@article { ISI:000256086600009, title = {Effect of TDZ and 2, 4-D on peanut somatic embryogenesis and in vitro bud development}, journal = {Plant Cell Tissue and Organ Culture}, volume = {94}, number = {1}, year = {2008}, month = {JUL}, pages = {85-90}, publisher = {SPRINGER}, type = {Article}, address = {VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS}, abstract = {

Failure of peanut somatic embryos to convert into plantlets is attributed to the abnormal development of the plumule. Thidiazuron (TDZ) was effective in the conversion of peanut somatic embryos to plantlets by triggering morphogenetic activity in the abnormal plumules of the rooted somatic embryos. The present study aimed to induce normal embryo differentiation by culturing the embryogenic masses in embryo development medium containing 2,4-D and various concentrations of TDZ. Although this was not achieved due to restricted somatic embryo development in the presence of TDZ, bud-like projections appeared in the embryogenic masses when these were cultured in media containing combinations of 2,4-D and TDZ. These projections developed into buds, which subsequently formed shoots and plantlets. The response varied with the concentration and exposure of TDZ. At lower concentrations, the buds appeared in a defined row in the equatorial region of the explant, and with extended incubation, more and more buds appeared in rows alongside the initial row. Induction of multiple buds in a defined row in this specific site (equatorial region) suggested the presence of potent cells around this region. At higher concentrations, these projections appeared in large numbers spread over the whole upper part of the embryogenic mass starting from the equatorial region. The ability of embryogenic mass to convert into organogenic mass and to produce large number of organogenic buds provides an excellent system for basic studies and for the genetic transformation of peanut.

}, keywords = {Arachis hypogaea, embyogenic mass, somatic embryogenesis, thidiazuron}, issn = {0167-6857}, doi = {10.1007/s11240-008-9390-0}, author = {Joshi, Madhumita and Sujatha, K. and Hazra, Sulekha} } @article { ISI:000257200200028, title = {Imaging the stomatal physiology of somatic embryo-derived peanut leaves by scanning electrochemical microscopy}, journal = {Analytical and Bioanalytical Chemistry}, volume = {391}, number = {6}, year = {2008}, month = {JUL}, pages = {2227-2233}, publisher = {SPRINGER HEIDELBERG}, type = {Article}, address = {TIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANY}, abstract = {

The stomatal physiology, chlorophyll distribution and photosynthetic activity of somatic embryo (SE)- and seedling-derived peanut plants grown in vitro (test tube-grown) and extra vitrum (soil-grown) are investigated using scanning electrochemical microscopy (SECM). This SECM imaging is performed in two different feedback modes, corresponding to oxygen evolution and chlorophyll distribution. More specifically, the oxygen evolution profiles of the in vitro leaves indicate important differences in leaf anatomy between the SE- and seedling-derived leaves. On the other hand, the chlorophyll distribution images show individual stomata of size ca. 27 +/- 5 mu m. Further studies on senescing (aged) leaves reveal interesting voltammograms that vary widely over the stomatal complexes and the surrounding tissues, probably due to the release of electroactive metabolites during chlorophyll breakdown when the leaves turn yellow. Thus, the present investigation could open up new opportunities for characterizing botanical systems using electroanalytical techniques. In addition, it could provide further insights into various areas of current relevance, including signal transduction, cell fate/differentiation and developmental biology.

}, keywords = {leaf senescence, oxygen evolution, photosynthesis, SECM, somatic embryogenesis, stomata}, issn = {1618-2642}, doi = {10.1007/s00216-008-2132-7}, author = {Parthasarathy, Meera and Singh, Shweta and Hazra, Sulekha and Pillai, Vijayamohanan K.} } @article { ISI:000270842400009, title = {Somatic embryogenesis from the axillary meristems of peanut (Arachis hypogaea L.)}, journal = {Plant Biotechnology Reports}, volume = {3}, number = {4}, year = {2009}, month = {OCT}, pages = {333-340}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Developmental anomalies in the plumule meristem of peanut (Arachis hypogaea L.) somatic embryos resulted in poor shoot differentiation and reduced plant recovery. Existing meristems with caulogenic potential have never been tested for embryogenesis in peanut. The present experiment was designed to test the mature zygotic embryo axis derived plumule with three meristems for somatic embryogenesis. Embryogenic masses and embryos developed from the caulogenic meristems in the axils. Exposure of 2 weeks in primary medium with 90.5 A mu M 2,4-D suppressed the shoot tip differentiation temporarily which then regained the ability to form the shoot on withdrawal of 2,4-D. Exposure of 4 weeks in primary medium with 90.5 A mu M 2,4-D suppressed the shoot tip differentiation irreversibly. No shoot formation was noted from the tips in any of the cultures which were in secondary medium with 13.6 A mu M 2,4-D. Development of somatic embryos directly from axillary meristems was confirmed histologically. Conversion frequency of these embryos was 11\%. Thus, in this report, we describe a method to obtain somatic embryos from the determined organogenic buds of the axillary meristem, by culturing the nodal explant vertically on embryo induction medium. It also displays the possibility of obtaining both embryogenic and organogenic potential in two parts of the same explant simultaneously. The possibility of extending this approach for genetic transformation in in vivo system through direct DNA delivery or Agrobacterium injection in meristems can also be explored. Using Agrobacterium rhizogenes, we have demonstrated the possibility of gene transfer in the axillary meristems of seed-derived plumule explant.

}, keywords = {Apical meristem, Axillary meristem, Mature zygotic embryo axis, Peanut, somatic embryogenesis}, issn = {1863-5466}, doi = {10.1007/s11816-009-0107-6}, author = {Singh, Shweta and Hazra, Sulekha} } @article { ISI:000303055200006, title = {In vitro morphogenic response in cotyledon explants of semecarpus anacardium L.}, journal = {Plant Biotechnology Reports}, volume = {6}, number = {2}, year = {2012}, month = {APR}, pages = {141-148}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

Three different morphogenic responses-caulogenesis, direct somatic embryogenesis, and callusing-were noted in cotyledon explants of Semecarpus anacardium L. cultured in woody plant medium (WPM) containing thidiazuron (TDZ). Thidiazuron, at all concentrations tested, induced organogenic as well as embryogenic responses. The organogenic buds differentiated to shoots and the embryogenic mass (EM) gave rise to globular embryos which differentiated up to cotyledon-stage embryos on repeated culture in growth regulator (GR)-free WPM medium containing 0.2\% activated charcoal after the removal of TDZ. The organogenic and embryogenic responses were optimal in 9.08 mu M TDZ after the removal of TDZ. Elongated shoots rooted in half-strength liquid WPM medium with 2.46 mu M indole butyric acid. Plants were successfully acclimatized and transferred to soil. Histological studies confirmed the direct origin of the organogenic buds from the cotyledon explants. The EMs produced somatic embryos on repeated culture in charcoal incorporated GR-free medium. Morphogenic callus formation from the cotyledon explants was also noted. This callus on repeated culture in WPM medium with charcoal differentiated into somatic embryos. Repetitive somatic embryogenesis was evident from direct and indirectly formed primary embryos. The somatic embryos did not convert into plantlets, though sporadic germination of embryos was observed through the emergence of roots.

}, keywords = {callus, Caulogenesis, Globular embryos, Growth regulator, Histology, somatic embryogenesis}, issn = {1863-5466}, doi = {10.1007/s11816-011-0207-y}, author = {Panda, Bhuban Mohan and Hazra, Sulekha} } @article { ISI:000322293300006, title = {Use of amino acids for a highly efficient somatic embryogenesis in grapevine {\textquoteleft}Crimson Seedless{\textquoteright}}, journal = {Vitis}, volume = {52}, number = {3}, year = {2013}, month = {JAN}, pages = {137-140}, publisher = {JKI-INSTITUT REBENZUCHTUNG}, address = {GEILWEILERHOF, D-76833 SIEBELDINGEN, GERMANY}, abstract = {

Somatic embryogenesis influenced by growth regulators and amino acids was studied in in vitro leaves of grapevine {\textquoteleft}Crimson Seedless{\textquoteright}. In vitro leaves of the cultivar were collected from multiple shoot cultures maintained on Murashige and Skoog{\textquoteright}s (MS) basal medium supplemented with 9 mu M N-6-benzyladenine (BA). Among the growth regulators used, BA at 4.5 mu M induced higher embryogenic response producing more number of somatic embryos per explant. This response was increased with the addition of 5 mu M naphthoxyl-acetic acid (NOA) to 1/2 MS containing 4.5 mu M BA. Further, supplementation of amino acids in the callus induction medium significantly improved the embryogenic response of in vitro leaves. The higher number of explants showing somatic embryo production (55.3 \%) and higher number of somatic embryos per explant (15.5 per explant) were recorded with the supplementation of 5 mM phenylalanine to callus induction medium. Primary somatic embryos showed repetitive embryogenesis on \% MS medium devoid of growth regulators. Plantlets derived from somatic embryos were transferred to soil-sand-peat mixture (1:1:1 v/v) and hardened plantlets were established in greenhouse with 90 \% survival. This somatic embryogenesis system has been successfully used for Agrobacterium-mediated transformation studies in {\textquoteleft}Crimson Seedless{\textquoteright} in our laboratory. To our knowledge, this is the first report on the use of amino acids for the high efficient somatic embryogenesis in grapevine.

}, keywords = {Amino acids, somatic embryogenesis, Vitis vinifera L., {\textquoteleft}Crimson Seedless{\textquoteright}}, issn = {0042-7500}, author = {Nookaraju, A. and Agrawal, Dinesh C.} } @article {46816, title = {Combinatorial approach through in vitro regeneration and phytochemical profiling of ceropegia media (huber) ans.: a potential way forward in the conservation of an endangered medicinal plant from the western ghats in India}, journal = {Journal of Plant Growth Regulation}, year = {2020}, month = {JUN }, type = {Article; Early Access 2020}, abstract = {

Ceropegia mediais an endemic and endangered plant as its propagation through seeds is unreliable due to low germination, slow growth and seedling decay under natural conditions. Also, tubers of this plant are edible serving as carbohydrate source with medicinal values leading to severe population decline in the natural habitat. To provide a sustainable solution, an efficient in vitro propagation protocol along with phytochemical profiling was developed forC. media. Callus cultures were induced from seedling and wild leaf tissues using the most effective Murashige and Skoog{\textquoteright}s (MS) medium with 2,4-dichlorophenoxyacetic acid (2,4-D; 2 mu M) and sucrose (3\%). Somatic embryos were acquired on MS medium with 1 mu M 6-Benzylaminopurine (BAP) and 1 mu M 2,4-D. Conversion into plantlets was attained only from tissue culture-derived seedling leaf (TCDSL) explant. Further, in vitro tuberization was achieved from TCDSL callus with BAP and Naphthalene acetic acid (NAA). AgNO(3)as an elicitor had a positive effect on both fresh and dry weights of callus. Successful acclimatization (58\%) was attained after two months resulting in normal phenotype in pots. Further, metabolite profiles of ten different tissues from wild and in vitro plants were compared. Total 82 compounds comprising alkaloids, fatty acids, fatty acid ester, steroids, terpenes and hydrocarbons were identified. Overall, results suggested enhanced production of selected metabolites with in vitro propagation and AgNO3, alleviating the problem of unavailability of planting materials. Thus, the current study might offer potential ways for the conservation of such RED enlisted species asC. media. [GRAHICS]

}, keywords = {Ceropegia media, GC-MS, Microtuberization, Secondary metabolites, Silver nitrate, somatic embryogenesis}, issn = {0721-7595}, doi = {10.1007/s00344-020-10173-6, Early Access Date = JUN 2020}, author = {Pandey, Meena and Dholakia, Bhushan B. and Jayaramaiah, Ramesha H. and Punekar, Sachin A. and Giri, Ashok P.} }