Sulfur Fertilization Influence on Growth and Yield Traits of Three Korean Soybean Varieties

Field experiment was carried out at the Research Farm of Korea University, Republic of Korea to study effects of sulfur (S) fertilization on growth traits, yield and yield components of three Korean soybean varieties (Poongsunnamulkong, Saedanbaekkong and Daewonkong). Seeds were sown on black polythene mulched soil bed at the spacing of 15 X 60 cm both at control and sulfur fertilized (gypsum with 16% sulfur content at the rate of 200kg ha-1) plots following a Randomized Complete Block Design of the experiment applying three doses of sulfur together at the time of seed sowing and two doses together at V4 vegetative growth stage (4 nodes on the main stem beginning with the unifoliate node). The results showed that sulfur fertilization significantly increased all studied growth traits of three Soybean varieties except plant height when they all reached physiological maturity stage (120 DAS). It was also evident that sulfur fertilization in the form of gypsum can also increase the number and weight of soybean root nodules and enhance the ability of nitrogen fixation, and so reduce the input of nitrogen fertilizer. Similarly, all the studied yield and yield component related parameters were also significantly influenced by sulfur fertilization except seed number per pod and 100 seed weight. Varieties and sulfur fertilization also interacted significantly in all studied growth traits but the notable sole interaction effect was in plant height. Leaf area of Poongsunnamulkong and Saedanbaekkong variety increased significantly with sulfur fertilization while it was decreased significantly for Daewonkong. Similar trend was observed in their production of number of pods per plant and grain yield per plant indicating leaf area increment by sulfur fertilization played an important role in increasing yield of Poongsunnamulkong and Saedanbaekkong varieties though their performance was reverse in other growth traits. The improvement in growth and yield attributes after sulfur fertilization led to higher biological yield and enhanced seed yield

Effect of polyethylene glycol and mannitol on somatic embryogenesis of pigeonpea, Cajanus cajan (L.) Millsp.

A protocol for high frequency somatic embryogenesis (SE) of pigeonpea, Cajanus cajan (L.) Millsp. was worked out. The age of the source seedlings for explants and type of explants were found to influence the callusing response. Concentration of phytohormones and growth factors were optimized for developing embryogenic callus consisting of globular cells with dense cytoplasm. Embryo axis or callus derived from such explants, when exposed to dehydration stress imposed by polyethylene glycol and osmotic stress created by D-mannitol were found to produce high frequency somatic embryos. Embryo axis from 3-day old sprouts or 28-day old callus derived from the embryo axis explants incubated for 4 h either in 4% polyethylene glycol (w/v) or 0.7 M mannitol were found optimal for SE. After exposure to stress incubation, explants or callus were cultured on semisolid Murashige and Skoog (MS) + 2,4-dichlorophenoxy acetic acid (2,4-D) (5 μM) + glutamine (0.03 mM) and the cultures formed only globular and heart shaped somatic embryos. The early stage somatic embryos subsequently developed into torpedo and cotyledonary somatic embryos in MS liquid medium supplemented with 2,4-D (2 μM), abscisic acid (3 μM) and glutamine (0.03 mM). The somatic embryos were converted into plantlets in hormone-free half-strength MS semisolid medium and subsequently established in garden soil.Key words: Abscisic acid, glutamine, osmotic stress, polyamines, water stress

Induction of high frequency somatic embryogenesis and analysis of developmental stagewise expression of <em>SERK1</em> gene during somatic embryogenesis in cultures of <em>Vigna radiata</em> (L.) R.Wilczek

180-193Vigna radiata (L.) R.Wilczek (Fabaceae), commonly called Green gram or Mung bean, is an important legume with potential nutritional, medicinal and health benefits cultivated widespread throughout the rain-fed areas of arid and semi-arid tropics and subtropics. Being an affordable source of carbohydrate, vitamins, minerals and phytonutrients besides protein, Green gram finds demand for its nutrient digestibility, food processing properties and bioavailability. Though India ranks top in world mung bean production (>50%), it is unable to meet the local demand. Biotic and abiotic stresses restrict mung bean yield considerably and researchers have been working on resistant varieties to overcome these challenges. In this study, towards improving yield, an effective protocol for attaining high frequency somatic embryogenesis (SE) in green gram has been proposed. Type of explants and age of source seedlings for obtaining explants were found to influence the formation of embryogenic calli. Various combinations and concentrations of 2,4-dichlorophenoxyacetic acid and indole-3-acetic acid with kinetin were optimized for developing embryogenic calli. Embryogenic calli when exposed to osmotic stress created by D-mannitol and sorbitol and dehydration stress imposed by polyethylene glycol were found to produce somatic embryos. Calli incubated for 6 h in specified hormone free nutrient medium supplemented with 4% polyethylene glycol was optimal for induction of high frequency SE. Subsequent to stress incubation, the cultures formed only early stage somatic embryos. Supplementation of proline was found essential for the maturation of somatic embryos. Cotyledonary stage somatic embryos were converted into plantlets and subsequently established in garden soil. Semi-quantitative Reverse Transcription-PCR based transcript level analysis of SERK1 gene expression was carried out during different developmental stages of somatic embryogenesis. Expression of SERK1 was specifically associated with the embryogenic calli and calli enriched with globular stage somatic embryos

Reactive oxygen species in plants: their generation, signal transduction, and scavenging mechanisms,”

Abstract Reactive oxygen species (ROS) are a by-product of normal cell metabolism in plants; however, under stress conditions, the balance between production and elimination is disturbed. ROS rapidly inactivate enzymes, damage vital cellular organelles in plants, and destroy membranes by inducing the degradation of pigments, proteins, lipids and nucleic acids which ultimately results in cell death. In addition to degrading macromolecules, ROS act as a diffusible signal in signal transduction pathways and also as a secondary messenger in various developmental pathways in plants. Plants possess a complex battery of enzymatic and non-enzymatic antioxidative defense systems that can protect cells from oxidative damage and scavenge harmful ROS that are produced in excess of those normally required for various metabolic reactions. The mechanism by which ROS is generated in aerobic organisms is poorly understood. This review paper describes the generation, origin, and role of ROS in signal transduction and cell death, and the removal of ROS by antioxidative defense systems in plants during various developmental pathways