiate the culture.Plant growth regulators, basal medium formula and carbohydrate levels were examined to determine their various effects on suspension culture cell growth and development. The best selection of plant growth regulator, hasal medium and carbohydrate level is 2 mg / L 2,4-D: 0.5 mg / L KT,MS and 3% sucrose respectively.
基金the National Natural Science Foundation of China! (No . 39770 0 81 )
文摘Boron is an essential nutrition for higher plants. However, the primary function of boron remains a matter of discussion. Boron may function by forming complexes with compounds having cis \|hydroxyl groups(diols), e.g., pectic materials in cell walls, glycoproteins or glycolipids in membranes and o \|diphenols. The well\|defined functions of boron are its involvement in maintaining cell wall structure and both the structural and the functional integrity of plasma membrane. Lack of boron causes an increase in the leakage of ions and compounds which reflects the impairment of plasma membrane. Boron is functionally important in forming a pectic network in cell wall which is responsible for the extensibility of cell wall and consequently regulates cell growth.
文摘Azospirillum brasilense is a well known plant growth-promoting rhizobacterium. Plant cell growth is constrained by the primary cell wall (CW) which contains polysaccharide-bound hydroxycinammic acids (HCAs). They derive from phenylpropanoid metabolism, which first step is the reaction catalyzed by phenylalanine ammonia-lyase (PAL;EC 4.3.1.24). Also CW peroxidases (FAPOD;EC 1.11.1.7) play a key role in the stiffening of the CW, and in the cessation of cell elongation. Knowledge of the biochemical effects the bacteria could elicit into plant CW and how these responses could change the hypocotyl physiology still remains scarce. The objective of this work was to unravel the effects of A. brasilense Sp245 inoculation on HCAs of the primary CW in apical and basal segments of cucumber seedlings hypocotyls. Azospirillum inoculation increased hypocotyls’ length. Transferulate and p-coumarate were the major HCAs. Dimmers were detected only in the basal region of 13- and 15-d-old hypocotyls. The ratio t-ferulate/dimmer (an inverse index of CW cross-linking) was five times higher in inoculated seedlings. Enzyme activities determined were not directly involved in HCAs content changes. It was previously reported that the CW was a target for A. brasilense growth promotion. This work corroborates that the phenolics, FA, DFA, and p-coumarate bound to the CW are also involved in Azospirillum plant growth promoting strategies.
基金funded by the Division of Chemical Sciences, Geosciences, and Biosciences, Offce of Basic Energy Sciences of the U.S. Department of Energy through Grant DE‐FG02‐07ER15887funds from the National Science Foundation grant 0937323 provided salary support for F.G
文摘Root hairs and pollen tubes are formed through tip growth, a process requiring synthesis of new cell wall material and the precise targeting and integration of these components to a selected apical plasma membrane domain in the growing tips of these cells. Presence of a tip-focused calcium gradient, control of actin cytoskeleton dynamics, and formation and targeting of secretory vesicles are essential to tip growth. Similar to cells undergoing diffuse growth, cellulose, hemi-celluloses, and pectins are also deposited in the growing apices of tip-growing cells. However, differences in the manner in which these cell wall components are targeted and inserted in the expanding portion of tip-growing cells is reflected by the identification of elements of the plant cell wall synthesis machinery which have been shown to play unique roles in tip-growing cells. In this review, we summarize our current understanding of the tip growth process, with a particular focus on the subcellular targeting of newly synthesized cell wall components, and their roles in this form of plant cell expansion.
