A three-factor experiment was set at the Horticulture Laboratory, Hajee Mohammad Danesh Science and Technology University, Dinajpur, to study the effects of the controlled deterioration (CD) on the pea seeds at the constant temperature of 35 ℃. The 3 factors considered were: 3 pea seed sources (Rangpur Local/RL, Dinajpur Local/DL and Thakurgaon Local/TL); 3 ageing periods (0, 8 and 16 days); and 3 seed moisture contents (12, 16 and 20% MC). The 27 treatment combinations compared in the CRD with the 3 repetitions for the 8 arenas were: % germination, % abnormal seedlings, % dead seeds, % soil emergence and seedling evaluation test for the root and shoot lengths as well as their dry matter contents. Identical prototypes of notable (5–1% level) degradations were recorded everywhere. But the disparities were lucid under the extreme stresses. Moreover, highly noteworthy (1% level) relations were traced amid all the traits ranging from -0.9847 (soil emergence × abnormal seedling) to 0.9623 (soil emergence × normal seedling). So, the CD technique was very effectual in judging the physiological statuses of the seed sources studied. Thus, the germination test might be add-on by a vigor test, the latter of which could be assessed by quantifying the seedlings’ root and shoot lengths and/or their dry matter accumulations. Moreover, in the seed quality certification, the suitable limits of vigor for the chosen traits could also be got by this technique. But the seeds of several pea varieties should be exploited to fix-up the agreeable limits of the traits. Furthermore, to save time, the ageing period could be squeezed by raising the seed MC.
Highly nutritive and antioxidants-enriched okra (Abelmoschus esculentus) gets sub-optimal field yield due to the irregular germination coupled with non-synchronized harvests. Hence, the research aimed at assessing the combined impact of seed priming and field-level gibberellic acid (GA3) foliar spray on the yield and post-harvest quality of okra. The lab studies were conducted using a complete randomized design (CRD), while the field trials were performed following a factorial randomized complete block design (RCBD) with three replications. Okra seeds were subjected to ten different priming methods to assess their impact on seed germination and seeding vigor. In the premier step, okra seeds were subjected to ten different priming methods, like hydro priming for 6, 12, and 18 h, halo priming with 3% NaCl at 35 ℃, 45 ℃, and 60 ℃, acid priming with 80% H2SO4 for 2.5, 5, and 10 min. Based on the observation, hydro priming for 12 h exhibited the best germination rate (90%), followed by halo seed priming at 60 ℃ and acid priming for 5 min. Furthermore, the halo priming at 60 ℃ demonstrated the greatest seedling vigor index (1965), whereas acid priming for 5 min resulted in favorable outcomes in terms of early emergence in 2.66 days. In addition, varying concentrations of GA3 (0, 100, 200, and 300 ppm) were also administered to the best three primed seedlings for evaluating their field performance. The findings indicated that applying GA3 at a concentration of 300 ppm to seedlings raised through acid priming (80% H2SO4 for 5 min) resulted in improved leaf length, reduced time to flowering (first and 50%) and harvest, increased pod diameter, individual pod weight, and yield per plant (735.16 g). Additionally, the treatment involving GA3 at 300 ppm with halo priming (3% NaCl) at 60 ℃ exhibited the longest shelf life (21 days) of okra with the lowest levels of rotting (6.73%) and color change (1.12) in the polyethylene storage condition.
The most crucial factor in producing papaya seedlings successfully is seed germination. The purpose of this study was to investigate the influence of seed priming with growing media on seed germination and seedling growth of papaya from October to December 2022. The experimental treatments included three seed priming treatments: T0 = control (no seed priming treatments), T1 = GA3 (100 ppm), and T2 = KNO3 (1%), and four growing media, viz., M1 = soil + vermicompost (1:1), M2 = soil + cowdung (1:1), M3 = soil + cocopeat + vermicompost (1:1:1), and M4 = soil + cocopeat + cowdung (1:1:1). The treatments showed a significant effect on different parameters such as germination percentage, days to germination, survival percentage, chlorophyll content, seed vigor index, shoot, and root length. GA3 treated seedlings performed better than non-GA3-treated seedlings. Among the growing media, M3 showed the best for seed germination and other growth attributes compared to other growing media. In terms of interaction effects, T1M3 showed the highest performance for germination percentage (84.33%), survival percentage (91.0%), and chlorophyll content (44.26%). T1M3 also showed the highest seed vigor index, shoot and root growth, and plant biomass. As a result, the combination of GA3 and growing media containing soil + cocopeat + vermicompost was shown to be the most favorable for papaya seed germination and seedling growth.
Beta macrocarpa, Guss is an interesting species showing very low germination rates. The leading objectives of this work were to investigate the dormancy mechanism and to find methods to break dormancy in order to achieve rapid, uniform and high germination. Macro and micro-morphologic analyses were performed by stereo microscopy and scanning electron microscopy showed two fruit coats. The yellow external coat or persistent perianth coat (PPC) was accrescent with 5 erect segments contiguous to the operculum of the seed capsule. This coat forms spongy layers (50 to 300 µm thick) that could be eliminated manually. The narrow internal coat or pericarp or achene coat (AC) forms woody joined seed capsules, each presenting a pressed operculum that cannot be manually opened. This coat was not adherent to seeds and was composed of compressed cells (50 to 200 µm thick) which form pockets for salt cristal. Seeds were lentiform (1 to 2 mm diameter and 0.5 to 0.8 mm thick) and highly fragile. The embryo was whitish surrounded peripherally by the perisperm with two highly developed cotyledons and radical. Polyphenol concentrations in both coats showed that after 4 months of collection, total polyphenol concentrations were 4-fold higher in the pericarp than in the persistent perianth. However, after one year, this parameter decreases significantly in the pericarp, whereas, it increases to a larger extent in the perianth. Different germination tests indicated that the pericarp provides a chemical and a physical resistance to seed germination during the first 4 months of the experiment after collection. The chemical dormancy was released to higher levels of total polyphenol compounds that inhibited seed germination and seedling growth. However, the physical dormancy was associated with the hardness of this intern coat which caused a mechanical resistance to radicle emergence. After one year of storage, total polyphenol pericarp concentration decreased notably, and chemical resistance disappeared, whereas the physical one persisted. Consequently, one year of storage pericarp removal is sufficient to break this exogenous dormancy.
The effects of Zn2+ stress on seed germination, seedling growth and chlorophyll content were studied in order to better understand the effect of heavy metal Zn on the growth and development of green plants. The concentration gradient of Zn2+ was 20, 50,100,150,200,300,500,700mg / L, and deionized water was used as control. The results showed that under the Zn2+ stress condition, the germination index of the rhubarb seeds increased with the increase of Zn2+ concentration. Germination potential, germination rate and germination index were the highest when Zn2+concentration was 100mg / L, the conductivity was the lowest at zinc concentration of 100mg / L, the root length, stem length and chlorophyll content of Zn2+ gradually reduced. The results showed that the amount of Zn2+ could promote seed germination, but the root length, bud length and chlorophyll content of seedlings could be affected by different degrees. The zinc fertilizer should be used in the production.
The use of bioproducts, economically viable, are of extreme importance in the protection and stimulation of germination in vegetable crops. This work evaluated the effect of the microorganisms Azospirillum brasiliense, Bacillus sub-tilis, Trichoderma harzianum and the commercial seed treatment product (Fipronil + Pilaclostrobin and Methyl Thiophanate) on seeds and seedlings of lettuce (Lactuca sativa), carrot (Daucus carota) and tomato (Solanum lycopersicum). The seeds were inoculated before being submitted to the germination test. The chemical treatment proved ineffective in protecting the seed of all crops and stimulating germination. T. harzianum increased the germination index of lettuce seeds, had better values in root system size in tomato crop and stimulated radicle emission in carrot. B. subtilis stood out in dry matter accumulation in tomato crop. The microorganisms B. subtilis and T. harzianum present potential for vegetable seed treatment.
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