Has a glutathione-disulfide oxidoreductase activity in the presence of NADPH and glutathione reductase. Reduces low molecular weight disulfides and proteins (By similarity). Involved in flower development as a regulator of petal primorida initiation and further petal morphogenesis. May mediate post-translational modifications of target proteins required for normal petal organ initiation and morphogenesis. ROXY1/TGA protein interactions can occur in vivo and support their biological relevance in petal development. May be involved in the regulation of the floral regulator class C gene AG (AGAMOUS). Interacts with TGA2, TGA3, TGA7 and PAN (PubMed:19218396). Interacts with TGA9 and TGA10 in the nucleus (PubMed:20805327). Highly expressed in inflorescences, roots, and siliques. Expressed at lower levels in mature flowers. Expressed first in the inflorescence apex, then in young floral primordia, and in the petal and stamen primordia (PubMed:15728668). Localized to the tapetum and middle layers (PubMed:20805327). Plants show a reduced number of petal primordia and abnormalities during further petal development. Defection in sporogenous cell formation in adaxial anther lobes when associated with the disruption of GRXC8/ROXY2 leading to fertility defects. Belongs to the glutaredoxin family. CC-type subfamily.