Hormonal nature of seed responses to fluctuating temperatures in <i>Cynara cardunculus</i> (L.)

Huarte, Héctor Roberto; Benech‐Arnold, Roberto L.

doi:10.1017/s0960258509990249

Cited by 39 publications

(43 citation statements)

References 36 publications

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“…Huarte and Benech-Arnold (2010) found that exogenous GA 3 could entirely substitute for temperature fluctuation for C. cardunculus seed germination. This suggests that temperature fluctuation may increase GA biosynthesis during imbibition and increase embryo growth potential to overcome physical constraint.…”

Section: Seed Germination and Dormancy Response To Temperaturementioning

confidence: 98%

“…Many studies (Chen et al 2009;Baskin and Baskin 2004) have shown that ABA is one of the most important inhibitors of seed germination. Huarte and Benech-Arnold (2010) reported that fluctuating temperature significantly reduced embryo sensitivity to ABA, and possible contributed to dormancy release. Results of the present study showed that an ABA inhibitor, fluridone, significantly increased seed germination at 20/30°C, suggesting that ABA biosynthesis during imbibition play a critical role in seed dormancy maintenance (Baskin and Baskin 2004).…”

Section: Seed Germination and Dormancy Response To Temperaturementioning

confidence: 99%

“…This phenomenon has important ecological significance associated with the strategies of seed to detect canopy gaps, depth of burial in soil or position under water (Fenner and Thompson 2005). While seed responses to fluctuating temperature are widespread among many species, the physiological and biochemical mechanisms underlying such responses are still largely unknown (Huarte and Benech-Arnold 2010).…”

Section: Introductionmentioning

confidence: 99%

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Hormonal and temperature regulation of seed dormancy and germination in Leymus chinensis

Huang

Wang

2012

Plant Growth Regul

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Fluctuating temperature plays a critical role in determining the timing of seed germination in many plant species. However, the physiological and biochemical mechanisms underlying such a response have been paid little attention. The present study investigated the effect of plant growth regulators and cold stratification in regulating Leymus chinensis seed germination and dormancy response to temperature. Results showed that seed germination was less than 2 % at all constant temperatures while fluctuating temperature significantly increased germination percentage. The highest germination was 71 % at 20/30°C. Removal of the embryo enclosing material of L. chinensis seed germinated to 74 %, and replaced the requirement for fluctuating temperature to germinate, by increasing embryo growth potential. Applications of GA 4?7 significantly increased seed germination at constant temperature. Also, inhibition of GA biosynthesis significantly decreased seed germination at fluctuating temperatures depending upon paclobutrazol concentration. This implied GA was necessary for non-dormant seed germination and played an important role in regulating seed germination response to temperature. Inhibition of ABA biosynthesis during imbibition completely released seed dormancy at 20/30°C, but showed no effect on seed germination at constant temperature, suggesting ABA biosynthesis was important for seed dormancy maintenance but may not involve in seed germination response to temperature. Cold stratification with water or GA 3 induced seed into secondary dormancy, but this effect was reversed by exogenous FL, suggesting ABA biosynthesis during cold stratification was involved in secondary dormancy. Also, cold stratification with FL entirely replaced the requirement of fluctuating temperature for germination with seeds having 73 % germination at constant temperature. This appears to be attributed to inhibition of ABA biosynthesis and an increase of GA biosynthesis during cold stratification, leading to an increased embryo growth potential. We suggest that fluctuating temperature promotes seed germination by increasing embryo growth potential, mainly attributed to GA biosynthesis during imbibitions. ABA is important for seed dormancy maintenance and induction but showed less effect on non-dormant seed germination response to temperature.

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Section: Seed Germination and Dormancy Response To Temperaturementioning

confidence: 98%

Section: Seed Germination and Dormancy Response To Temperaturementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hormonal and temperature regulation of seed dormancy and germination in Leymus chinensis

Huang

Wang

2012

Plant Growth Regul

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“…We combined germination data from the range of experimental Ψ treatments and used equation 2 to predict and plot germination [34]. Following Huarte and Benech-Arnold [35], we used the Solver tool of Microsoft Excel (2003–2010) to derive parameters for this function by minimizing the root-mean-square error (RMSE) between simulated and observed data. ANOVA was conducted for each parameter and protected LSD (P<0.05) values obtained using JMP 8.0 software (SAS Institute Inc. Cary, NC); orthogonal contrasts of means were subsequently used to compare between R and S groups of populations.…”

Section: Methodsmentioning

confidence: 99%

Stratification Requirements for Seed Dormancy Alleviation in a Wetland Weed

2013

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Echinochloaoryzicola(syn.E. phyllopogon) is an exotic weed of California rice paddies that has evolved resistance to multiple herbicides. Elimination of seedlingsthroughcertain weed control methods can limit the spread of this weed, but is contingent on accurate predictions of germination and emergence timing, which are influenced by seed dormancy levels.In summer annuals, dormancy can often be relieved through stratification, a period of prolonged exposure to cold and moist conditions.We used population-based threshold models to quantify the effects of stratification on seed germination of four E. Oryzicola populations at a range of water potential (Ψ) and oxygen levels. We also determined how stratification temperatures, moisture levels and durations contributed to dormancy release. Stratification released dormancy by decreasing base Ψ and hydrotimerequired for germination and by eliminating any germination sensitivity to oxygen. Stratification also increased average germination rates (GR), which were used as a proxy for relative dormancy levels. Alternating temperatures nearly doubled GR in all populations, indicating that seeds could be partially dormant despite achieving high final germination percentages. Stratification at Ψ = 0 MPa increased GR compared to stratification at lower water potentials, demonstrating that Ψ contributed to regulating dormancy release. Maximum GR occurred after 2-4 weeks of stratification at 0 MPa; GR were often more rapid for herbicide-resistant than for herbicide-susceptible seeds, implying greater dormancy in the latter. Manipulation of field conditions to promote dormancy alleviation of E. oryzicola seeds might improve the rate and uniformity of germination for seed bank depletion through seedling weed control. Our results suggest field soil saturation in winter would contribute towards E. oryzicola dormancy release and decrease the time to seedling emergence.

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“…sylvestris seeds display an almost absolute requirement for fluctuating temperatures for dormancy termination. Indeed, studies in C. cardunculus (L.) have shown that fluctuating temperatures terminate dormancy by reducing ABA content and sensitivity (Huarte and Benech-Arnold, 2010). This implies that fluctuating temperatures terminate dormancy in this species through an enhancement of embryo potential to overcome a physical restraint for germination.…”

Section: Introductionmentioning

confidence: 99%

Fluctuating temperatures terminate dormancy inCynara cardunculusseeds by turning off ABA synthesis and reducing ABA signalling, but not stimulating GA synthesis or signalling

et al. 2014

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Fluctuating temperatures terminate seed dormancy in many species, including Cynara cardunculus (L.) var. sylvestris. Termination of physiological dormancy requires low ratios of abscisic acid (ABA)/gibberellins (GA). In a previous paper we have shown that physiological responses to fluctuating temperatures comprise a reduction of abscisic acid (ABA) content and sensitivity. However, a possible stimulation of GA synthesis was also suggested as part of the mechanism. That possible stimulation, as well as the identification of potential regulatory sites for ABA and GA metabolism and signalling involved in the termination of dormancy by fluctuating temperatures, are yet to be determined. In this study, we measured GA content and sensitivity in seeds incubated under constant and fluctuating temperatures. We also assessed the expression of several genes involved in ABA and GA metabolism and signalling. Our results show that fluctuating temperatures reduce ABA/GA ratios through a reduction in ABA accumulation during incubation but without altering GA synthesis as compared to that observed under constant temperatures. On the other hand, fluctuating temperatures did not increase sensitivity to GA. Fluctuating temperatures reduced the expression of CycaNCED and CycaABI5 (ABA synthesis and signalling genes) with a temporal pattern that coincides with the interruption of ABA accumulation that precedes germination of seeds incubated under fluctuating temperatures.However, fluctuating temperatures did not modify the expression of CycaCYP707A2 (ABA inactivation) as compared to that observed under constant temperatures. Consistent with our determinations of GA content and sensitivity, fluctuating temperatures did not modify the expression of GA synthesis (CycaGA3ox) and signalling genes (CycaRGL2 and CycaGAI) in relation to that observed at constant temperatures. These results show that fluctuating temperatures terminate dormancy in Cynara cardunculus seeds through an interruption in ABA accumulation and a reduction in ABA signalling exerted at the level of CycaNCED and CycaABI5 expression.

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Hormonal nature of seed responses to fluctuating temperatures in Cynara cardunculus (L.)

Cited by 39 publications

References 36 publications

Hormonal and temperature regulation of seed dormancy and germination in Leymus chinensis

Hormonal and temperature regulation of seed dormancy and germination in Leymus chinensis

Stratification Requirements for Seed Dormancy Alleviation in a Wetland Weed

Fluctuating temperatures terminate dormancy inCynara cardunculusseeds by turning off ABA synthesis and reducing ABA signalling, but not stimulating GA synthesis or signalling

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