Interferences of Inorganic Arsenic (III & V) on Growth and Development of Rice (Oryza sativa L.) With Special Emphasis on Root and Coleoptile Growth

A short-term phytotoxicity experiment was conducted on four varieties of rice (Oryza sativa L.) under the influence of arsenic (III & V) to evaluate the impact on root and coleoptiles growth. Four varieties (GB-1, IET-4786, IET-4094, and MTU-1010) of rice were undertaken for this study with different concentrations (0, 5, 10, 25 and 50 mg/L) of arsenic (III & V). Germination along with mean daily germination (MDG), length of root and coleoptile, water holding capacity of root and coleoptiles, fresh and dry weight, arsenic accumulation, MDA and root ion leakage were evaluated. Results highlighted that the percent germination of IET-4094 and MTU-1010 varieties of rice seed over control decreased significantly (p < 0.05) with increasing concentration of both arsenite and arsenate. However, the percent germination of GB-I and IET-4786 dose not affected on the different concentration of both arsenate and arsenite. The root and coleoptile length of all the four varieties showed remarkable decreasing trend over control with increasing concentration of both arsenite and arsenate. However, more pronounced effects were observed for arsenite than arsenate. Similarly, biomass of shoot is less affected than root under different concentration of arsenite and arsenate. The variety IET-4786 and MTU-1010, accumulated lower level of arsenic and variety GB-1 accumulate higher level of MDA level in root under both arsenite and arsenate treatments. Therefore, it can be concluded that the variety IET-4786 and MTU-1010 are the suitable varieties towards phytoremediation of both arsenite and arsenate. Moreover, farmers of arsenic contaminated area are recommended to cultivate IET-4786 and MTU-1010 varieties.

​Effect of Seed Treatments and Storage Period on Seed Health Parameters of Pea (Pisum sativum L.) under Ambient Storage Conditions

Background: Pea (Pisum sativum L.) is an important leguminous crop utilized as vegetable and pulse, being an important source of proteins. Pea seeds harbour various mycoflora both in field and during storage, which plays important role in reducing seed viability, germination and vigour inflicting considerable losses in yield and quality. There is scarcely any recommendation available to maintain seed quality during storage of pea seeds, hence present study was carried out. Methods: Seeds of pea (cvs. Azad P. 1 and Arkel) were treated with Captan and Carbendazim 50%WP fungicides @ 2.0 g/Kg seed and stored under ambient conditions. The samples were drawn at three months interval to assess the effect of storage on seed quality parameters. The vigour index I, per cent germination and speed of germination of these seed samples were determined using ISTA rules. The detection of associated mycoflora in pea (Pisum sativum L.) seed samples was carried out by standard blotter method as recommended by International Seed Testing Association. Result: Total fourteen fungal species were found associated with different pea seed samples. Out of these, maximum incidence of Alternaria alternata (21.36%) followed by Aspergillus flavus (15.53%), A. fumigatus (14.56%), A. niger (11.60%) and Rhizopus stolonifer (9.71%), were recorded on untreated seed of pea cv. Azad P. 1, after 18 months of storage. The germination, speed of germination and vigour index of stored seed reduced with increase in storage period, whereas fungal incidence increased with the increasing storage period. Among the tested cultivars, germination in pea (cv. Arkel) remained above IMSCS even after 18 months of storage under ambient storage conditions. The maximum percent germination (99.0) was found in pea cv. Azad P. 1 seeds treated with Captan at 3 months of storage, whereas minimum percent germination (49.5) was found in untreated seed of pea cv. Azad P. 1 after 18 months of storage. The maximum speed of germination (23.88) was found in Captan treated seed of pea cv. Arkel at 0 month of storage and minimum speed of germination (3.52) was found in untreated seed of pea cv. Azad P. 1 at 18 months of storage. The maximum vigour index I (2339) was found in pea cv. Azad P. 1 (Captan treated seed) at 3 months of storage and minimum vigour index I (431) was found in untreated seed of pea cv. Azad P. 1 after 18 months of storage.

Effect of different growing media on seed germination and seedling growth of jamun (Syzygium cumunii L. Skeels)

The study entitled “Effect of different growing media on seed germination and seedling growth ofJamun (Syzygium cumunii L. Skeels)” was carried out at College of Horticulture, Dr. Y.S.R Horticultural University, Venkataramannagudem, West Godavari District, AndhraPradesh, during the year 2018-19.Jamun seeds were sown in media comprising of soil, cocopeat and vermicompost in different ratios, Among which the media comprising of Soil + cocopeat + vermicompost @ 1:1:1 has shown best results in germinationparameters like earlier initiation of germination(10.91 days), less days taken to 50 percent germination(14.5 days) , highest percent of germination at 15 and 30 DAS(48.37% and 98.14 % respectively). The growth parameters likemaximum plant height(96.33cm), more number of leaves(55.75), increased girth(7.58mm) and chlorophyll content, lengthiest primary root(25.82cm), more number of secondary roots per seedling(41.51), highest fresh and dry weight of the shoot(80.24 and 20.67g.) and root and good root: shoot ratio(0.28)at 150 days after sowing were observed in plants that were sown in media comprising of Soil + cocopeat + vermicompost @ 1:1:1.

Endozoochory and Germination of Selected Ingested Seeds by Malayan Box Turtles (Cuoraamboinensis) from Laguna Province, Philippines

Aims: Malayan box turtles’ (Cuoraamboinensis) ecological niche are essential in an ecosystem but are often overlooked. This study investigated the germination of selected seeds that passed through the gut of Malayan box turtles to determine its role in promoting seed dispersal and aiding seed germination. Study Design:Experimental approach. Place and Duration of Study:Pamantasan ng Lungsod ng Maynila (University of the City of Manila) and Dasmarinas, Cavite between June 2016 to March 2017. Methodology: The seeds that passed through the turtle’s gut (Gut Passed Seeds) and seeds that did not pass through its gut (Mechanically Extracted Seeds) underwent comparative germination test. The Germination Rate (GR) and Percent Germination (%GR) of each group were determined in the study.Seed shadowing was also conducted to evaluate the turtle’s seed dispersal capacity (endozoochory). Results: Results showed that after gut passage, seed GR and %GR were enhanced on Lycopersiconesculentum, Carica papaya, Psidiumguajava, and Muntingiacalabura. However, Germination Rate and Percent Germination of Passifloraquadrangularis decreased after gut passage. Statistical analyses revealed that there is a significant difference in the GR and %G of M. calabura and %G of L. esculentum, and P. quadrangularis. Thread trailing method showed that C. amboinensis can disperse seeds at a distance of 24.8 to 52.8 meters. Conclusion: This study demonstrates the important role of C. amboinensis in the ecosystem through its contribution to plant seed germination and dispersal.It showed that Malayan box turtles are not only seed dispersal agents but are also important in the germination of seeds that they have ingested and defecated.

Terrestrial Morphotypes of Aquatic Plants Display Improved Seed Germination to Deal with Dry or Low-Rainfall Periods

In temporary ponds, seed germination largely determines how well aquatic plant assemblages recover after dry periods. Some aquatic plants have terrestrial morphotypes that can produce seeds even in dry years. Here, we performed an experiment to compare germination patterns for seeds produced by aquatic and terrestrial morphotypes of Ranunculus peltatus subsp. saniculifolius over the course of five inundation events. During the first inundation event, percent germination was higher for terrestrial morphotype seeds (36.1%) than for aquatic morphotype seeds (6.1%). Seed germination peaked for both groups during the second inundation event (terrestrial morphotype: 47%; aquatic morphotype: 34%). Even after all five events, some viable seeds had not yet germinated (terrestrial morphotype: 0.6%; aquatic morphotype: 5%). We also compared germination patterns for the two morphotypes in Callitriche brutia: the percent germination was higher for terrestrial morphotype seeds (79.5%) than for aquatic morphotype seeds (41.9%). Both aquatic plant species use two complementary strategies to ensure population persistence despite the unpredictable conditions of temporary ponds. First, plants can produce seeds with different dormancy periods that germinate during different inundation periods. Second, plants can produce terrestrial morphotypes, which generate more seeds during dry periods, allowing for re-establishment when conditions are once again favorable.

Assessment of Arsenic Toxicity in Spinacia Plant: Physiological Aspect

Arsenic (As) is a chemical element which has become environmental toxin now days due its presence in large concentration in water and soil. It remains in the environment for an extensive period. Although it is a non-essential element for plant, the rooted plants absorb Arsenic from the soil. Even a trace amount of Arsenic is enough for affecting the plant growth and development. Test sample Spinacia sp. is a green leafy vegetable that belongs to the family Amaranthaceae. It is distributed all over the world. It is a good source of minerals, vitamins, ascorbic acid, carotenoids, phenols and omega 3fatty acid, therefore, called as the power house of nutrients. Background soil prepared with the Arsenic level 0.013mg/kg, treated with three different concentrations of Arsenic 0.02 mg/l, 0.06mg/l and 0.08mg/l showed marked changes in the physiology of test sample in the retention period of 30 days. Percent germination was recorded as 16.6% in the soil containing 0.08mg/l. Synthesis of chlorophyll a and chlorophyll b was recorded on 5th, 15th and 30th day. It was estimated highest 44.343 mg and 17.837 mg in the sample plant grown at the lowest concentration of Arsenic (0.02 mg/l) in the soil. Significantly, this research work addresses the physiological aspect and the results provide scientific understanding of this research area of Arsenic toxicity in soil plant systems.

Seed germination ecology of meadow knapweed (Centaurea × moncktonii) populations in New York State, USA

The introduced meadow knapweed (Centaurea × moncktonii C.E. Britton), a hybrid of black (Centaurea nigra L.) and brown (Centaurea jacea L.) knapweeds, is increasingly common in pastures, meadows, and waste areas across many U.S. states, including New York. We evaluated the effects of temperature, light, seed stratification, scarification, and population on percent germination in four experiments over 2 yr. Percent germination ranged from 3% to 100% across treatment combinations. Higher temperatures (30:20, 25:15, and sometimes 20:10 C day:night regimes compared with 15:5 C) promoted germination, especially when combined with the stimulatory effect of light (14:10 h L:D compared with continuous darkness). Under the three lowest temperature treatments, light increased percent germination by 15% to 86%. Cold-wet seed stratification also increased germination rates, especially at lower germination temperatures, but was not a prerequisite for germination. Scarification did not increase percent germination. Differences between C. × moncktonii populations were generally less significant than differences between temperature, light, and stratification treatments. Taken together, these results indicate that C. × moncktonii is capable of germinating under a broad range of environments, which may have facilitated this species’ range expansion in recent decades. However, C. × moncktonii also shows evidence of germination polymorphism: some seeds will germinate under suboptimal conditions, while others may remain dormant until the abiotic environment improves. Subtle differences in dormancy mechanisms and their relative frequencies may affect phenological traits like the timing of seedling emergence and ultimately shape the sizes and ranges of C. × moncktonii populations.

Sorghum Seed Fungal Community and Their Association with Grain Mold Severity, Seed Weight, and Germination Rate

Grain mold, considered the most important disease of sorghum, is associated with several fungal genera. The disease reduces both yield and quality. In this study, over 300 sorghum seed samples collected from Texas, Florida, and Georgia were evaluated for grain mold severity, seed weight, germination rate, and seed fungal community. Grain mold severity of the seed samples, except for those collected from Cameron, Texas, were rated 3 or higher, indicating that these sorghum lines were moderately susceptible under naturally-infected field conditions during the 2016 and 2017 growing seasons. Seed weight across surveyed locations ranged from 1.1 g to 4.0g for samples collected in Texas during the same period. Percent germination rates for samples collected in Texas ranged from 59.6% to 86.7%. Sorghum samples collected from Florida and Georgia exhibited moderately susceptible response to grain mold infection. Mean seed weight was 1.9 g for samples collected from Florida, while in Georgia, mean seed weight was 2.3 g. Germination rate was low for samples collected from Florida and Georgia. Mycological analysis of sorghum seed samples collected from farmers’ fields in Central and South Texas during the 2016 and 2017 growing seasons showed Alternaria species as the most frequently isolated fungal genus, accounting for 40% and 42 % in 2016 and 2017, followed by Fusarium incarnatum, F. acuminatum, F. equiseti, & F. semitectum Complex. In Florida and Georgia, Fusarium incarnatum, F. acuminatum, F. equiseti, & F. semitectum Complex was the most frequently recovered fungal species, accounting for 77% and 72% of the total. genera/species isolated from seed samples. Other fungal species, including Curvularia lunata, Bipolaris sp., Colletotrichum sublineola, F. verticillioides, Penicillium sp., Aspergillus flavus, F. thapsinum, F. oxysporum, F. sporotrichioides, F. graminearum, F. proliferatum, and Aspergillus niger were also isolated from sorghum seeds in various frequencies. In conclusion, the presence of large number of fungal genera associated with grain deterioration and their effect on other traits, makes management of this disease complex challenging. To identify grain mold resistant sources in a region, using the most dominant species in that region to screen the sorghum germplasm is recommended.

Combined Effects of Vernalization and Gibberellic Acid on Quality Seed Production of Summer Onion (Allium cepa L.)

The purpose of the present study was to evaluate the effect of vernalization and GA3 on seed yield and reproductive quality of summer onion. There were three vernalization treatments viz., no vernalization (control), vernalization at 5°C for 14 days and vernalization at 10°C for 14 days and four GA3 treatment viz., 0, 50, 100 and 150 ppm. The two-factor experiment was conducted in the Randomized Complete Block Design (RCBD) with three replications. Combination between vernalization and GA3 was significant on the parameters such as plant height, number of leaves plant-1, the highest number of flowering stalk, number of umbels plant-1, number of bud umbel-1, percent flowering at 45 and 60 DAP, number of seeds umbel-1, weight of seeds umbel-1, weight of seeds plant-1, weight of seeds plot-1, 1000 seed weight, seed yield, number of fruits umbel-1, percent of fruit set umbel-1and percent germination. Combined effect of vernalization & GA3 was considered the highest seed yield (280.42 kgha-1) was obtained from vernalization at 5°C for 14 days with 100 ppm GA3. The lowest values of all the parameters were recorded in the control treatment. No limitation is found in the present experiment. Combined use of proper vernalization of mother bulb and suitable concentration of gibberellic acid can be one possible way to expand onion production during the summer.

The Influence of Colour and Thickness of Nylon Mulch on Soil Temperature, Moisture, Percent Germination and Some Growth Parameters of Cucumber (cucumis sativus L.) Seedlings

Heat, moisture and oxygen are important factors that has controlled seed germination, thus A 2 ×4 factorial greenhouse experiment was conducted to determine the influence of colour and thickness of nylon mulch on soil temperature, moisture, percent germination and selected growth indicators of cucumber (Cucumis sativus L.) seedlings in a completely randomized design (CRD), where the treatments; nylon colour (white and black) and thicknesses (0, 1.5, 3.0, and 4.5 mm) were replicated three times. The analysis of variance showed that the white nylon thickness had positive significant (P ≤ 0.05) influence on soil temperature, soil moisture, plant height and number of leaves, while black nylon thickness had positive significant (P ≤ 0.05) influence on soil moisture and plant height and a negative significant (P ≤ 0.01) influence on percent germination, it was also discovered that 1.5 mm thickness of the white nylon contributed significantly (p ≤ 0.05) to the parameters measured, therefore, white nylon of 1.5 mm thickness could be recommended as mulch material for cucumber production in a sandy clay soil.