scholarly journals The physiology of extremely desiccated Brassica juncea (L) seeds

2013 ◽  
Vol 46 (2) ◽  
pp. 5-13
Author(s):  
Savita Khattra ◽  
Kiranjyoti Sharma ◽  
Gurmit Singh

Seeds of four raya cvs., viz. RL 1359, RLM 198, RLM 619 and RLM 514 were desiccated for 2, 7, 15 and 45 days wchich led to different levels of seed moisture. Data on germination capacity speed of germination, seedling dry weight, electrical conductance, dehydrogenase activity and seed storage behaviour for up to two years after desiccation were recorded. Based on this data, cvs. RL 1359 and RLM 514 were found to be tolerant to desiccation 10 as low as 0.73 and 1.16 per cent seed moisture levels, respectively. Seeds of RLM 198 tolerated desiccation up to 2.28 per cent seed moisture. However, RLM 619 seeds showed desiccation injuries in seedling dry weight, electrical conductance and speed of germination at moisture levels below 5.67 per cent.

2013 ◽  
Vol 52 (1-2) ◽  
pp. 121-137 ◽  
Author(s):  
G. Singh ◽  
S. S. Gill ◽  
Kamaljit K. Sandhu

Seeds of muskmelon (<em>Cucuniis melo</em>) cultivars viz Pb. Hybrid and Pb. Sunehri were osmoconditioned with Polyethylene glycol (PEG) and KNO<sub>3</sub> solutions to enhance their performance at low temperature. Osmoconditioning both with PEG 6000 and KNO<sub>3</sub> increased per cent germination, speed of germination, vigour in terms of dry weight and length of the seedlings and root/shoot ratios. KNO<sub>3</sub> priming recorded more pronounced effects in all the above mentioned parameters. Other vigour parameters such as electrical conductance of seed leachates was decreased with osmoconditioning whi]e dehydrogenase activity was enhanced. Osmoconditioning resulted in increased activity of amylases.


Author(s):  
K. D. Sommerville ◽  
G. Errington ◽  
Z-J. Newby ◽  
G. S. Liyanage ◽  
C. A. Offord

AbstractSeed banking of rainforest species is hindered by lack of knowledge as to which species are tolerant of desiccation and freezing. We assessed 313 Australian rainforest species for seed banking suitability by comparing the germination percentage of fresh seeds to seeds dried at 15% RH and seeds stored at −20 °C after drying. We then compared desiccation responses to environmental, habit, fruit and seed characteristics to identify the most useful predictors of desiccation sensitivity. Of 162 species with ≥ 50% initial germination, 22% were sensitive to desiccation, 64% were tolerant and 10% were partially tolerant; the responses of 4% were uncertain. Of 107 desiccation tolerant species tested for response to freezing, 24% were freezing sensitive or short-lived in storage at −20 °C. Median values for fresh seed moisture content (SMC), oven dry weight (DW) and the likelihood of desiccation sensitivity (PD-S) were significantly greater for desiccation sensitive than desiccation tolerant seeds. Ninety-four to 97% of seeds with SMC < 29%, DW < 20 mg or PD-S < 0.01 were desiccation tolerant. Ordinal logistic regression of desiccation response against environmental, habit, fruit and seed characteristics indicated that the likelihood of desiccation sensitivity was significantly increased by a tree habit, fleshy fruit, increasing fresh SMC and increasing PD-S. The responses observed in this study were combined with earlier studies to develop a simple decision key to aid prediction of desiccation responses in untested rainforest species.


1995 ◽  
Vol 22 (1) ◽  
pp. 22-26 ◽  
Author(s):  
J. F. Spears ◽  
G. A. Sullivan

Abstract Classification of peanuts (Arachis hypogaea L.) based on pod mesocarp color has become a popular means of estimating maturity of runner peanuts. This study was initiated to determine if the hull mesocarp color is related to seed maturity of virginia-type peanuts and to evaluate changes in quality as seed mature. Cultivars NC 7 and NC 9 peanuts were harvested by hand in 1990, 1991, and 1992. Pods were separated according to mesocarp color. Seed moisture content and dry weight within a maturity class varied with cultivar and production year. Germination of NC 7 seed grown in 1990 and 1992 increased as seed approached maturity. Immature NC 9 seed grown in 1991 and 1992 had substantially lower germination than seed from mature pods. There was no increase in germination during maturation of NC 7 seed harvested in 1991 or NC 9 from 1990. Seed leakage during imbibition, measured by electrical conductivity, decreased as seed matured. The lowest leakage levels occurred when seed had reached physiological maturity. Germination following accelerated aging (AA) increased as seed matured. Maximum AA germination of NC 7 occurred when seed had reached 77, 84, and 100% of their final dry weight in 1990, 1991, and 1992, respectively. NC 9 seed achieved maximum germination following AA after the seed amassed at least 90% of their final dry weight.


2018 ◽  
Vol 15 (2) ◽  
pp. 177-192
Author(s):  
RR Saha ◽  
A Hannan ◽  
A Nessa ◽  
MA Malek ◽  
MR Islam

An experiment on hundred wheat genotypes under different levels of osmotic stress was carried out during 2014 to select the genotype(s) tolerant to drought at germination and early seedling stage. Different levels of osmotic stress were imposed by using polyethylene glycol (PEG). Three osmotic stress levels viz. control (distilled water), 15% PEG solution and 25% PEG solution were used. Among the 100 genotypes the rate of germination percentage, final germination (%), root and shoot dry weight, amount of respiration and vigour index under PEG treatment was found significantly lower than that of control condition. Compared to control condition relative decrease in rate of germination, final germination, amount of respiration and vigour index among the wheat genotypes were found more at 25% PEG than that of 15% PEG treatment. However, the seed metabolic efficiency was significantly higher in wheat genotypes under both 15% PEG and 25% PEG treatment compared to the control condition. A significant positive correlation exists between the important growth parameters like rate of germination (%), final germination (%), shoot dry weight, root dry weight and vigour index. On the basis of these physiological traits against osmotic stress, nine genotypes of wheat such as BD-480, BD-498, BD- 501, BD-513, BD-514, BD-519, BD-592, BD-618 and BD- 633 were selected as drought tolerant.SAARC J. Agri., 15(2): 177-192 (2017)


2007 ◽  
Vol 47 (6) ◽  
pp. 683 ◽  
Author(s):  
Pippa J. Michael ◽  
Kathryn J. Steadman ◽  
Julie A. Plummer

Seed development was examined in Malva parviflora. The first flower opened 51 days after germination; flowers were tagged on the day that they opened and monitored for 33 days. Seeds were collected at 12 stages during this period and used to determine moisture content, germination of fresh seeds and desiccation tolerance (seeds dried to 10% moisture content followed by germination testing). Seed moisture content decreased as seeds developed, whereas fresh (max. 296 mg) and dry weight (max. 212 mg) increased to peak at 12–15 and ~21 days after flowering (DAF), respectively. Therefore, physiological maturity occurred at 21 DAF, when seed moisture content was 16–21%. Seeds were capable of germinating early in development, reaching a maximum of 63% at 9 DAF, but germination declined as development continued, presumably due to the imposition of physiological dormancy. Physical dormancy developed at or after physiological maturity, once seed moisture content declined below 20%. Seeds were able to tolerate desiccation from 18 DAF; desiccation hastened development of physical dormancy and improved germination. These results provide important information regarding M. parviflora seed development, which will ultimately improve weed control techniques aimed at preventing seed set and further additions to the seed bank.


1965 ◽  
Vol 18 (3) ◽  
pp. 671 ◽  
Author(s):  
PJ Reis

The sulphur content of wool was measured during experiments in which the nutritive status of sheep was altered by changes in the amount or composition of the diet. Three experiments were carried out, involving 13 sheep and five diets given at different levels of feeding. Wool grown on delineated areas was collected and its clean dry weight and sulphur content were determined. Wool growth rates varied between 0�3 and 1� 8 mg clean dry wool/cm2/day.


2021 ◽  
Vol 38 (1) ◽  
pp. 144-157
Author(s):  
Thaísa De Oliveira Silveira ◽  
Madelon Rodrigues Braz ◽  
Gilmara Pires de Moura Palermo ◽  
Tiago Böer Breier

Seeds of native forest species for food and seedling production have a growing demand that impacts the need for studies involving seed storage in order to maintain good levels of germination quality. Thus, scientific analyzes that explore the physiological potential of the seeds of these species are necessary, especially for the pink pepper (Schinus terebinthifolia Raddi.), a species used as an alternative source of income for traditional communities and which has been arousing interest due to the consumption of its fruits as a condiment in the national and international market. This work aimed to assess the physiological quality of pink pepper seeds according to the storage period and seed size. The seeds came from a rural settlement, a pioneer in the extraction of pink pepper, in the state of Rio de Janeiro, Brazil. The seeds were evaluated for moisture content, germination, first count, length and dry weight of the germinated seedlings, during the period of time that they remained stored and the size of the seeds. The results allowed to conclude that: i) the germinative percentage of the stored pink pepper seeds decreased over the months; ii) the moisture content of the seeds decreased over the months evaluated iii) the different sizes of seeds did not show differences in germination and storage time and iv) values of length and dry weight of the seedlings did not differ according to the period of storage.


2020 ◽  
Vol 15 (3) ◽  
Author(s):  
Fatemeh Nejatzadeh-Barandozi

Ocimum basilicum L. is an herbaceous plant from the Labiate family that used fresh, as a spice, and as a medicinal plant. Mulch is technique capable of reducing evaporation from the surface of the soil in basil production systems; it has more impacts on yield and essential oil quality of a basil crop. This research was performed in order to study the effects of different mulch types and irrigation regimes on various growth parameters and the essential oil content of basil. Treatments included two mulch types (black plastic, wood chips, and control) and three irrigation levels (100, 80, and 60% of water requirements, calculated by evaporation pan class A), following a randomised complete block design with four replications. Results showed that the effect of irrigation on fresh weight, dry weight, leaf relative water content, leaf area, and essential oil yield was significant (P<0.05). The effect of mulch on fresh weight, dry weight, leaf area, inter-node distance, number of branches, and essential oil yield was significant (P<0.05). Interaction between irrigation and mulch on inter-node distance, fresh weight, dry weight, and leaf area was significant (P<0.05). This study identified wood chips as the best mulch treatment. The highest dry weight yield (38.35 g/plant) and the highest essential oil yield (82.83 L/ha) resulted when wood chip mulch was used in combination with irrigation at 100% of the water requirement. This combination also resulted in the highest water productivity in basil production.   Highlights - Different levels of irrigation alone did not always increase plant growth and yield of basil. - Different levels of mulch alone did not always increase plant growth and yield of basil. - Different levels of irrigation and mulch in combination used, increased, growth and essential oil yield of basil. - This study identified wood chips as the best mulch treatment. - The highest essential oil yield resulted with wood chip mulch and irrigation at 100% of the water requirement.


Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 904 ◽  
Author(s):  
Zhong-Wei Zhang ◽  
Yi-Ying Dong ◽  
Ling-Yang Feng ◽  
Zong-Lin Deng ◽  
Qiang Xu ◽  
...  

Oilseed rape (Brassica napus) is a Cadmium (Cd) hyperaccumulator. However, high-level Cd at the early seedling stage seriously arrests the growth of rape, which limits its applications. Brassica juncea had higher Cd accumulation capacity, but its biomass was lower, also limiting its applications. Previous studies have confirmed that Selenium (Se) can alleviate Cd toxicity. However, the regulatory mechanism of Se in different valence states of Cd accumulation was unclear. In this study, we investigated the ameliorating effects of three Se valence states, Na2SeO4 [Se(VI)], Na2SeO3 [Se(IV)] and Se-Met [Se(II)], to Cd toxicity by physiological and biochemical approaches in hydroponically-cultured Brassica juncea and Brassica napus seedlings. Although Se treatments slightly inhibited seedling Cd concentration, it tripled or quadrupled the Cd accumulation level per plant, because dry weight increased about four times more with Se and Cd application than with Cd treatment alone. Among the different valence states of Se, Se(II) had the most marked effect on reducing Cd toxicity as evidenced by decreased growth inhibition and Cd content. The application of Se(II) was effective in reducing Cd-induced reactive oxygen species accumulation, and promoted the antioxidant enzyme activity and photosynthesis of both Brassica species. In addition, Se(II) treatment increased the concentrations of Cd in the cell wall and soluble fractions, but the Cd concentration in the organelle part was reduced.


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