Proline partially overcomes excess molybdenum toxicity in cabbage seedlings grown in vitro.

In vitro grown cabbage (Brassica oleracea var. capitata) seedlings exposed to excess molybdenum (Mo) ions exhibited severely reduced plant growth at the cotyledonary stage. Adding 80 mM proline (Pro) to the Mo-treated medium could help 50% seedlings to overcome the toxicity and grow true leaves. Under excess Mo stress, seedlings accumulated blue/purple anthocyanin in their cotyledons and hypocotyls. The anthocyanin content under Mo with 40 mM Pro was 4-fold higher than the control medium, MS with 40 mM Pro. The presence of Pro in the excess-Mo condition reduced chlorophyll a, whereas the chlorophyll b content was much higher than the control media of MS with and without Pro. Moreover, supplementing various concentrations of Pro into the Mo-stressed condition promoted the seedlings with higher antioxidant enzyme activities of superoxide dismutase, ascorbate peroxidate, and catalase. In addition, genes in the anthocyanin biosynthesis and accumulation pathways, phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), flavonone 3-hydroxylase (F3H), leucoanthocyanidin dioxygenase (LDOX), and glutathione-S-transferase (GST), were all upregulated. Our study indicated that, under excess Mo stress, the antioxidant activity of cabbage seedlings was induced in an attempt to protect plants from the Mo-induced toxicity and exacerbated growth. Pro, on the other hand, functioned in producing higher antioxidant enzyme activity to partially help recover plant growth.

Production of interspecific hybrids between commercial cultivars of the eggplant (Solanum melongena L.) and its wild relative S. torvum.

Interspecific hybrids between cultivars of eggplant (Solanum melongena L.) and its wild relative S. torvum, which has disease resistance and desirable traits for crop improvement, were obtained by cross-hybridization and embryo rescue. Twenty-one hybrid progenies were obtained and examined based on morphological traits, RAPD and ISSR markers. Five of them were confirmed to be true interspecific hybrids. Eighteen and 14 bands from 7 RAPD and 14 ISSR primers, respectively, were polymorphic and present in all five hybrid seedlings and their parents. The morphological characteristics of leaf margin, inflorescence type and spine positions of the five seedlings were intermediate to the parents. These interspecific hybrids had low pollen viability, probably due to abnormal meiosis.