Microporous membrane and culture medium affect in vitro seedling development of Dalbergia nigra (Vell.) Ex Benth. (Fabaceae) by modulation of the protein profile and accumulation of ethylene and CO 2

The use of sealing lids with microporous membranes (MM) is relevant to understanding the role of gas exchange on changes in ethylene and polyamine (PA) contents and proteome profiles during seedling growth. This study aimed to evaluate the influence of sealing lids and culture media, Murashige and Skoog (MS) and woody plant medium (WPM), on the in vitro seed germination and seedling development of Dalbergia nigra and on the content of ethylene, CO 2 , PAs, photosynthetic index, and protein profile. Sealing lids with MM allowed higher germination of seeds. Higher CO 2 and leaf abscission were observed in seedlings grown in all culture media without an MM. The contents of total free PAs and free putrescine were significantly affected by the different culture media but not by the MM. A total of 545 proteins were identified, of which 101 were differentially accumulated (DAP) in seedlings grown in MS culture medium with MM compared to those grown without MM. Among DAPs, the presence of aspartate aminotransferase protein, related to ethylene biosynthesis, in seedlings grown in culture tubes containing MS culture medium without an MM was associated with greater ethylene accumulation and, consequently, greater leaf abscission. Photosynthesis- and carbon metabolism-related proteins accumulated in seedlings grown in MS culture medium sealed with MM were affected by gas exchange and associated with a higher photosynthetic index. This is the first study showing the effects of gas exchange promotion on in vitro seed germination and seedling development in D. nigra and its interaction with ethylene and protein accumulation and is relevant for optimizing in vitro micropropagation studies in this endangered woody species from the Brazilian rainforest.