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Abstract

Due to the existing threat of use of CWA, many countries developed special chemical formulations dedicated to remove CWA - the so-called military decontaminants. The function of the decontaminant is to neutralize the toxic properties of the contaminant through chemical reactions: oxidation and nucleophilic substitution.

The decontaminants released to the environment may transform to toxic products which have a harmful impact on plants and other soil biota. To evaluate the impact of these chemicals on plants phytotoxicity, early growth tests with Sinapis alba, Lepidium sativum and Sorghum saccharatum were used. Parallely with standard toxkit endpoints (seed germination and root elongation, data not presented here), seed vigor indexes and germination indexes were calculated. GI is a more sensitive endpoint in phytotoxicity testing than SVI. The EC50-72h values based on GI are about 2-3 times lower than those based on SVI. Very low PNEC soil values indicate that wide usage of such compositions in case of CWA release will cause damage to vegetation in the environment.

Abstract

A laboratory experiment regarding germination and seedling growth test was conducted with three black gram genotypes tested under three salinity levels (0, 75 and 150 mM), for 10 days, in sand culture within small plastic pot, to investigate the germination and seedling growth characteristics. Different germination traits of all black gram genotypes, like germination percentage (GP), germination rate (GR), coefficient of velocity of germination (CVG) greatly reduced, as well as mean germination time (MGT) increased with increasing salt stress. At high salt stress, BARI Mash-3 provided the highest GP reduction (28.58%), while the lowest was recorded (15.79% to control) in BARI Mash-1. Salinity have the negative impact on shoot and root lengths, fresh and dry weights. The highest (50.32% to control) and lowest reduction (36.39%) of shoot length were recorded in BARI Mash-2 and BARI Mash-1, respectively, under 150 mM NaCl saline conditions. There were significant reduction of root lengths, root fresh and dry weight, shoot length, shoot fresh and dry weight in all genotypes under saline condition. The genotypes were arranged as BARI Mash-1 > BARI Mash-3 > BARI Mash-2, with respect to salinity tolerance.

The Alleviation Effect of Silicon on Seed Germination and Seedling Growth of Tomato Under Salinity Stress

This study was conducted to evaluate the effectiveness of silicon (Si) application under salinity levels on seed germination and growth characteristics of tomato seeds. A laboratory experiment was performed on completely randomized design with two levels of salinity (25 and 50 mM NaCl) and 2 concentration of Si (1 and 2 mM) with 4 replications. Germination percentage, germination rate, seedling shoot and root length, fresh and dry weight of seedling and mean germination time was measured. Seed germination of Lycopersicon esculentum L. was significantly affected by salinity levels, Si and their interaction. Germination characteristics of tomato seeds decreased drastically by increasing NaCl concentrations. However, 1 mM Si had positive effects on seed germination characteristics and improved germination percentage, germination rate and mean germination time. Si alleviated the harmful effect of salinity stress on tomato seed germination at almost all germination characteristics.

Abstract

In order to study the plant growth regulator, using salicylic acid (SA) on germination and growth indices for laboratory research in crop year 2014-2015, which was conducted at the research center Safiabad-Dezful, Khuzestan province. The treatments included four levels of priming with salicylic acid {control (distilled water), 0.7, 1.2, 1.7 mM} in a completely randomized design in three replications. The results showed that the control treatment reduced the decrease in germination time. The highest percentage of germination and related characteristics of the control (distilled water) was obtained. Seed vigor and seedling vigor index were reduced in high concentrations of salicylic acid. The germination percentage of an average daily germination, seed vigor and seedling vigor index had a positive and significant correlation with the daily germination rate showed a significant negative correlation. The results of comparison of treatments showed that the treatment concentration of 0.7 mM salicylic acid highest (22.3 days) and control (distilled water) lowest (0.3 day) had mean germination time. Effects of priming showed the highest mean daily germination (15.44) related to the control and the lowest (2.97) related to the concentration of 7.1 mM salicylic acid. Also, the results showed that the 1.7 mM salicylic acid treatment had the highest number of germinated seeds per day (0.3880) and control treatment had the least number of germinated seeds per day (0.6467). The highest vigor index was observed in control treatment with seedling length of (8.15 cm) and the lowest vigor index was observed in 1.7 mM salicylic acid treatment with seedling length of (1.54 cm). The highest seedling vigor index was observed in control treatment (33.58) and the lowest seedling vigor index was observed in 1.7 mM salicylic acid treatment (17.20). The coefficient velocity germination rate in control treatment was highest (3) and in the 1.7 mM salicylic acid treatment was lowest (0.15). The correlation coefficient between vigor index and seedling vigor index has the highest value (98%). There was a positive correlation between germination percentage and mean daily germination and there was a negative correlation between germination percentage and daily germination speed.

Abstract

Seed priming is one of the methods that can be taken to counteract the adverse effects of abiotic stress, also Seed priming treatments have been used to reduce the damage of aging and invigorate their performance in many crops. Objective of this study was to evaluation the effect of gibberellin on germination characteristics and antioxidant enzymes of safflower seeds after aging. Experimental design was a factorial one with complete randomized design with three replications. The first factor was priming by gibberellin (0 and 50 ppm) and non-primed seeds (control) and the secondary factor was combinations of four levels of aging (0, 1, 3 and 5 days of aging, at 43°C). The results showed that the priming and aging effects on germination percentage, germination index, normal seedling percentage, seedling length, vigor index, catalase and ascorbate peroxidase were significant, but on mean time to germination not significant. Results showed that, the highest germination characteristics such as; germination percentage, germination index, normal seedling percentage, seedling length, vigor index, catalase and ascorbate peroxidase were attained from priming by gibberellins, under non aged conditions. Also, our results indicated that seed aging is related to decrease of enzymes activity and may contribute to low seed germination efficiency, also priming increases enzyme activity and increases enzyme activity with priming treatment may contribute to improve germination characteristics. The general decreases in enzyme activity in the seed lowers the respiratory capacity, which in turn lowers both the energy (ATP) and assimilates supply of the germinating seed.

Abstract

Seed priming techniques have been used to increase germination, improve germination uniformity and seedling establishment under stressed conditions. Seed priming was used in rye mountain (Secale montanum) to increase seed germination and tolerance on stress exposure (Cold stress). Rye seeds were treated with water (Hydro priming) and polyetelyn glycol 6000 (Osmo priming). The effect of priming was assessed on germination characteristics under cold stress (at 3°C) for 7 days. Analyze of variance for hydro priming showed that temperature × time of priming interaction was significantly (P < 0.01) for all traits under cold stress and for osmo priming showed that Concentration of PEG × Temperature × Time of priming interaction was significantly (P < 0.01) for all traits under cold stress except seedling dry weight (SDW). For hydro priming the highest germination percentage (GP) was attained from hydro priming at 15±1°C for 16 h (70%), whereas the highest normal seedling percentage (NSP) (22.5%), germination index (GI) (8.57), seedling vigor index (SVI) (38.9) and seedling length (SL) (1.7 cm) were in the hydro priming at 10±1°C for 16 h. For osmo priming the highest germination percentage (GP) (80 and 80.5%), normal seedling percentage (NSP) (48 and 45%), seedling vigor index (SVI) (101.26 and 85.25) and seedling length (SL) (2.11 and 1.89 cm) observed in the osmo priming with concentrations of -9 and -15 bar PEG at 15±1°C for 24 h.

ABSTRACT

The feasibility of extending the storability of fresh hot pepper seeds, by modifying the storage atmosphere, using the respiration inhibitors and seed desiccants was examined. Halogens such as chlorine, bromine and iodine and methanol, ethanol and potassium permanganate were used for a period of 22 months under accelerated ageing conditions of high seed moisture and temperature. The various seed quality parameters - viability, vigour, speed of germination, seedling dry weight, and moisture content were evaluated. In the untreated control, decreased seed viability was observed within 10 months of storage. However, iodine and chlorine were proved effective in retaining high seed viability up to 90.7 and 88.0%, respectively, even after 22 months of storage. Chlorine treatment was able to retain the seed vigour (904.0), iodine (766.4), KMnO4 (754.4) and methanol (566.7) whereas the value of vigour index in control was 72.0. Chlorine and iodine were on par in their ability to maintain the speed of seed germination (25.2 and 24.8, respectively), followed by KMnO4 (20.2). Seedling dry weight was proved as a parameter not sensitive in estimating the seed quality since even after 22 months storage of seeds at atmospheres of chlorine, iodine, KMnO4 and methanol did not show any differences. KMnO4 sharply reduced the seed moisture content from 9.83 to 7.89% providing better storability over the control.

Abstract

The period of vegetation and flowering of carrot usually is very long, and the flowers are formed in different parts of the mother plants. This leads to the formation of seeds with different qualities. Often heterogeneity is of a maternal type, which depends on the position of the umbels on the mother plants. The main goal of the present study was to investigate the quality differences in carrot seeds from different parts of the mother plant. The seedstalks from ‘Nantski’, a typical Bulgarian cultivar, were grown by the conventional method for seed production technology. In botanical maturity the seeds from the primary, secondary and tertiary umbels were extracted separately. The seed yield from umbels, dry weight of the seeds, seed size, length, width and thickness, weight per seed, 1000 seed weight, germination energy (first count), germination capacity (final count), mean germination time, uniformity of germination, fresh weight of seedlings, length of radicle, length of hypocotyls and vigour indexes were investigated. The contents of raw protein, sugar, lipids and the basic calorific values were also analysed. The germination was the highest for the seeds from primary umbels, followed by the ones from secondary umbels and lowest for those from the tertiary umbels. The difference between the highest and the lowest value was 6.30%. These results suggest that it is better to harvest the carrot seeds depending on their position on the plant and divide them into separate lots with different qualities.

Abstract

Silicon is one of the most widespread macro elements that have beneficial effects on plant growth. Although its positive effects on plant growth and development have been widely considered, little information is available about possibility of nano-silicon utilization in seed invigoration treatments. Enhanced seed germination may lead to improved stand establishment and it can play important role in successful crop production. Partial hydration of the seeds followed by dehydration in a controlled environment often results in rapid seed germination and more uniform seedling emergence compared to untreated seeds. In the present study, the effect of seed soaking in different concentration nano-silicon solutions (0, 0.2, 0.4, 0.6, 0.8, 1 and 1.2 mM for 8 h) on germination characteristics of sunflower was investigated. Seed soaking in low concentration nano-silicon solutions (0.2 and 0.4 mM) significantly reduced days to 50% germination and mean germination time and improved root length, mean daily germination, seedling vigour index and final germination percentage. These results suggest that the incorporation of nano-silicon in priming solution, in an appropriate concentration, remarkably enhances germination performance and causes an effective invigoration of the seedling. These results underline the importance of pre-sowing seed soaking in diluted nano-silicon solutions for improving the germinability of sunflower.

ABSTRACT

Seed priming with gibberellin (GA) enhances seed germination performance; but the quality of primed seeds in aging condition often reduces more than non-primed seeds. An experiment was conducted to evaluate the effect(s) of heat shock treatments on germination characteristics and enzyme activity of primed mountain rye (Secale montanum) seeds with gibberellin under accelerated aging. Heat shock treatments, can substantially decrease the speed of quality reduction of mountain rye (Secale montanum) primed seeds. In primed seeds with gibberellin, which has non-aged, the highest germination percentage (GP) and normal seedling percentage (NSP) was attained from heat shock treatment at 35°C for 3 h, also after 3 days aging, it was attained from heat shock treatment at 35°C for 3 h. After 3 days of aging the highest germination index (GI) was attained from unprimed seeds, but no significant difference with heat shock treatment at 35°C for 3 h. The minimum means time germination (MTG) was in heat shock treatment at 30°C for 3 h in non-aged seeds. After 3 days of aging, heat shock treatment reduce MTG as compared to the primed seeds. Heat shock treatment at 35°C for 3 h increased seed vigor index (SVI) as compared to the unprimed and primed seed in non-aged seeds and after 3 days aging. Seedling length (SL) increases with heat shock treatment at 30°C for 4 h in non-aged seeds as compared to the primed and unprimed seeds, but after 3 days of aging heat shock treatment except at 35°C for 3 h and 40°C for 4 h reduced SL as compared to the primed and unprimed seeds. Also, heat shock treatments increase some antioxidant enzymes [Catalase (CAT), Ascorbat peroxidase (APX)].