Studies on the Involvement of Arabidopsis thaliana Heptahelical Protein 1 in Stoma and Primary Root Responses to Abscisic Acid
Date Issued
2012
Date
2012
Author(s)
Li, Yuan-Fang
Abstract
To understand the involvement of HHP1 in ABA responses in this study, stomatal behavior was examined using hhp1-1 with known stomatal regulator, hydrogen peroxide and nitric oxide. The inhibition of primary root growth by ABA was also examined.
Dark-, ABA-, H2O2-, or NO-induced stomatal closure were observed in both wild-type and hhp1-1. The mutant hhp1-1 was found to have larger stomatal aperture width than wild-type in the absence of regulators, indicating the altered balance of ion strength in guard cells by the loss of HHP1.
The three independent experiments of ABA treatment didn’t show good consistency, so it would not be able to tell whether hhp1-1 stoma has different sensitivity to ABA. The induced stomatal closure by the treatment of H2O2 and NO did not show significant differences between wild-type and hhp1-1 plants. It is suggested that HHP1 acts upstream of H2O2 and NO in the signaling of ABA in guard cells, if hhp1-1 does have less sensitivity in stomatal ABA response.
It was also found that the elongation of primary roots inhibited by ABA is less severe in hhp1-1 mutants than in wild-type plants, indicating that HHP1 promotes the ABA-induced inhibition of primary root elongation.
HHP1 might be involved in ABA-inhibited primary root growth, and HHP1 might act upstream of H2O2 and NO in ABA response in guard cells. Due to the inconsistency in the results of ABA-treated stomatal behavior, the sensitivity of hhp1-1 to ABA in stomatal response was unknown. Improvement is still required to further investigate how HHP1 regulates the ABA responses in plants.
Subjects
abscisic acid
signal transduction
stoma
heptahelical protein 1
nitric oxide
Arabidopsis thaliana
Type
thesis
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