Modelling the effects of water stress and temperature on germination rate of Orobanche aegyptiaca seeds

Kebreab, E.; Murdoch, A. J.

doi:10.1093/jxb/50.334.655

Cited by 102 publications

(105 citation statements)

References 9 publications

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“…However, almost all previous applications of hydrotime and hydrothermal time assumed a normal distribution for w b(g) (using probit analysis; Bradford and Still 2004;Meyer and Allen 2009). The HTT model assumes the timing, rate, and percentage of seed germination for a constant temperature to be controlled by the difference between w of the seedbed and the w b for a given percentile (Kebreab and Murdoch 1999;Alvarado and Bradford 2002;Rowse and FinchSavage 2003). One of the advantages of this assumption is that the parameters rw b and mean w b(g) , along with h HT and T b , provide a complete description of the likely germination behavior of a seed population and allow for germination behavior of different species to be compared (Köchy and Tielbörger 2007).…”

Section: Discussionmentioning

confidence: 99%

Application of a Hydrothermal Time Seed Germination Model Using the Weibull Distribution to Describe Base Water Potential in Zucchini (Cucurbita pepo L.)

Atashi

Bakhshandeh

Mehdipour

et al. 2014

J Plant Growth Regul

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Seed germination has been modeled extensively using hydrothermal time (HTT) models. Generally, a normal distribution for base water potential w b(g) and a linear upward shift in w b(g) with increasing temperature were used within these models to relate variation in w b(g) to the variation in time to germination of a given fraction of seeds. However, little research has tested these assumptions. Therefore, the main purpose of this study was to test the assumption of normality in the distribution of w b(g) by germinating zucchini (Cucurbita pepo L.) seed with nondormant seed across a range of constant w at sub-and supra-optimal temperatures. Zucchini seeds were incubated at six constant temperature regimes (15, 20, 25, 30, 35, and 37°C) at each of the following osmotic potentials (0, -0.15, -0.30, -0.45, and -0.60 MPa). Results indicate that when incorporated into an HTT model, the Weibull distribution (R 2 = 0.85; RMSE = 11.89) more accurately described w b(g) and germination course over sub-and supra-optimal temperatures than HTT based on a normal distribution (R 2 = 0.77; RMSE = 14.80). According to these models, base temperature and base water potential for the 50th percentile (w b(50) ) were estimated at 9.38°C for both models and -1.27 and -1.31 MPa by the normal and Weibull distribution, respectively. Given the flexibility of the Weibull distribution this model not only provides a useful method for predicting germination but also a means for determining the distribution of w b(g) .

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Section: Discussionmentioning

confidence: 99%

Application of a Hydrothermal Time Seed Germination Model Using the Weibull Distribution to Describe Base Water Potential in Zucchini (Cucurbita pepo L.)

Atashi

Bakhshandeh

Mehdipour

et al. 2014

J Plant Growth Regul

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“…In all these cases, w b(g) values became more positive (i.e., increased) as T increased above T o . Moreover, other researchers indicated that at Ts [ T o , when T increases and approaches T c , the w b distribution shifts progressively towards and exceeds 0 MPa (Kebreab and Murdoch 1999). Bradford (2002) suggested that these changes in w b(g) might be responsible for delaying and inhibiting seed germination in the supra-optimal range of T.…”

Section: Introductionmentioning

confidence: 98%

“…To date, various mathematical models have been used, each with its strengths and weaknesses, to describe the relationship between germination rate (GR) and T (for example, Gummerson 1986;Kebreab and Murdoch 1999;Alvarado and Bradford 2002;Rowse and Finch-Savage 2003;Watt et al 2010Watt et al , 2011Bakhshandeh et al 2013;Atashi et al 2014a, b).…”

Section: Introductionmentioning

confidence: 99%

“…(Dahal and Bradford 1990), potato (Alvarado and Bradford 2002), carrot and onion (Rowse and Finch-Savage 2003) and zucchini (Atashi et al 2014a), as well as in weedy species, for example, Orobanche aegyptiaca (Kebreab and Murdoch 1999), Stellaria media L. (Grundy et al 2000), winterfat (Krascheninnikovia lanata (Pursh) A.D.J. Meeuse & Smit) (Wang 2005), Ambrosia trifida L. (Schutte et al 2008) and Bromus diandrus Roth (Garcia et al 2013).…”

Section: Introductionmentioning

confidence: 99%

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Hydrothermal time analysis of watermelon (Citrullus vulgaris cv. ‘Crimson sweet’) seed germination

et al. 2014

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Mavi K., 2010. The relationship between seed coat color and seed quality in watermelon Crimson sweet. Hort. Sci. (Prague), 37: 62-69. This work was carried out to determine the relationship between seed coat color and seed quality in Crimson sweet watermelon. Seed lots (1, 2, 3, and 4) were prepared taking into consideration seed coat colors in fresh seeds with naked eye. The color parameters of these prepared seed lots were determined using Minolta colorimeter. To determine quality differences between the seed lots, standard germination test, seed weight, water uptake ratio, mean germination time, emergence percentage, mean emergence time, seedling fresh weight, seedling dry weight and electrical conductivity values were determined. The seed weight (57.22 mg), germination percentage (86.5%), emergence percentage (77.5% total and 76.5% normal), seedling fresh weight (978.7 mg), and dry weight (64.7 mg) of the brown seed lot (Lot 1) were markedly higher than lots having lighter seed coat (2, 3, and 4). On the other hand the mean emergence time (7.7 days) and electrical conductivity value (128.8 µS/cm g in 24 h) of the brown seed lot (Lot 1) were lower than lots having lighter seed coat (2, 3, and 4). The obtained data indicated that seed quality differences can be determined according to the seed coat color of Crimson sweet seeds. It was found that seed lot 1 had higher seed vigor and viability than seed lots 2, 3, and 4. Color parameters b*, C*, L*, and H°, determined by Minolta colorimeter, showed significant correlation with seeds quality parameters.

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“…In nature, several environmental constraints, such as salinity (Kashem et al 2000), water stress (Kebreab and Murdoch 1999) and temperature (Welbaum et al 1998) can inhibit or reduce seed's ability to germinate. This stage is a major factor limiting the establishment of plants under saline conditions (Al-karaki 2001).…”

Section: Introductionmentioning

confidence: 99%

Effect of salinity on germination, phytase activity and phytate content in lettuce seedling

et al. 2010

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Seeds of four lettuce (Lactuca sativa L.) varieties (Romaine, Augusta, Vista and Verte) differing in their salt sensitivity were sown at 0 (Control), 50, 100 and 150 mM NaCl. The final germination percentage decreased with the increasing salinity and was annulated at the highest salt concentration in Vista and Verte, the most sensitive varieties. However, in the less sensitive ones, Romaine and Augusta, it was slightly modified at 50 and 100 mM NaCl and then decreased by 50% compared with the control, at 150 mM. The effects of NaCl 100 mM on seedling growth, phytase activities, phytate and inorganic phosphorus contents were studied in Romaine and Vista showing different behaviours towards salinity. Radicle and hypocotyl length and fresh and dry weights were reduced by salt treatment in both varieties. In addition, radicle phytase activity exhibited an increase in Romaine (less sensitive) and a decrease in Vista (more sensitive). In hypocotyl, this activity showed no difference with the control in the two varieties. However, in cotyledons, and during early hours after germination, salinity decreased phytase activity in both varieties whereas in the later hours (72-96 h) this activity reached the value of the control in Romaine. The enhancement of phytase activity was concomitant with an increase in orthophosphate content and a decrease in phytate reserve. These results suggest that salt presence in the medium delays Pi remobilization from phytate stock, but stimulates assimilation of phosphorus more than its accumulation in the organs of the two lettuce varieties.

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Modelling the effects of water stress and temperature on germination rate of Orobanche aegyptiaca seeds

Cited by 102 publications

References 9 publications

Application of a Hydrothermal Time Seed Germination Model Using the Weibull Distribution to Describe Base Water Potential in Zucchini (Cucurbita pepo L.)

Application of a Hydrothermal Time Seed Germination Model Using the Weibull Distribution to Describe Base Water Potential in Zucchini (Cucurbita pepo L.)

Hydrothermal time analysis of watermelon (Citrullus vulgaris cv. ‘Crimson sweet’) seed germination

Effect of salinity on germination, phytase activity and phytate content in lettuce seedling

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