Annamalai Muthusamy

Influence of Helium‐Neon Laser Irradiation on Seed Germination In Vitro and Physico‐Biochemical Characters in Seedlings of Brinjal (Solanum melongena L.) var. Mattu Gulla

In the present study, the seeds of brinjal (Solanum melongena L.) var. Mattu Gulla were irradiated with single exposure of He–Ne laser at different doses of 5–40 J cm−2 and germinated aseptically. Thirty day old seedlings were harvested and the germination, growth, physiological and biochemical parameters were estimated and compared with un‐irradiated control seedlings. A significant enhancement in growth characters were noted with respect to length, fresh and dry weight of shoots and roots. In addition, chlorophyll (a and b), carotenoid content, anthocyanin and amylases (α and β) activities were found to be altered. Significant alterations in percentage of seed germination (P < 0.001) and time to 50% germination (P < 0.001) were observed in the irradiated seeds compared with the un‐irradiated controls. In conclusion, the results of the present study demonstrated that low dose (5–30 J cm−2) of He–Ne laser irradiation enhanced the germination process and altered growth, by positively influencing physiological and biochemical parameters of the brinjal seedlings compared with un‐irradiated control under in vitro conditions.

Responses of He-Ne laser irradiation on agronomical characters and chlorogenic acid content of brinjal (Solanum melongena L.) var. Mattu Gulla

Exposure to laser irradiation on seeds brings about the changes in agronomical characteristics of the plants. Solanum melongena L. var. Mattu Gulla, a variety of brinjal is of high economic value due to its unique colour and flavour. The aim of the study was to understand the influence of Helium-Neon (He-Ne) laser irradiation on agronomical characters of Solanum melongena L. var. Mattu Gulla in the field conditions. Various growth characteristics including seed germination percentage, survival rate, plant height, number of branches, and flowers and fruits were estimated during different developmental stages of the brinjal. In addition, the chlorogenic acid content of fruits obtained from the laser irradiated seeds were quantified using reversed-phase high-performance liquid chromatography (RP- HPLC). The plants from the seeds irradiated with different doses (20, 25 and 30J/cm2) of He-Ne laser showed significant enhancement on the growth characteristics when compared to the non-irradiated control groups. He-Ne laser irradiation also improved the yield characteristics of the plants significantly in in vivo conditions in comparison with control group. 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed using methanolic extract of matured fruit of Mattu Gulla on HepG2 and fibroblast cell lines. The IC50 values of fruit extract from laser irradiated groups were found to be similar to non-irradiated control groups. Chlorogenic acid content was found to be higher in 20J/cm2 and lower in 30J/cm2 treated fruit tissue. The current study thus elucidates the role of He-Ne laser as a biostimulator on brinjal var. Mattu Gulla not only in the in vitro conditions but also in the in vivo field conditions.

In vitro culture responses, callus growth and organogenetic potential of brinjal (Solanum melongena L.) to He-Ne laser irradiation

The present investigation was designed to analyze the influence of Helium-Neon (He-Ne 632.8nm) laser irradiation on defense enzymes, proline content and in vitro responses of callus induction, shoot initiation and on plantlet regeneration potential of brinjal. The seeds of Mattu Gulla (Solanum melongena L.) were irradiated with 20, 25 and 30J/cm2 of He-Ne laser followed by surface sterilization and sprouted on Murashige and Skoog medium without plant growth regulators. The activity of defense enzymes, proline content and the organogenetic potential of hypocotyl, leaf and shoot tip explants were determined from thirty day old seedlings. During seed germination, most of the seedlings showed normal two cotyledons whereas small number of seedlings showed tricotyledonous at 20J/cm2 treatment and no other morphological abnormalities were observed during further growth and development. There was no substantial variation was noted in both β-1,3-glucanase and chitinase activity as well as proline content which proves the He-Ne laser irradiation does not causes any stresses for the plant. The in vitro culture of hypocotyl, leaf and shoot tip explants from laser irradiated seedlings showed differential responses as compared to un-irradiated control. The laser induced enhancement of callus induction, growth rate of callus tissues and shoot tip, percentage of responses of shoot and root initiation, days to shoot and root initiation, shoots formed per callus, number of roots per shoots, length of roots and nuclear DNA content of in vitro raised plants were evaluated. Among the tested laser doses (20, 25 and 30J/cm2), 25J/cm2 showed significant biostimulatory effect over un-irradiated control seedlings. The present observations reveal and endorsed our earlier reports with substantial enhancement of in vitro and ex vitro by He-Ne laser irradiation.

Biotechnological Interventions in Litchi (Litchi chinensis Sonn.) for the Improvement of Fruit Quality and Postharvest Storage

Litchi (Litchi chinensis Sonn.) is an evergreen subtropical fruit, which is well acclaimed for its delicious, juicy aril and refreshing taste. Litchi fruit cultivation became an integral part of many Southeast Asian country’s economy and has a tremendous demand in domestic and export market. Insufficient genetic data about the native cultivar, poor knowledge and availability of the superior cultivars, lack of pest management control, and technological deficiency for the production and postharvest storage are the major constraints in litchi production and development all over the world. Biotechnological interventions have been successfully introduced in the field of litchi production for the massive micro-propagation, in vitro generation, and improvement of the quality of the available cultivars to produce superior cultivars with high yield. Widening of the genetic base of native cultivars using different molecular markers, introduction of genetic engineering to produce promising hybrids with large fruit, resistance to pericarp browning, and long life-span are highly recommended in this field with the help of biotechnological tools. In the present review, we have attempted to overview the combining research and development for the improvement of fruit quality and postharvest storage using various conventional as well as biotechnological tools.