• Journal of Plant Biotechnology
• /
• v.46 no.4
• /
• pp.318-322
• /
• 2019

When dehulled apple seeds (Malus pilmila var. domestica) were induced to germinate, the rate of germination, which was increased by piercing both the radicle and cotyledon, was related to the site of injury. Also, the germination rates of an embryo with ¾ cotyledon (¾ CE), embryo with ½ cotyledon (½ CE), embryo with ¼ cotyledon (¼ CE), and embryo without cotyledon (NCE) gradually decreased compared to an embryo with a normal cotyledon, but it significantly recovered on the agar media containing MS solution and/or 80 mg/L gibberellin (GA₃) as nutrition. The results show that the germination of the embryo was inhibited by the partial removal of cotyledon and also demonstrated that the rate of germination could be significantly increased by adding GA₃ (80 mg/L) and/or MS medium.

• Journal of Plant Biotechnology
• /
• v.36 no.2
• /
• pp.149-156
• /
• 2009

Application of exogenous polyamines (PAs) reduced the paraquat (PQ)-induced cotyledon injuries in radish seedling plants with 1 mM spermidine (Spd) being the most effective protectant. PQ injury symptoms in the cotyledons, e.g., large accumulation of $H_2O_2$, and losses of fresh weight, chlorophyll, and proteins, were significantly alleviated. Likewise, analysis of $H_2O_2$-scavenging enzymes such as catalase (CAT) and guaiacol peroxidase (GPX) showed that pretreatment with Spd among PAs remarkably increased total CAT activity and strongly retarded PQ-induced rapid decline in total GPX activity. In a native gel assay, one CAT isozyme (CAT1) and two GPX isozymes (GPX1 and a newly synthesized GPX isozyme) proved to be more responsible for PQ tolerance, as manifested by the strong increases in their activities by Spd pretreatment. Based on these results, we can suggest that PAs (especially 1 mM Spd) may function as antioxidant protectors by invoking CAT and GPX enzymes which control the endogenous $H_2O_2$ level in radish cotyledons exposed to PQ.

• Korean Journal of Weed Science
• /
• v.6 no.2
• /
• pp.191-200
• /
• 1986

The study was conducted to screen paraquat-tolerant plant species among crops and weeds, using the response of plant like leaf disc discoloration, visual injury and dry weight in the presence of paraquat. Mechanism of paraquat-tolerance was investigated in strains of soybean through evaluating activities of superoxide dismutase and peroxidase and the multiplication of callus derived from soybean cotyledon. In crops, Kwanggyo has been selected as a paraquat-tolerant variety among soybean cultivars tested, and Hood as a susceptible one. In weeds, Polygonum aviculare, Chenopodium album and Pinellia ternata were evaluated as the paraquat resistant species, providing the possibility for the donor plant species for paraquat resistance. Activity of superoxide dismutase known to detoxify paraquat was markedly greater in Kwanggyo, a paraquat-tolerant cultivar than in Hood, a susceptible one. In addition, the similar response like superoxide dismutase was observed in peroxidese activity. The greater inhibition of callus multiplication was determined in Hood, a susceptible one than a tolerant one, Kwnggyo. Based on all the informations, it is strongly proposed that paraquat tolerance in soybean is due to destruction of $O_2^-$ by elevated concentration of superoxide dismutase in the tolerant cultivar.