Reactive oxygen species, ABA and nitric oxide interactions on the germination of warm-season C4-grasses

Abstract

For non-dormant switchgrass seeds exhibiting diVerent levels of germination, treatment with H 2 O 2 resulted in rapid germination (<3 days) of all germinable seeds as compared to seeds placed on water. Exposure to 20 mM H 2 O 2 elicited simultaneous growth of the root and shoot system, resulting in more uniform seedling development. Seeds of big bluestem (Andropogon gerardii Vitman) and indiangrass [Sorghastrum nutans (L.) Nash] also responded positively to H 2 O 2 treatment, indicating the universality of the eVect of H 2 O 2 on seed germination in warm-season prairie grasses. For switchgrass seeds, abscisic acid (ABA) and the NADPH-oxidase inhibitor, diphenyleneiodonium (DPI) at 20 M retarded germination (radicle emergence), stunted root growth and partially inhibited NADPH-oxidase activity in seeds. H 2 O 2 reversed the inhibitory eVects of DPI and ABA on germination and coleoptile elongation, but did not overcome DPI inhibition of root elongation. Treatment with H 2 O 2 appeared to enhance endogenous production of nitric oxide, and a scavenger of nitric oxide abolished the peroxide-responsive stimulation of switchgrass seed germination. The activities and levels of several proteins changed earlier in seeds imbibed on H 2 O 2 as compared to seeds maintained on water or on ABA. These data demonstrate that seed germination of warm-season grasses is signiWcantly responsive to oxidative conditions and highlights the complex interplay between seed redox status, ABA, ROS and NO in this system.

Pretreatment with H2O2 in maize seeds: effects on germination and seedling acclimation to salt stress

“…As in our study, some authors have also observed increased germination of other species by soaking seeds in H 2 O 2 (Ching, 1959;Ogawa and Iwabuchi, 2001;Sarath et al, 2007). Ching (1959) showed that O 2 and H 2 O uptake is substantially increased in H 2 O 2 soaked Pseudotsuga menziesii seeds than in the control, suggesting an enhanced conversion rate of reserve lipids to carbohydrates and, consequently, increased synthesis of cellular components (Ching, 1959).…”

“…The first evidence of this effect was the stimulation of Pseudotsuga menziesii seed germination by soaking seeds in 1% H 2 O 2 (Ching, 1959). Similarly, H 2 O 2 seed germination stimulation was also obtained in Zinnia elegans (Ogawa and Iwabuchi, 2001), Panicum virgatum, Andropogon gerardii and Sorghastrum nutans (Sarath et al, 2007). Recently, the pretreatment of seeds with H 2 O 2 induced salt tolerance of wheat seedlings (Wahid et al, 2007).…”

The effect of H2O2 and abscisic acid (ABA) interaction on β-amylase activity under osmotic stress during grain development in barley

“…Furthermore, exogenous H 2 O 2 as a source of ROS, significantly promoted seed germination of barley and was able to reverse the inhibitory effects of ABA on germination of switch grass seeds, indicating that ROS are directly involved in breaking dormancy and germination stimulation [34,35]. ROS generally include compounds such as hydrogen peroxide, superoxide anion, hydroxyl radicals, which are produced during cellular metabolism.…”

Rapid accumulation of NO regulates ABA catabolism and seed dormancy during imbibition in Arabidopsis

“…[23][24][25][26] For example, ABA-induced guard cell closure needs NO participation. 23,[26][27][28] However the mechanism of NO affecting seed dormancy is not clear so far.…”