Reduced Mean Germination Time Research Articles

SODIUM CHLORIDE PRIMING IMPROVES SALINITY RESPONSE OF TOMATO AT SEEDLING STAGE

We aimed to investigate whether sodium chloride seed priming and irrigation at seedling stage enhance response of 5-leaf stage tomato plants (Lycopersium esculentum Mill.) to high salt stress. Three experimental groups were as; non-primed seeds, seeds primed with 0.05M sodium chloride (NaCl), and seeds primed and irrigated with 0.05M NaCl starting from sowing to salt stress application. Sodium chloride solutions (0.1M, 0.2M, 0.4M, and 0.6M) were added to cups under pots in every 2 days for 10 days to treatment groups. Control groups were irrigated with distilled water at the same time intervals. At least two experimental setups contained at least four plants, and two samplings of leaf and root tissues were performed for analysis of each plant to evaluate changes in pigment and proline contents, lipid peroxidation and electrolyte leakage levels, and ascorbate peroxidase and catalase activity. Priming reduced mean germination time, and increased final germination percentage together with energy of germination. Increased root and hypocotyl lengths as well as increases in fresh weights supported enhanced seedling vigor. Considering growth and stress parameters such as chlorophyll content, chlorophyll to carotenoid ratios, and lipid peroxidation and electrolyte leakage were less affected in primed plants. Moreover, improvement of the accumulation of osmoregulating defense molecules, such as proline and anthocyanin, and of the inductions of the antioxidative enzyme system points out to higher adaptive response of these plants against deleterious effects of salt.

Impact of Intensity and Exposure Duration of Magnetic Field on Seed Germination of Tomato (Lycopersicon esculentum L.)

In order to study the effect of seed hydro priming and magnetic field on tomato seed germination an experiment was conducted in laboratory of Ferdowsi University of Mashhad, Iran, in 2010. The experimental treatments were all combinations of two levels of hydro priming (use of dry seed and soaked seed for five h in distilled water) and eight levels of magnetic field treatments (pretreatment of seeds in 15 mT for 5, 15 and 25 minutes, pretreatment of seeds in 25 mT for 5, 15 and 25 minutes, continuous magnetic field with 3 mT and control) with four replications. Results indicated that hydro priming of seeds reduced mean germination time significantly. Root length increased by 14 percent in seed hydro priming treatment in comparison with dry seed treatment. Shoot length, seedling length and vigor index of hydro primed seeds increased by 7, 12 and 13 percent, respectively compared with dry seeds. Exposure of seeds with 3 mT continuous magnetic field and 25 mT for 5 min increased root length by 29 and 25 percents, respectively in comparison with control. The highest shoot length, seedling length and vigor index were obtained in 3 mT continuous magnetic field and 25 mT for 5 min.

Seed priming influences weed competitiveness and productivity of aerobic rice

Growing rice under aerobic soil conditions is a promising water-wise technology under the context of ever-mounting water scarcity, but it is subject to poor stand establishment and high weed pressure. The present study was, therefore, designed to explore the possibility of adopting seed priming as a sustainable tool for weed management in aerobic rice. The trough experiment was established with aerobic rice line Aeron 1 considering four priming techniques: hydropriming, hardening, Zappa® priming and untreated control; and two weeding regimes: weed-free and weedy. Treatments were arranged in a randomized complete block design with four replications. Seed priming significantly improved germination attributes, weed suppressive ability and yield of rice, whilst unprimed control exhibited inconsistent germination, poor stand establishment and less weed competitiveness resulting in poor yield. Seed priming resulted in reduced mean germination time and increased germination percentage, germination index and seedling vigour index. Weed dry matter reduction by primed stand of rice ranged from 22% to 27% compared with control. A positive influence of seed priming was also evident in rice yield with an average increment of 0.4 t ha−1 over control. Weed-inflicted relative yield loss of rice was minimized by 10% as a consequence of seed priming. Zappa® solution emerged as the best priming agent, which demands its incorporation as a viable component in an integrated weed management strategy for aerobic rice.

Seed Priming Effects on Germination, Growth and Yield of Dry Direct-Seeded Rice

Insufficient seedling stand establishment is one of the major obstacles for achieving potential yield of dry direct-seeded rice (Oryza sativa L.). In the present study, seed priming technique was explored for improving germination and crop performance of dry direct-seeded rice. Seed-priming treatments used during the investigation included untreated control, hydro-priming, water hardening, and osmo-hardening with KCl. Priming reduced mean germination time and improved germination index, seedling vigor index, and germination energy. Hydro-priming was the best treatment, followed by water hardening, in improving seedling growth, leaf area index, panicles/m2, and grain yield of dry direct-seeded rice.

Population biology of Lilium polyphyllum D. Don ex Royle—A critically endangered medicinal plant in a protected area of Northwestern Himalaya

Lilium polyphyllum D. Don ex Royle, a Critically Endangered medicinal plant of the Himalayan Region is exploited for its roots to meet the demand of pharmaceutical industries. Over exploitation from the natural habitats has caused population depletion to a great extent. Therefore, population status of Lilium polyphyllum, effect of soil factors and associated species, and methods to improve seed germination were investigated. Species were sampled in habitats, seeds were collected and subjected to various treatments viz., soaking, chilling, plant growth regulators (indol acetic acid, indol butyric acid and gibbrelic acid) and chemical compounds (potassium nitrate and sodium hypochlorite). Lilium polyphyllum was recorded in only two habitats between 2338 and 2574 m with density range of 1–6.7 plants m −2. Density had significant correlations with soil moisture content ( r = 0.463, P < 0.05) and nitrogen ( r = −0.96, P < 0.01). In control conditions seed germination (35%) and Mean Germination Time (91 days) was poor. All the treatments applied to the seeds improved germination and MGT significantly ( P < 0.01) over control. Sodium hypochlorite (5 min) improved the germination percentage to 92% and indol acetic acid (100 μM) reduced mean germination time to 20 days. Species had high sensitivity to soil factors (i.e., nitrogen and moisture), non-native species and habitat destruction in natural habitats. Therefore, regular monitoring of its habitats, mass multiplication using germination protocol and transplantation are suggested to conserve the species.

Methods of braking seed dormancy on germination and early seedling growth of African locust bean (Parkia biglobosa) (JACQ.) Benth

An experiment was conducted under a net house in the department of Crop, Soil and Pest Management of the Federal University of Technology Akure. This was to investigate the most effective pre-sowing treatments to break seed dormancy, to stimulate seed germination and to identify morphological traits for the assessment of Parkia biglobosa seedling vigour. Matured seeds of P. biglobosa were collected from farmers in Akoko in Southwest Nigeria, dried at room temperature and tested for viability by floatation. The seeds were then subjected to pre-treatment that includes: soaking in 100% sulphuric acid for one minute, mechanical scarification with sandpaper, soaking in boiling water for two minutes, soaking in cold water (at room temperature) for 24 h. At 12 weeks, the seedlings growth parameters were assessed: seedling height, leaf production, and diameter and branch production. Result obtained shows that all the treatments except soaking in boiling water improved seed germination and reduced Mean Germination Time (MGT). The mechanical scarification appeared to be the most effective method of pre-treatment having the highest germination percentage 91.7%. Plant height appeared to be the strongest morphological trait to identify vigorous seedlings of P. biglobosa. Higher value of plant heights, number of leaves, branches and stem girth were recorded on the seedlings treated with scarification while hot water treated seeds performed low. This study revealed that seeds mechanically scarified improved seed germination and seedling growth. It is therefore recommended that mechanical scarification of the seeds of P. biglobosa may be effective for breaking dormancy and improving the seedling vigour which can enhance the domestication and cultivation of these valuable seeds in the environment. Key words: Parkia biglobosa, seed pre-treatment, mean germination time, seedling vigour index, scarification, morphological traits.