scholarly journals Melatonin Alleviates Low-Temperature Stress via ABI5-Mediated Signals During Seed Germination in Rice (Oryza sativa L.)

2021 ◽  
Vol 12 ◽  
Author(s):  
Ruiqing Li ◽  
Meng Jiang ◽  
Yue Song ◽  
Huali Zhang

With increasing areas of direct sowing, low-temperature (LT) stress drastically affects global rice production. Exogenous applications of melatonin (MT) serve as one of the effective ways to improve seed germination under various stress conditions. In this study, we found that MT treatment greatly improved the LT stress-induced loss of germination percentage and the weak performance of seedlings under LT of constant 20°C (LT20). This was largely dependent on the activated antioxidant system and enhanced activities of storage substance utilization-associated enzymes. Moreover, we also detected that exogenous feeding of MT significantly increased the biosynthesis of gibberellin (GA) and endogenous MT but simultaneously inhibited the accumulation of abscisic acid (ABA) and hydrogen peroxide (H2O2) under LT20 stress. These results suggested that MT had antagonistic effects on ABA and H2O2. In addition, MT treatment also significantly enhanced the expression of CATALYSE 2 (OsCAT2), which was directly regulated by ABA-INSENSITIVE 5 (OsABI5), a core module of ABA-stressed signals, and thus promoting the H2O2 scavenging to reach reactive oxygen species (ROS) homeostasis, which consequently increased GA biosynthesis. However, in abi5 mutants, OsCAT2 failed in response to LT20 stress irrespective of MT treatment, indicating that OsABI5 is essential for MT-mediated seed germination under LT20 stress. Collectively, we now demonstrated that MT showed a synergistic interaction with an ABI5-mediated signal to mediate seed germination, partially through the direct regulation of OsCAT2.

2013 ◽  
Vol 5 (3) ◽  
pp. 325-331 ◽  
Author(s):  
Reyhaneh AZIMI ◽  
Hassan FEIZI ◽  
Mohammad KHAJEH HOSSEINI

The goal of this study was to evaluate concentrations of nanosized TiO2 at 0, 5, 20, 40, 60 and 80 mg L-1 with bulk TiO2 for possible stimulatory effects on wheatgrass seed germination and early growth stage. After 14 days of seed incubation, germination percentage improved by 9% following exposure to 5 ppm nanosized TiO2 treatment comparing to control. Similar positive effects occurred in terms of germination value and mean daily germination. Application of bulk TiO2 particles in 80 ppm concentration greatly decreased the majority of studied traits. Therefore phytotoxicity effect observed on wheatgrass seedling by application of bulk TiO2 particles in 80 ppm concentration. Exposure of wheatgrass seeds to 5 ppm nanosized TiO2 and bulk and nanosized TiO2 at 60 ppm obtained the lowest mean germination time but higher concentrations did not improve mean germination time. In general, there was a positive response by wheatgrass seed to some concentrations of nanosized TiO2. Usage of nanoparicles in order to improve germination and establishment of range plant in adverse environments similar to rangeland could be possible.


2021 ◽  
Vol 30 (2) ◽  
pp. 209-216
Author(s):  
O. J. Babayemi ◽  
I. O. Daniel ◽  
M. A. Bamikole ◽  
A. Ogungbesan ◽  
B. O. Oduguwa

Germination tests were conducted on the seeds of three species of Tephrosia (T. bracteolata, T. candida, and T. linearis) to investigate potential seedling establishment and possible pre-treatments to improve seed germination. Pre-culture treatments were: i) No treatment (control), ii) rubbed in sand paper, iii) soaking in boiled water for 30 seconds, iv) for 3 minutes, v) for 5 minutes, vi) soaking in concentrated sulphuric acid, and vii) soaking in water for 24 hours. After treatment, a total of two hundred and fifty seeds (5 replicates each of 50 seeds) were cultured on moist filter paper for 15 days. Cumulative percentage germination, percentage dormant seeds and germination rates were calculated. Seeds of all the species of Tephrosia exhibited innate dormancy at varying levels, but most pronounced in T. linearis. Soaking seeds in boiled water for 30 seconds to 5 minutes resulted in higher seed germination (p<0.05) than other pre-culture seed treatments in all the genotypes. Percentage hard seeds were also minimal in seeds treated this way, indicating effective dormancy alleviation in Tephrasia by these treatments. From the trial, soaking seeds in boiled water for 30 seconds is recommended as treatment of Tephrosia seeds to enhance germination and optimal potential seedling establishment.


2015 ◽  
Vol 2 (2) ◽  
pp. 118-122
Author(s):  
Kavitha D

Weeds are enemies to the crop plants and have harmful effects on agricultural crops due to several factors such as competition for space, light and nutrients and allelopathy. In the present study,various concentrations (0,5,10,15,20 and 25%) of whole plant aqueous extractsof weeds, Cyperus rotundusL.( Purple nut sedge) and Cynodan dactylon(L.) Pers. (Bermuda grass) were tested for assessing their allelopathic potential on seed germination and seedling growth of some rice (Oryza sativa L.) cultivars i.e.ADT-36,BPT5204 and IR-20 using pot culture experiments. The experimental results revealed that all the concentrations of both the weed extracts had inhibition on germination percentage, seedling length, number of,dry weight and chlorophyll contents of 15 day old seedlings of all the three rice cultivars and the inhibitory effect of the extracts was concentration dependent. However, at 5% of C. rotundus and10% of C. dactylon extracts did notaffect seed germination of IR-20 . Among the rice cultivars,the higher degree of growth inhibition was observed in ADT-36followed by BPT-5204 and IR-20 . The weed C.rotundusexhibited more intense on growth suppression of rice cultivars thanC.dactylon.


2018 ◽  
Vol 21 (2) ◽  
pp. 42-47 ◽  
Author(s):  
Mahmoud. A. Ghayyad

Abstract Seeds of Prunus species do not germinate as a result of different mechanisms of dormancy such as physiological, physical and/or chemical ones. This study was carried out in order to determine the effects of three concentrations of Gibberellic acid (GA3) 1, 3, and 5 mg.L−1 and low temperature at 5 °C on germination and on the length of isolated embryos from cotyledons of almond, apricot, plum, peach, mahaleb and sweet cherry on top of filter paper under laboratory conditions. The highest germination percentage (96.67%) was at 1 mg.L−1 GA3 without cold treatment or 3 mg.L−1 GA3 + cold treatment in almond, the highest length of embryos (15.47 mm) was also in almond at 1 mg.L−1 GA3 without cold treatment. Embryos of mahaleb and sweet cherry germinated at low germination percentages of 31.16%, 33.33% respectively at 3 mg.L−1 GA3 + cold treatment. It was concluded that embryos of almond, apricot, plum and peach were germinated successfully on top of filter paper under laboratory conditions and GA3 increased significantly the germination percentages of the isolated embryos either after cold treatment or without compared with controls. A strong positive correlation was found between seed germination without testa, embryos germination and final embryos length simultaneously.


2021 ◽  
Author(s):  
Phooi Chooi Lin ◽  
Elisa Azura Azman ◽  
Roslan Ismail

Abstract Basella rubra L. is a type of spinach, which is edible with high nutrient composition. It is also known to be an antioxidant. However, initial germination and root growth remain an issue due to hard exterior seed coating. Thus, some may germinate within 10 to 21 days, and some may not work at all. Inhibited growth may lead to vegetative propagation and micropropagation, which fundamentally reduce the growth and yield. Basella seed treated with Bokashi leachate was found to improve seed germination and root growth. A study was conducted using food waste EM Bokashi leachate (0:1, 1:1500, 1:1000, 1:500) with biopriming duration (6 and 12 hours). The experiment was conducted in a completely random design (CRD) with 3 replications of 100 seeds, with 24 experimental units. Based on the results, a short biopriming duration (6 hours) significantly enhanced the mean germination rate, germination speed accumulated, and coefficient of germination velocity. However, germination percentage had no significant improvement by leachate. Long priming duration significantly reduced the root development due to the seed may loss of desiccation tolerance. The concentration of leachate and priming duration had no significant interaction. In order to improve the germination and root growth performance, 6 hours of seeds priming duration or 1:500 (0.2%) of food waste Bokashi leachate was recommended to soak the Basella rubra seeds.


Author(s):  
M. Ananthi ◽  
P. Selvaraju ◽  
K. Sundaralingam

Laboratory experiment was carried out using ‘PKM 1’ chilli (Capsicum annuum L.) seed to standardize bioprimed seeds under moisture stress condition inorder to improve seed germination and seedling vigour. To induce the moisture stress, optimize the different concentration of water holdings capacity viz., 80, 60, 40 and 20% were used for best bioprimed seed treatment (biocontrol agents (Pseudomonas fluorescens 60% 12 h, Trichoderma viride 60% 9 h) and liquid biofertilizers (Azospirillum 10% 9 h and Phosphobacteria 15% 9h )) along with hydroprimed seed and control seed. Seed bioprimed with Pseudomonas fluorescens 60% for 12 h improved the germination percentage ( 82), root length (14.2 cm), shoot length (6.2 cm), dry matter production (0.0489 g 10 seedlings-1) and vigour index (1673) compared to control seed. Seed biopriming with  Pseudomonas fluorescens 60% for 12 h can be adopted to improve seed germination and seedling vigour under moisture stress condition upto 20%.


Author(s):  
SAMIR A SEIF EL-YAZAL ◽  
MOHAMED A EI-YAZAL

Objective: Freshly harvested seeds of “Local” apricot variety were found to be dormant and did not germinate at all. A specific low-temperature stratification treatment was required to overcome seed dormancy. The most effective temperature for breaking seed dormancy, germination, and seedling growth was 5°C cold stratification (CS). Increased seed germination percentage was recorded when the period of stratification prolonged. Seedling developed from stratified seeds had better growth than those developed from non-stratified seeds. Methods: For stratification treatments, the seeds with removed endocarp were mixed with moistened sand. Afterward, they were subjected to a period of stratification at 5°C. Seeds were stratified in pots of 30 cm×40 cm. Stratified seeds were regularly irrigated once per week. To prevent the water loss during stratification upper surface of pots was covered by a sack. The following stratification was applied for apricot variety: CS for 0, 3, 6, 9, 12, and15 days in 1998 and 1999 years for “Local” variety. Results: Apricot seeds required a CS of about 15 days for “Local” variety to reach maximum germination and normal seedling growth. Moreover, when stratification period was prolonged, some of the chemical constituents of apricot seeds were increased and other was decreased. Therefore, it can be suggested that breaking of dormancy is coincided with several changes in different chemical constituents of seeds. Some of these materials increased (total, reducing and non-reducing sugars, total free amino acids, total indoles, and total and conjugated phenols) and other materials such as free phenols which decreased at seed germinations. Conclusion: The most effective temperature for breaking seed dormancy, germination, and seedling growth was 5°C CS. Increased seed germination percentage was recorded when the period of stratification prolonged. Seedling developed from stratified seeds had better growth than those developed from non-stratified seeds.


2019 ◽  
Vol 32 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Luma Rayane de Lima Nunes ◽  
Paloma Rayane Pinheiro ◽  
Charles Lobo Pinheiro ◽  
Kelly Andressa Peres Lima ◽  
Alek Sandro Dutra

ABSTRACT Salinity is prejudicial to plant development, causing different types of damage to species, or even between genotypes of the same species, with the effects being aggravated when combined with other types of stress, such as heat stress. The aim of this study was to evaluate the tolerance of cowpea genotypes (Vigna unguiculata L. Walp.) to salt stress at different temperatures. Seeds of the Pujante, Epace 10 and Marataoã genotypes were placed on paper rolls (Germitest®) moistened with different salt concentrations of 0.0 (control), 1.5, 3.0, 4.5 and 6.0 dS m-1, and placed in a germination chamber (BOD) at temperatures of 20, 25, 30 and 35°C. The experiment was conducted in a completely randomised design, in a 3 × 4 × 5 scheme of subdivided plots, with four replications per treatment. The variables under analysis were germination percentage, first germination count, shoot and root length, and total seedling dry weight. At temperatures of 30 and 35°C, increases in the salt concentration were more damaging to germination in the Epace 10 and Pujante genotypes, while for the Marataoã genotype, damage occurred at the temperature of 20°C. At 25°C, germination and vigour in the genotypes were higher, with the Pujante genotype proving to be more tolerant to salt stress, whereas Epace 10 and Marataoã were more tolerant to high temperatures. Germination in the cowpea genotypes was more sensitive to salt stress when subjected to heat stress caused by the low temperature of 20°C or high temperature of 35°C.


Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 338
Author(s):  
Naeem Ahmed ◽  
Asad Masood ◽  
Kim S. Siow ◽  
M. F. Mohd Razip Wee ◽  
Rahmat Zaki Auliya ◽  
...  

In general, seed germination is improved by low-pressure plasma (LPP) treatment using precursors such as air, nitrogen, argon, or water (H2O). Here, H2O-based LPP treatment using the optimized parameters of 10 W and 10 s improves the germination of Bambara groundnut seeds by 22%. LPP increases the wettability and roughness of the seed hilum while oxidizing the surface with carboxyl and amine groups. In this H2O-based treatment of Bambara groundnut seeds, combinatory etching and chemical modification facilitated the imbibition process and increased the germination percentage. The success of this method has the potential to be scaled up to solve food security with seeds otherwise facing germination-related issues.


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