Epicotyl Research Articles

DEFENSIVE MECHANISMS OF A RHIZOBIA - INFECTED LEGUME

The data on the defensive mechanisms of a legume plant infected with nodule bacteria (rhizobia) have been summarized. The participation of plant defensive systems MTI (MAMP-triggered immunity) and ETI (effector-triggered immunity) in counteracting rhizobia invasion as probable pathogens into root tissues at the initial stages of organisms interaction, and later on as a regulating mechanism of root rhizobial infection is asserted. The plant ability to block rhizobia invasion into plant’s other organs (for instance, pea epicotyls) is stated. A notion of legume local and systemic resistance to rhizobial infection is proposed. In the first case rhizobia suppress immune response of plant root cells; in the second – enhance plant resistance to rhizobia. The role of Nod-factors of rhizobia (NFs) and interacting plant receptors in blocking root defensive reactions and triggering signal cascade within nodule organogenesis is considered. It is concluded that innate legume cell immunity actively participates in formation and functioning of legume-rhizobial symbiosis.

Morphological expressions in seedlings of Oroxylum indicum (L.) Vent. – a well known medicinal tree of tropics and subtropics

The main aim of the present study was to record morphological expressions and taxonomic significance in seedlings of Oroxylum indicum. Seedlings have been observed up to 5th leaf stage for 84 days from morpho-taxonomic view point. Seedling germination was Macaranga type. The morphological attributes found taxonomically significant are collet (with distinct ring), paracotyledon blade (anisocotylar, reniform, bilobed and deeply emarginated), glabrous hypocotyl and epicotyl and leaves simple up to 4th leaf stage, but compound afterwards.

Effect of LED Light Radiation on Antioxidant Activity and Agrobacterium-mediate Transformation of Azuki Bean Epicotyls

Influence of LED (light-emitting diode) light on antioxidant activity of etiolated azuki bean seedlings was studied. Free radical scavenging activity was measured with the standard DPPH (1, 1-diphenyl-2-picryl hydrazyl) method. Red (625-630 nm) light radiated seedlings expressed significantly higher scavenging activity than other treatments, such as blue (465-470 nm) and white light. In order to testing the possible influence of LED radiation to azuki bean epicotyls on Agrobacterium-mediated gene transfer efficiency, LED light (red, blue, or white) was applied simultaneously to plant segments with Agrobacterium tumefaciens strain EHA105 in which contains the binary plasmid pCAMBIA1201. Evidences of Agrobacterium- induced necrosis in target plant tissues and its link to reactive oxygen species (ROS) were investigated. The degrees of hypersensitive necrotic reaction in plant cells were affected by LED treatments. Irradiation with blue light resulted in increasing GUS gene expression in azuki bean explants and the increase in gene expression is possibly correlated with moderates DPPH-radical scavenging activity and low H2O2 accumulation in blue light-treated plant segments. Our data revealed that blue or red LED light treatment promotes Agrobacterium infection and blue light treatment improves transformation efficiency with higher cell viability. A possible application of our findings to the Agrobacterium-mediated azuki bean transformation was presented in the discussion.

Adventitious plantlet regeneration from different explants of Aegle marmelos (L.) Corr.

Plant regeneration was achieved from the diverse explants such as epicotyl, cotyledon, hypocotyl and root explants of important medicinal plant Aegle marmelos. Explants were obtained from 4 week old axenic seedlings of A. marmelos and cultured on Murashige and Skoog (MS) medium supplemented with plant growth regulators to ascertain the suitable explants and media composition for mass production. Cytokinins benzylaminopurine (BAP) and kinetin (Kin) were used for multiple shoot induction. Between two cytokinin tested, BAP was more efficient than Kin with respect to the initiation and subsequent proliferation of shoot buds. Addition of an auxin along with cytokinin improved the shoot production capacity. Shoot buds could be initiated from all the explants tested, with epicotyl explants producing the highest average number of shoots/explant. MS medium supplemented with 2.2 μM BAP + 1.425 μM indole-3-acetic acid (IAA) produced maximum number of shoots. The regenerated shoots were further multiplied by sub culturing on fresh medium. The elongated shoots were shifted to half-strength MS medium supplemented with different concentrations of IAA, α-naphthaleneacetic acid (NAA) and indole-3-butyric acid (IBA) for root induction. Rooting was better in the medium augmented with 2.85 μM IAA. About 90% of the rooted plantlets survived acclimatization and transfer to the field. Key words: Aegle marmelos, medicinal plant, micropropagation, seedling explants, cytokinin

Experimental Researches Regarding in vitro Multiplication Innovation by Direct Organogenesis in Brussels Cabbage (Brassica oleracea L. convar. oleracea, var. gemmifera)

Modern biotechnologies offer the possibility to multiplication the biologic vegetal structures by shaping the morphological phenomena (organogenesis or embryogenesis), which ensure both the maintenance of their characteristic elements as well as their multiplication in a number of units as extended as possible, starting with a certain type of explant and its intrinsic capacity, according to which, under the influence of in vitro culture, certain cells pertaining to it manifest properties specific to stem vegetal cells. In consequence, the aim of the experimental researches presented in this study was the innovation of in vitro multiplication at Brussels cabbage ( Brassica oleracea L. convar. oleracea var. gemmifera ), from subvarieties Rosella and Sanda , by direct caulogenesis induced under the influence of explant type (leaf, cotyledon, epicotyl, hypocotyl and radicle) and through direct rhizogenesis induced under the influence of exogenous auxin type (NAA or IBA). The best caulogenesis response in case of each of the two subvarieties of Brussels cabbage ( Brassica oleracea L. convar. oleracea var. gemmifera ) was recorded by experimental variant that consisted of using the explants of cotyledon type. While the best direct rhizogenesis response at Rosella subvariety of Brussels cabbage ( Brassica oleracea L. convar. oleracea var. gemmifera ) was recorded on experimental variant that consisted of using NAA exogenous auxin 0.25 mg/l, and in case of Sanda subvariety of Brussels cabbage ( Brassica oleracea L. convar. oleracea var. gemmifera ) the best direct rhizogenesis response was recorded on experimental variant that consisted of using IBA exogenous auxin 0.75 mg/l.

In vitro plant regeneration from epicotyl explant of Withania somnifera (L.) Dunal

Studies were carried out to investigate the regeneration and rapid multiplication of Withania somnifera (L.) in vitro. Direct and indirect regeneration protocols for multiple shoots development from epicotyl explants of 50 to 60 days old seedlings were established. The shoots were initiated directly from epicotyl explant on 6-benzyl amino purine (BAP: 2.0 mg/L) along with indole-3-acetic acid (IAA: 0.2 mg/L), and the maximum of 15.5 ± 0.90 shoots/explant were achieved by subsequent subcultures at 4 weeks interval in the same medium. Calli (98.3%) were produced from epicotyl explant on 2,4-dichlorophenoxy acetic acid (2,4-D: 2.0 mg/L) along with kinetin (Kn: 0.6 mg/L), and shoots were initiated from calli on BAP (1.0 mg/L) along with adenine sulphate (AdS: 20.0 mg/L). Proliferation of shoots was achieved by subsequent subcultures at 4 weeks interval in the same medium. The maximum value of 25.3 ± 1.81 shoots/explant was achieved in the second subculture of indirect regeneration. Murashige and Skoog (MS) medium along with gibberellic acid (GA3) at 1.0 mg/L produced maximum 73.3 and 95.5% of shoot elongation in direct and indirect regenerated shoots, respectively. On the other hand, MS medium with indole-3-butyric acid (IBA) at 0.8 mg/L induced maximum 86.7% and 90.0% of rooting from elongated shoots of direct and indirect regeneration, respectively. The rooted plants were transferred to small cups filled with sterilized mixture containing soil, sand and vermiculite (1:2:1, v/v/v) for hardening. About 90% of plants survived in the hardening process, and then the plants were established successfully in the experimental field. This protocol yielded a higher number of shoots within a short period. Consequently, the protocol developed in this study offers a simple and improved in vitro method to regenerate W. somnifera. Key words: Withania somnifera, epicotyls, tissue culture, shoot elongation, root induction.

Effect of Parkia Biglobosa (JACQ) G. Don. Pod Extracts on its Seed Germination and Seedling Development.

The pod extracts at different concentrations influenced the seed germination and seedling vegetative growth of twenty-six different Parkiabiglobosa(JACQ) G. Don Samples. Aqueous Parkia pod extracts of various concentrations (5, 10, 15 and 20g in 100ml of water) were used for the planting of the Parkia seeds and water as control. Significant (at p=0.05) reduction was observed in concentration of 20g of Parkia pod. The seed germination, epicotyl and hypocotyl lengths of the seedlings of the different Parkia trees exhibited varying responses to the extracts at various concentrations among the twenty-six Parkia biglobosa tree seeds used for the germination study within the three weeks of the experiment. The retardation in the seedlings vegetative growth was suspected to influence by the allelopathic components in the pod extracts. The varied responses of the Parkia seedlings to these extract concentrations were assumed to be either from the pod used which were selected from all the tree samples or that the seedlings were sensitive to an allelophatic chemicals of their own pod extracts or to other pods extracts.

Experimental research on in vitro propagation through direct somatic embryogenesis of basil (Ocimum basilicum L.).

Induction, generation and development of embryogenic somatic phenomena are matters that can be modeled by monitoring the interplay between exogenous phytohormones and explants. As a result, this work presents experimental studies that illustrate the influence that exogenous cytokinins (BAP and TDZ), and auxins (NAA or IBA) have, added in the composition of the artificial nutritive medium, for modeling the in vitro propagation through direct somatic embryogenesis in two cultivars of basil (Ocimum basilicum L. var. Marseille and Ocimum basilicum L. var. Red Rubin), starting from different types of explants (leaf, cotyledon, epicotyl, hipocotyl and radicle). The best embryogenic response was recorded for experimental variant consisting in TDZ cytokinin and IBA auxin in quantities of 1 mg/l respectively 0,5 mg/l, and cotyledon type explant.

Preliminary Investigation of Experimental Research on Savory (Satureja hortensis L.) In Vitro Modeling Possibility Using the Calogenesis Technique

Investigating the possibilities for in vitro plant modeling by using the calogenesis technique is one of the ways to exploit cell plasticity – the vegetable type, which plant biotechnology now offers an alternative for obtaining biomass as a source of raw material in various industries. One of the known plants cultivated by humans since ancient time, and recognized in the contemporary period as a dedicated source of plant material for different industries, because it has properties that recommend its use in food, medicine and beekeeping, is savory (Satureja hortensis L.). Our preliminary experimental research aimed at investigating the possibility of in vitro modeling of savory (Satureja hortensis L.) by using the calogenesis technique. This paper presents the experimental results which have been achieved by investigating the possibility of practical achievement, both by establishing aseptic cultures using savory (Satureja hortensis L.) seeds, and also by in vitro modeling of savory (Satureja hortensis L.) explants, considering the leaf, cotyledon, epicotyl, hypocotyl and radicle, in under to obtain callus by the influence of exogenous phytohormones (BA, TDZ and 2,4-D).

GRAFTING IN SEEDS, RADICLES, HYPOCOTYLS AND EPICOTYLS OF CHESTNUT

GRAFTING IN SEEDS, RADICLES, HYPOCOTYLS AND EPICOTYLS OF CHESTNUT

In vitro Shoot Development from Three Different Nodes of Cotton (Gossypium hirsutum L.)

In plant tissue culture studies, obtaining new plantlets from many different parts of a plant is a very important feature with direct or indirect ways and all nodes are considerable sources, although they show different regeneration capacities from one species to another. In this research, in vitro direct shoot developments from different nodes of cotton (Gossypium hirsutum L. var. Nazilli 84S) were comparatively studied. Cotyledonary nodes, first and second leaf nodes together with hypocotyl, shoot and epicotyl pieces from 35-day-old in vitro grown plants were cultured on MS media supplemented with 0.1 mg/l KIN (kinetin). Cultured seeds and explants were kept at growth chamber with a photoperiod for 16 hours light (7500 lx) and 8 hours dark, at 25 oC and 70 % humidity. A rapid in vitro shoot development was obtained from all three types of explants and no significant differences among young plants were observed. Shoot development was maximum 74.2 % in cotyledonary nodes, followed by 60.7 % and 41.6 %, respectively for first and second leaf nodes. All these shoots were capable of rooting in Woody Plant Medium (WPM), supplemented with 1 mg/l IBA (indole-3-butyric acid), and establishing in soil after 15-30 days.

Potentiation of Phytoalexin Accumulation in Elicitor-treated Epicotyls of Pea (Pisum sativum) by a Diacylglycerol Kinase Inhibitor

When epicotyl tissues of pea were treated with a diacylglycerol (DAG) kinase inhibitor (R59022), enhanced induction of the phytoalexin accumulation occurred which was induced by fungal elicitor. The marked induction was associated with a sustained accumulation of phenylalanine ammonia-lyase (PAL)-mRNA and the consequent increase in PAL activity. These results suggest that inhibition of DAG breakdown leads to increased induction of phytoalexin accumulation and support the hypothesis that DAG kinase negatively regulates the signal transduction. Zusammenfassung Nach einer Behandlung des Epikotylgewebes von Erbsen mit einem Hemmstoff der Diacylglycerol (DAG)-Kinase (R59022) wurde eine Verstarkung der Phytoalexinakkumulation beobachtet, die durch einen pilzlichen Elicitor induziert worden war. Die ausgepragte Induktion wurde mit einer anhaltenden Akkumulation der Phenylalanin-Ammonlyase (PAL)-mRNS und mit anschliesender erhohter PAL-Aktivitat assoziiert. Diese Ergebnisse deuten darauf hin, dass eine Hemmung des DAG-Abbaus zu einer erhohten Induktion der Phytoalexinakkumulation fuhrt und auserdem unterstutzen sie die Hypothese, dass die Signaltransduktion durch die DAG-Kinase negativ reguliert wird.

Synergistic Effect of Sterol Glucoside on Brassinolide Activity in Lamina Inclination and Epicotyl Elongation

ブラシノライドによるイネ葉身屈曲およびマングビーン上胚軸伸長の促進活性を指標にして, ステロール (スチグマステロール,β-シトステロール, カンペステロール) グルコース配糖体の相乗作用を調べた.β-シトステロール配糖体とカンペステロール配糖体は3対2の混合物のままで調べられた. ステロール配糖体は単独ではまったく生物活性を示さないが, ブラシノライドと混用すると, ブラシノライド単独よりもイネ葉身屈曲試験において約6倍, マングビーン上胚軸伸長試験において約10倍活性が増強されることが明らかとなった. ブラシノライドに相乗作用を示すのはスチグマステロール配糖体に限られ, カンペステロール/β-シトステロール配糖体には観察されなかった.

Partial Characterization of the Protease(s) Involved in the Degradation of Phytochrome Polypeptide in Etiolated Epicotyl Tissue of <italic>Pisum sativum</italic>

Afin de caracteriser le systeme de degradation du phytochrome, l'effet de chelateurs et d'inhibiteurs de proteases est examine dans des segments d'epicotyle de semis etioles de pois

The Effect of Calcium Antagonists on Auxin-induced Elongation and on the Expression of Two Auxin-Regulated Genes in Pea Epicotyls

On examine les effets de chelateurs du calcium, d'agents bloquant les canaux ioniques calciques et du ionophore A23187 sur l'elongation induite par l'auxine ainsi que l'induction des ARN messagers

Wounding of Aged Pea Epicotyls Enhances the Reinitiating Ability of Isolated Ribosomes

Mise au point d'un systeme in vitro de synthese proteique afin d'identifier quels aspects du processus de transcription sont modifies par blessure

Shoot Auxin and Light in the Mechanism Maintaining the Posture of the Cotyledons ofLinum usitatissimum

The mean cotyledon angle (liminal day posture) of flax is linearly related to light intensity, the cotyledons being raised with increasing intensity ; adjustments occur when plants are transferred to new conditions. Short days, low light intensity, and prolonged darkness result in epinasty. Epinastic and hyponastic responses are enhanced by excision of the epi cotyl shoot. Application of indoleacetic acid to the cut shoot is an effective substitute for the excised portion. Ringing the intact epicotyl with 2,3,5-tri-iodobenzoic acid has an effect comparable to excision. Given continuously or in a light/dark cycle, blue light induces hyponasty, and red light maintains the liminal posture for about 48 h after which time epinasty occurs. Far-red light given continuously induces epinasty to an extent comparable to the effect of darkness. Irradiation with far-red light even for brief periods prior to placing the plants in darkness enhances the epinastic response : the effect of far-red light is reversed by a subsequent short exposure to red light. Interruption of a prolonged period of darkness by blue light considerably lessens the subsequent epinastic reaction whether or not any epinasty has occurred before the light break. Red or white light given under these circumstances has less effect.