oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Adventitious Roots and Secondary Metabolism
Hosakatte Niranjana Murthy,Eun Joo Hahn,Kee Yoeup Paek,
Hosakatte Niranjana Murthy
,Eun Joo Hahn,Kee Yoeup Paek

生物工程学报 , 2008,
Abstract: Plants are a rich source of valuable secondary metabolites and in the recent years plant cell, tissue and organ cultures have been developed as an important alternative sources for the production of these compounds. Adventitious roots have been successfully induced in many plant species and cultured for the production of high value secondary metabolites of pharmaceutical, nutraceutical and industrial importance. Adoption of elicitation methods have shown improved synthesis of secondary metabolites in adventitious root cultures. Development of large-scale culture methods using bioreactors has opened up feasibilities of production of secondary metabolites at the industrial levels. In the present review we summarize the progress made in recent past in the area of adventitious root cultures for the production of secondary metabolites.
Auxin Control in the Formation of Adventitious Roots  [cached]
Tiberia I. POP,Doru PAMFIL,Catherine BELLINI
Notulae Botanicae Horti Agrobotanici Cluj-Napoca , 2011,
Abstract: Adventitious rooting is a complex process and a key step in the vegetative propagation of economically important woody, horticultural and agricultural species, playing an important role in the successful production of elite clones. The formation of adventitious roots is a quantitative genetic trait regulated by both environmental and endogenous factors. Among phytohormones, auxin plays an essential role in regulating roots development and it has been shown to be intimately involved in the process of adventitious rooting. Great progress has been made in elucidating the auxin-induced genes and auxin signaling pathway, especially in auxin response Aux/IAA and Auxin Response Factor gene families. Although some important aspects of adventitious and lateral rooting signaling have been revealed, the intricate signaling network remains poorly understood. This review summarizes some of the current knowledge on the physiological aspects of adventitious root formation and highlights the recent progress made in the identification of putative molecular players involved in the control of adventitious rooting. Despite much has been discovered regarding the effects and regulation of auxins on plant growth since the Darwin experiments, there is much that remains unknown.
Role of adventitious roots in water relations of tamarack (Larix laricina) seedlings exposed to flooding
Mónica Calvo-Polanco, Jorge Se?orans, Janusz J Zwiazek
BMC Plant Biology , 2012, DOI: 10.1186/1471-2229-12-99
Abstract: Seedlings were subjected to the flooding treatment for six months, which resulted in an almost complete disintegration of the existing root system and its replacement with adventitious roots. We compared gas exchange parameters and water relations of flooded plants with the plants growing in well-drained soil and examined the root structures and root water transport properties. Although flooded seedlings had lower needle chlorophyll concentrations, their stomatal conductance, net photosynthesis rates and shoot water potentials were similar to non-flooded plants, indicative of flooding tolerance. Flooded adventitious roots had higher activation energy and a higher ratio of apoplastic to cell-to-cell water flow compared with non-flooded control roots as determined with the 1-hydroxypirene 3,6,8-trisulfonic acid apoplastic tracer dye. The adventitious roots in flooded plants also exhibited retarded xylem and endodermal development and accumulated numerous starch grains in the cortex. Microscopic examination of root sections treated with the PIP1 and PIP2 antibodies revealed high immunoreactivity in the cortex of non-flooded roots, as compared with flooded roots.Structural modifications of adventitious roots suggest increased contribution of apoplastic bypass to water flow. The reduced dependence of roots on the hypoxia-sensitive aquaporin-mediated water transport is likely among the main mechanisms allowing tamarack seedlings to maintain water balance and gas exchange under flooding conditions.Flooding creates hypoxic conditions around the roots affecting a number of physiological processes in plants including gas exchange, carbohydrate metabolism and water relations [1-3]. Some woody plants that are adapted to flooding conditions develop hypertrophic lenticels and/or root aerenchyma to increase aeration [4,5]. In other species, including tamarack (Larix laricina (Du Roi) K. Koch), flooding triggers the development of adventitious roots, which help the trees tolerate s
Meristematic endodermis and secretory structures in adventitious roots of Richterago Kuntze (Mutisieae-Asteraceae)
Melo-de-Pinna, Gladys F.A.;Menezes, Nanuza L.;
Brazilian Journal of Botany , 2003, DOI: 10.1590/S0100-84042003000100002
Abstract: the meristematic endodermis in adventitious roots of richterago species originates in one of the fundamental meristem cells, which undergo sucessive anticlinal and periclinal divisions to build the inner cortex. the meristematic endodermis or proendodermis remains as a meristematic layer until its differentiation into endodermis, with casparian strip. when sieve elements differentiate, endodermic secretory canals of esquizogenous origin are present at the region adjacent to primary phloem. articulated laticifers, with cells perforated at both terminal and transversal walls, also occur during initial phases of secondary development. presence of inulin as reserve carbohydrate in the inner cortex and vascular tissue may be related to abiotic factors, as an adaptive strategy of these species.
Meristematic endodermis and secretory structures in adventitious roots of Richterago Kuntze (Mutisieae-Asteraceae)
Melo-de-Pinna Gladys F.A.,Menezes Nanuza L.
Brazilian Journal of Botany , 2003,
Abstract: The meristematic endodermis in adventitious roots of Richterago species originates in one of the fundamental meristem cells, which undergo sucessive anticlinal and periclinal divisions to build the inner cortex. The meristematic endodermis or proendodermis remains as a meristematic layer until its differentiation into endodermis, with Casparian strip. When sieve elements differentiate, endodermic secretory canals of esquizogenous origin are present at the region adjacent to primary phloem. Articulated laticifers, with cells perforated at both terminal and transversal walls, also occur during initial phases of secondary development. Presence of inulin as reserve carbohydrate in the inner cortex and vascular tissue may be related to abiotic factors, as an adaptive strategy of these species.
Enhancement of Anti-Inflammatory Activity of Aloe vera Adventitious Root Extracts through the Alteration of Primary and Secondary Metabolites via Salicylic Acid Elicitation  [PDF]
Yun Sun Lee, Hyun Kyoung Ju, Yeon Jeong Kim, Tae-Gyu Lim, Md Romij Uddin, Yeon Bok Kim, Jin Hong Baek, Sung Won Kwon, Ki Won Lee, Hak Soo Seo, Sang Un Park, Tae-Jin Yang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0082479
Abstract: Aloe vera (Asphodeloideae) is a medicinal plant in which useful secondary metabolites are plentiful. Among the representative secondary metabolites of Aloe vera are the anthraquinones including aloe emodin and chrysophanol, which are tricyclic aromatic quinones synthesized via a plant-specific type III polyketide biosynthesis pathway. However, it is not yet clear which cellular responses can induce the pathway, leading to production of tricyclic aromatic quinones. In this study, we examined the effect of endogenous elicitors on the type III polyketide biosynthesis pathway and identified the metabolic changes induced in elicitor-treated Aloe vera adventitious roots. Salicylic acid, methyl jasmonate, and ethephon were used to treat Aloe vera adventitious roots cultured on MS liquid media with 0.3 mg/L IBA for 35 days. Aloe emodin and chrysophanol were remarkably increased by the SA treatment, more than 10–11 and 5–13 fold as compared with untreated control, respectively. Ultra-performance liquid chromatography-electrospray ionization mass spectrometry analysis identified a total of 37 SA-induced compounds, including aloe emodin and chrysophanol, and 3 of the compounds were tentatively identified as tricyclic aromatic quinones. Transcript accumulation analysis of polyketide synthase genes and gas chromatography mass spectrometry showed that these secondary metabolic changes resulted from increased expression of octaketide synthase genes and decreases in malonyl-CoA, which is the precursor for the tricyclic aromatic quinone biosynthesis pathway. In addition, anti-inflammatory activity was enhanced in extracts of SA-treated adventitious roots. Our results suggest that SA has an important role in activation of the plant specific-type III polyketide biosynthetic pathway, and therefore that the efficacy of Aloe vera as medicinal agent can be improved through SA treatment.
Comprehensive Transcriptome Analysis Unravels the Existence of Crucial Genes Regulating Primary Metabolism during Adventitious Root Formation in Petunia hybrida  [PDF]
Amirhossein Ahkami, Uwe Scholz, Burkhard Steuernagel, Marc Strickert, Klaus-Thomas Haensch, Uwe Druege, Didier Reinhardt, Eva Nouri, Nicolaus von Wirén, Philipp Franken, Mohammad-Reza Hajirezaei
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0100997
Abstract: To identify specific genes determining the initiation and formation of adventitious roots (AR), a microarray-based transcriptome analysis in the stem base of the cuttings of Petunia hybrida (line W115) was conducted. A microarray carrying 24,816 unique, non-redundant annotated sequences was hybridized to probes derived from different stages of AR formation. After exclusion of wound-responsive and root-regulated genes, 1,354 of them were identified which were significantly and specifically induced during various phases of AR formation. Based on a recent physiological model distinguishing three metabolic phases in AR formation, the present paper focuses on the response of genes related to particular metabolic pathways. Key genes involved in primary carbohydrate metabolism such as those mediating apoplastic sucrose unloading were induced at the early sink establishment phase of AR formation. Transcriptome changes also pointed to a possible role of trehalose metabolism and SnRK1 (sucrose non-fermenting 1- related protein kinase) in sugar sensing during this early step of AR formation. Symplastic sucrose unloading and nucleotide biosynthesis were the major processes induced during the later recovery and maintenance phases. Moreover, transcripts involved in peroxisomal beta-oxidation were up-regulated during different phases of AR formation. In addition to metabolic pathways, the analysis revealed the activation of cell division at the two later phases and in particular the induction of G1-specific genes in the maintenance phase. Furthermore, results point towards a specific demand for certain mineral nutrients starting in the recovery phase.
Liquid Culture of Adventitious Roots is a Potential Alternative to Field Cultivation for Psammosilene tunicoides, a Rare and Endangered Endemic Medicinal Plant
Zongshen Zhang,Zhenyan Yu,Zhaoxia Jin,Jun Liu
Advance Journal of Food Science and Technology , 2013,
Abstract: The aim of this study was to establish an adventitious roots culture system for sterile plantlet segments of P. tunicoides and improved the accumulation of total saponins in cultured roots. Psammosilene tunicoides is a native Chinese plant with high commercial value as medicinal herb. Combination of NAA and IBA significantly affected the adventitious roots formation on agar-solided B5 media and a maximal induction rate of 83% was obtained at 24±2°C with a photoperiod of 12 h. With a shaking of 110 rpm in darkness, transferring the detached adventitious roots to the growth regulator free 1/2 B5 liquid media notably increased the biomass production compared to that on solid media over a 30-day-culture period. Further analyses showed that more saponins could be accumulated in the liquid culture than in the solid culture and the addition of exogenous oxalic acid to the liquid media could enhance the accumulation of total saponins in adventitious roots. These results suggested that adventitious roots culture will be an efficient alternative to the field cultivation of intact plants for the production of useful natural compounds from P. tunicoides.
Effects of Flooding on Growth, Yield and Aerenchyma Development in Adventitious Roots in Four Cultivars of Kenaf (Hibiscus cannabinus L.)  [PDF]
A. Polthanee,T. Changdee,J. Abe,S. Morita
Asian Journal of Plant Sciences , 2008,
Abstract: A pot experiment was performed to examine the effects of flooding on growth, yield and aerenchyma development in adventitious roots of four kenaf (Hibiscus cannabinus L.) cultivars. Three flooding treatments consisting of early season flooding (30 days after planting), mid-season flooding (60 days after planting) and late season flooding (90 days after planting), as well as non-flooding control were used in the present study. The results show that soil flooding significantly increased plant height by 108 and 107% over control in early flooding and mid-flooding, respectively. Early flooding significant decreased the number of leaves and leaf area of whole plant and core dry weights by 15, 19 and 20% over non-flooding control, respectively. Soil flooding did not show any significant effect on plant height and number of leaf among cultivars, but did for leaf area, leaf dry weight and core dry weight. Early season and mid-season flooding significant decreased root dry weight in soil by 71 and 49% over non-flooded control, respectively. No adventitious roots developed in non-flooded control. Adventitious roots located in water above soil surface had dry weight of 18, 11 and 6 g plant-1 in early season, mid season and late season flooding, respectively. No significant difference in root dry weight located in soil and root dry weight located in water above soil surface were observed among cultivars. Aerenchyma formed in adventitious roots when the plant was subjected to flooding and was more developed in roots located in water above the soil surface as compared to roots located in soil. All the cultivars formed aerenchyma in their adventitious roots with variation among cultivars. Soil flooding significantly decreased fiber yield by 13% in non-flooded control in early season flooding treatments. However, mid-season and late season flooding did not show any significant difference on fiber yield in comparison with control. The cultivars was not significantly difference on fiber yield in the present experiment.
EFFECTS OF RESORCINOL AND SALICYLIC ACID ON THE FORMATION OF ADVENTITIOUS ROOTS IN HYPOCOTYL CUTTINGS OF VIGNA RADIATA
间苯二酚、水杨酸对绿豆下胚轴不定根形成的作用

Li Ling,
李玲

热带亚热带植物学报 , 1995,
Abstract: Twenty to 100mg L-1 resorcinol(Res)stimulated the formation of adventitious roots in hypocotyl cuttings of mung beau.Mixtures of the resorcinol with 20mg L-1IBA showed more effective than IBA or Res alone in promoting adventitious root formation.The essential role of Res in promoting adventitious rootS was in relation to the increasing activities of IAA oxidase and polyphenol oxidase in the early stages of root regeneration.ten to 100 mg L-1 salicylic acid(SA)inhibited adventitious root formation and decrea...
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.