S. M. A. Basra

Enhancing the Performance of Direct Seeded Fine Rice by Seed Priming

Abstract Higher water requirements and increasing labor costs are the major problems of the traditional rice production system. Direct seeded rice culture, growing rice without standing water, can be an attractive alternate. However, poor emergence and seedling establishment, and weed infestation are the main hindrances in the adoption of this culture. An attempt to improve the performance of direct seeded rice by seed priming was made in the present study. Priming tools employed were traditional soaking (soaking in tap water up to radicle protrusion), hydropriming for 48 h, osmohardening with KCl or CaCl2 (osmotic potential of – 1.25 MPa) for 24 h, vitamin priming (ascorbate 10 ppm) for 48 h and seed hardening for 24 h. All the priming techniques improved crop stand establishment, growth, yield and quality except traditional soaking, which resulted in impaired germination and seedling establishment that ended in reduced kernel yield and lower harvest index than that of control. Early and synchronized germination was accompanied by enhanced amylase activity and total sugars. Osmohardening with CaCl2 resulted in the best performance, followed by hardening and osmohardening with KCl. Osmohardening with CaCl2 produced 2.96 t ha-1 (vs 2.11 t ha-1 from untreated control) kernel yield, 10.13 t ha-1 (vs 9.35 t ha-1 from untreated control) straw yield and 22.61% (vs 18.91% from untreated control) harvest index. Mean emergence time and emergence to heading days, germination percentage and panicle bearing tillers; plant height and straw yield, 1000-kernel weight and kernel yield, α-amylase activity and total sugars, kernel proteins and kernel water absorption were correlated positively.

Changes in nutrient-homeostasis and reserves metabolism during rice seed priming: consequences for seedling emergence and growth.

Abstract In this study influence of different seed priming treatments on the nutrient-homeostasis and reserve metabolism during seedling emergence and growth of rice were determined. Seed priming treatments included pre-germination, hydropriming for 48 h, osmohardening with KCl and CaCl 2 , ascorbate priming and hardening. All treatments shortened the emergence time and enhanced the energy and index of seedling emergence. Seedlings from primed seeds had greater length, number of roots and fresh and dry mass than control. Among the treatments, CaCl 2 , ascorbate and KCl proved better in enhancing emergence and seedling growth. Seed priming changed the pattern of N and Ca 2+ homeostasis both of the seeds and seedlings, which were associated to enhancing α-amylase activity and reducing sugars content. Positive correlations of seedling attributes with nutrient content suggested that as a result of seed priming, most of N and Ca 2+ were partitioned to embryo, which enhanced seedling emergence and subsequent growth of rice seedlings.

Seed Enhancement of Silybum marianum and Optimization of Silymarin Extraction

The present study elucidates the impact of different priming strategies on seed emergence and growth of milk thistle [Silybum marianum (L.) Gaertn.] and also evaluation of the efficacy of various extraction methods for optimal extraction of silymarin from milk thistle seeds. Seeds were primed with distilled water, Humic acid (2%), potassium chloride (2%) and moringa leaf extract (3%) for 24 h. Untreated seeds were used as control. Primed and non-primed seeds were sown in plastic pots. Seed priming treatments significantly improved the performance of milk thistle seeds as indicated by higher values of final emergence and lower values of mean emergence time and time taken to 50% emergence as compared to non-primed seeds. Silymarin was extracted from seeds of milk thistle by applying various techniques like Reflux, Soxhlet, maceration and microwave assisted extraction by using various solvents. Extraction with Soxhlet and microwave assisted techniques were proved better as compared to the others. The results indicated that in both spectrophotometric and HPLC quantification, silymarin contents were found maximum in extracts prepared with methanol by microwave assisted extraction technique followed by Soxhlet.

Drought affects size, nutritional quality, antioxidant activities and phenolic acids of Moringa oleifera LAM.

To observe variation in growth performance, antioxidant activities, and nutritional quality of Moringa oleifera, we exogenously applied benzyl amino purine (BAP), ascorbic acid, and moringa leaf extract (MLE) to moringa plants at three field capacity levels, 100, 75, and 40% in a completely randomized design with three replications. We observed a decrease in growth, chlorophyll a and b, total phenolic contents, antioxidant activities, crude protein, and mineral contents of moringa leaves at 100 and 40% field capacity in comparison with 75% field capacity. BAP best improved growth performance of moringa plants, improving shoot length, root length, number of leaves and photosynthetic pigments, followed by MLE at 75% field capacity, while moringa plants showed reduced growth at 40% field capacity which was increased by BAP and MLE foliar application. Maximum contents of gallic acid, p-coumaric acid and sinapic acid were found in moringa leaves when the plants were sprayed with ascorbic acid while p-hydroxybenzoic acid and caffeic acid were maximally increased under 75% field capacity when the plants were subjected to BAP followed by MLE. The lowest and highest crude protein, calcium, potassium, magnesium, and phosphorous contents were recorded under 40 and 75% field capacity, with MLE impro-ving these contents under both conditions. It can safely be concluded that moringa plants showed retarded growth under 100 and 40% field capacity, and that the effects of deficit in nutritional quality were mitigated by applying BAP and MLE. Among these two plant growth regulators, MLE can be preferred being a natural source.