scholarly journals Hydrotime model to evaluate the effects of a set of priming agents on seed germination of two leek cultivars under water stress

Author(s):  
Alessandro Romano ◽  
Romana Bravi

Water deficit is one of the main constraints of germination for many cultivated species. Among the techniques used to promote germination, seeds priming has been found to play a key role. In the present study, a set of different priming agents (KCl, KH2PO4, CaCl2 and PEG 8000) was tested on seeds of two leek (Allium ampeloprasum L.) cultivars (“Lungo della riviera” and “Monstrueux de Carentan”) to assess the effects on germination performances both in optimal hydration condition (Ψw = 0 MPa) and under water deficit (−0.3 and −0.6 MPa). Germination percentage of “Lungo della riviera” was improved by PEG and KCl at −0.3 MPa and −0.6 MPa, respectively, whereas CaCl2 improved germination of “Monstrueux de Carentan” at −0.6 MPa. Osmopriming was beneficial in terms of germination rate although to different extent depending on genotype and priming agent. The hydrotime model showed that the effects of priming on germination rate was mostly due to a lowering of the predicted hydrotime constant (θH), whereas median base water potential Ψb(50) tended to increase following treatments albeit with some exception. In this study, hydrotime model proved to be a useful tool to test the effectiveness of different priming treatments on leek seeds and the intraspecific variability in germination capability and speed under water stress.

Botany ◽  
2020 ◽  
Vol 98 (5) ◽  
pp. 283-291
Author(s):  
Samaneh Tatari ◽  
Farshid Ghaderi-Far ◽  
Ahad Yamchi ◽  
Asieh Siahmarguee ◽  
Ali Shayanfar ◽  
...  

Our aim was to determine whether the parameters of the hydrotime model can be used to compare the effects of seed priming treatments on germination. Seeds of three rapeseed cultivars (‘H61’, ‘H4815’, and ‘DK003’) were exposed to priming treatments and then their germination was tested at different water potentials. Seed priming improved the germination percentage, which was higher in ‘H4815’ than in the other two cultivars, and it increased germination rate (decreased θH) and uniformity (decreased σψb). The increase in germination rate was higher in PEG-osmoprimed than in NaCl-osmoprimed and hydroprimed seeds. The base water potential allowing 50% germination ([Formula: see text]) also was affected by seed priming, but the response of cultivars to different priming treatments varied. Compared with the control seeds, hydropriming of ‘H61’ seeds shifted ψb(50) toward negative values, whereas NaCl-osmopriming of ‘H4815’ seeds shifted ψb(50) toward negative values. On the other hand, priming of ‘DK003’ seeds shifted ψb(50) to more positive values and increased susceptibility to water stress. After dormancy-breaking and dormancy-induction treatments, ψb(50) shifted to more negative or positive values, indicating the release of primary dormancy and induction of dormancy, respectively. Therefore, priming treatments should be selected, depending on the environmental conditions anticipated to prevail during the germination of rapeseed seeds.


Author(s):  
Rong Li ◽  
Dandan Min ◽  
Lijun Chen ◽  
Chunyang Chen ◽  
Xiaowen Hu

This study determined the effects of priming on germination in response to temperature, water potential and NaCl. Thermal and hydrotime models were utilized to evaluate changes in parameters of the model after priming. Priming reduced the amount of thermal time in both cultivars, but slightly increased the base temperature for germination from 1.0 to 3.5°C in “Longdong”. Priming significantly increased germination rate at high water potential but had no effect at low water potential. Further, priming reduced the hydrotime constant but made the median base water potential value slightly more positive in both cultivars. Thus, priming increased germination rate in water but decrease it under severe water stress. Germination rate was significantly increased in both cultivars under salinity (NaCl) stress. Moreover, priming improved seedling growth in response to temperature, water and salinity stress in both cultivars.


2004 ◽  
Vol 34 (6) ◽  
pp. 1204-1209 ◽  
Author(s):  
Elisabetta Falleri ◽  
Claudine Muller ◽  
Elyane Laroppe

Beechnuts from two seedlots were pretreated, without medium, at a controlled moisture content (MC) of 30% before or after 1-year storage at –7 °C. Seeds treated with the two methods were germinated on substrates at decreasing osmotic potential down to –1.2 MPa. A moderate stress of –0.2 MPa caused a slight but significant decrease in germination percentage. Each further increment in water stress produced additional significant decreases in germination capacity. At –1.2 MPa, germination was almost prevented. Seeds pretreated before storage showed lower germination percentage and speed at all osmotic potentials, but this result was due to a marked effect of seed initial MC, rather than a lower resistance to water deficit. In fact, MC of beechnuts pretreated before storage was 8%, whereas beechnuts pretreated after storage started germination tests under water stress with an initial MC of 30%. Moreover, seeds at lower initial MC need more time to imbibe before the germination process can start. Seeds with higher initial MC were probably able to cope better with water deficit, at least during the 30-day germination test in the laboratory. A second experiment carried out on beechnuts treated only before storage but made to have different initial MC seemed to confirm this conclusion. Ungerminated seeds were not damaged, as revealed by a tetrazolium test performed at the end of each germination test. Advantages in nursery practice shown by dry, nondormant beechnuts (pretreated before storage) are discussed in relation to the possibility of sowing when water availability in the soil is not a limiting factor.


2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Shatha Abd Al-Hassan ◽  
Ahmed Ali Abdul Hadi Hassan

"A factorial experiment was carried out in the lab. college of Agricultural Engineering Science, University of Baghdad Al- Jadiriyah during year of 2017 With the aim of improving the germination properties of Maize variety of Noor under water stress. According to the Completely randomize design (CRD) with three replications were used in both and two factors: first: it included water tensile treatments by exposing the seeds to a solution of polyethylene glycol PEG 6000 with three levels (0, -4 ,-8) Bar, while the second factor with three concentrations of the compound peroxide Hydrogen H2O2 with a concentration of 50% (0, 10 , 20 mg L-1). The results showed that water stress had a significant effect on the characteristics of Maize seedlings, as it reduced the level of water stress (-8) bar, the average germination percentage, Average 80.00%, Root Shoot length, 7.900 , 5.22 (cm), respectively, seedling dry weight 269.9 (mg seedlings-1) and Seed vigor index of drought resistance 0.781,while treatment with compound hydrogen peroxide H2O2 contributed to improving the characteristics of Maize seedlings significantly, as the seed soaking treatment at a concentration of 20 (mg L-1) recorded the highest germination rate of 89.44%, the feather length of 5.90 (cm), and the seedling dry weight 353.6 (mg seedlings-1). Germination and vigor index of drought resistant 1.089. We recommend to soak maize seeds with peroxide Hydrogen H2O2 (10 ) mg L-1 for 24 h before planting, especially under water stress."


2007 ◽  
Vol 17 (4) ◽  
pp. 253-271 ◽  
Author(s):  
Alberto Gianinetti ◽  
Marc Alan Cohn

AbstractRed rice (Oryza sativaL.) dispersal units (florets) were dry-afterripened for 0–8 weeks and subsequently incubated at 30°C in polyethylene glycol (PEG) solutions with water potentials from 0 to − 1.6 MPa. Germination percentages and rates increased with dry-afterripening and water potential of the incubation medium. The seed population exhibited a normal distribution of base water potentials (Ψb, i.e. minimum water potential allowing germination) among individual seeds, characterized by three parameters: the hydrotime constant (θH), the mean base water potential (Ψb) and the standard deviation of the base water potential distribution (σΨb). Changes in germination during afterripening could be described by modifications of such parameters, particularlyΨb, which was employed to derive an index, DH(ARX = Ψb(ARX) − Ψb(ARN), where DH(ARX) represents a measure of dormancy of the seed population (in MPa) based on the hydrotime model,Ψb(ARX) is the mean base water potential of the seed population at any afterripening timeX, andΨb(ARN) is the mean water potential of the non-dormant (fully afterripened) population. The introduction of this index permitted interpretation of afterripening as a measurable reduction in the dormancy status of the seed, with progressive acquisition of both full germinative capacity and maximum germination rate, as anticipated by the hydrotime model. Moreover, secondary dormancy was induced proportionally to the reduction in water potential in the dark. Susceptibility to secondary dormancy induction was defined through DI(ARX), an index analogous to DH(ARX). These indices revealed that, in red rice, both breaking of primary dormancy and the inducibility of secondary dormancy followed decay kinetics with different sensitivities to the duration of dry storage.


2019 ◽  
Vol 29 (1) ◽  
pp. 12-20 ◽  
Author(s):  
Mohammad I. Abo Gamar ◽  
Mirwais M. Qaderi

AbstractWe examined the combined effects of temperature, carbon dioxide (CO2) and watering regime during seed maturation on subsequent germinability and total phenolics of Arabidopsis thaliana [wild-type (WT) and abi1-1 mutant] seeds. Mature seeds were collected from plants that were grown under lower (22/18°C, 16 h light and 8 h dark) or higher (28/24°C, 16 h light and 8 h dark) temperatures, at ambient (400 μmol mol–1) or elevated (700 μmol mol–1) CO2 concentration, and well-watered or water-stressed. Germinated and non-germinated (viable, rotten and empty) seed percentages, germination rate and total phenolics were determined for both genotypes. Higher maturation temperatures increased seed germination percentage, but decreased germination rate, percentage of rotten and non-germinated viable seeds, and total phenolics. Elevated CO2 increased seed total phenolics. Water stress decreased the percentage of non-germinated viable seeds. Neither of the two latter factors affected other measured parameters. Seeds of the abi1-1 mutant had higher total phenolics. The fate of seeds was mostly affected by higher temperatures and water stress. Also, seeds of the abi1-1 mutant had higher germination rate, empty seed percentage and total phenolics than seeds of the WT genotype. Germination percentage was highest for the WT seeds that matured on the water-stressed plants that were grown under higher temperatures at ambient CO2. It can be concluded that higher temperatures had highest effects on seed germinability and other parameters, and elevated CO2 did not alleviate the negative effects of higher temperatures on seed viability.


Weed Science ◽  
2020 ◽  
pp. 1-8
Author(s):  
Maor Matzrafi ◽  
O. Adewale Osipitan ◽  
Sara Ohadi ◽  
Mohsen B. Mesgaran

Abstract The environmental conditions under which parental plants are reared can affect the seed characteristics of the progeny. The variation originating from such maternal effects has rarely been incorporated into models of seed germination. Here, using Palmer amaranth (Amaranthus palmeri S. Watson), we examined the effects of water stress during the growth of parental plants on the progeny seed characteristics, including weight, size, final germination, and parameters of a hydrotime germination model. We grew two populations (from California and Kansas) under continuous water-deficit or well-watered conditions. In both A. palmeri populations, progeny seeds originating from water-stressed plants were heavier and larger than those from well-watered plants. Plants exposed to water stress also produced seeds that were ~30% less dormant than seeds from control plants. To test whether the maternal environment affects the parameters of a hydrotime model, progeny seeds were subject to five water potentials (0, −0.2, −0.4, −0.6, and −0.8 MPa) and incubated at 20 and 30 C; germination was monitored daily. The estimated median base water potential (Ψb(50)), that is, the water potential at which 50% of seeds cannot germinate, was consistently lower for seeds from water-stressed plants than for seeds from well-watered plants. Our results showed that A. palmeri plants experiencing drought during their growth produce seeds that are less dormant and can germinate from drier conditions—a maternal response that seems to be adaptive. These findings also call for development of germination models that incorporate the environmental conditions of both the current and past seasons to better describe the variability in germination of weed seeds.


2017 ◽  
Vol 9 (6) ◽  
pp. 154 ◽  
Author(s):  
Mlamuli M. Motsa ◽  
Cecilia Bester ◽  
Margaretha M. Slabbert ◽  
Mzabalazo Z. Ngwenya ◽  
Mardé Booyse

Cyclopia Vent. (honeybush) is a South African herbal tea legume endemic to the Cape Floristic Region of South Africa. At present, knowledge of reproductive fitness (fecundity) between cultivated and undomesticated Cyclopia species is scant. Cultivated genotypes of C. genistoides (L.) R.Br. and C. subternata Vogel were evaluated for their potential to produce fruit and seeds in different localities spanning two years. Fecundity and germination were also determined from natural environment of each species and compared to cultivated species in order to determine the variation between species and between cultivated and non-cultivated species. Seeds collected were weighed to determined seed mass and evaluated for germination rate and cumulative germination per individual site. A fifth of flowers developing into a pod, averaged more initiated and filled seeds per pod in C. subternata than C. genistoides. Germination percentage was directly proportional to rate of germination in both species. Cyclopia subternata had a higher fecundity and germination than C. genistoides in both cultivated and natural environments. The study results assist in the further improvement of the genus through breeding new cultivars for seed with desired qualities for improving commercial characteristics; planning of seed orchards for seed production, selecting of best sites, assisting in choosing progenies for seed production and rehabilitation of degraded sites for the sustainable production of honeybush.


2018 ◽  
Vol 51 (3) ◽  
pp. 51-68 ◽  
Author(s):  
M.K. Hasan ◽  
M.S. Islam ◽  
M.R. Islam ◽  
H.N. Ismaan ◽  
A. El Sabagh

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.


Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
M. Musse ◽  
G. Hajjar ◽  
N. Ali ◽  
B. Billiot ◽  
G. Joly ◽  
...  

Abstract Background Drought is a major consequence of global heating that has negative impacts on agriculture. Potato is a drought-sensitive crop; tuber growth and dry matter content may both be impacted. Moreover, water deficit can induce physiological disorders such as glassy tubers and internal rust spots. The response of potato plants to drought is complex and can be affected by cultivar type, climatic and soil conditions, and the point at which water stress occurs during growth. The characterization of adaptive responses in plants presents a major phenotyping challenge. There is therefore a demand for the development of non-invasive analytical techniques to improve phenotyping. Results This project aimed to take advantage of innovative approaches in MRI, phenotyping and molecular biology to evaluate the effects of water stress on potato plants during growth. Plants were cultivated in pots under different water conditions. A control group of plants were cultivated under optimal water uptake conditions. Other groups were cultivated under mild and severe water deficiency conditions (40 and 20% of field capacity, respectively) applied at different tuber growth phases (initiation, filling). Water stress was evaluated by monitoring soil water potential. Two fully-equipped imaging cabinets were set up to characterize plant morphology using high definition color cameras (top and side views) and to measure plant stress using RGB cameras. The response of potato plants to water stress depended on the intensity and duration of the stress. Three-dimensional morphological images of the underground organs of potato plants in pots were recorded using a 1.5 T MRI scanner. A significant difference in growth kinetics was observed at the early growth stages between the control and stressed plants. Quantitative PCR analysis was carried out at molecular level on the expression patterns of selected drought-responsive genes. Variations in stress levels were seen to modulate ABA and drought-responsive ABA-dependent and ABA-independent genes. Conclusions This methodology, when applied to the phenotyping of potato under water deficit conditions, provides a quantitative analysis of leaves and tubers properties at microstructural and molecular levels. The approaches thus developed could therefore be effective in the multi-scale characterization of plant response to water stress, from organ development to gene expression.


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