Protocol for evaluating seedling greening capacity during dark-to-light transition

We present a protocol to evaluate greening capacity in etiolated Arabidopsis seedlings during the critical dark-to-light transition. We describe steps for sample preparation and sowing and then detail procedures for quantifying protochlorophyllide accumulation in darkness, the greening rate upon illumination, and reactive oxygen species levels as an indicator of photo-oxidative stress. This protocol can be used for screening and phenotypic quantification across genetic backgrounds. For complete details of this protocol, please refer to Zhong et al. 1 and Zhong et al. 2 • An integrated framework for assessing greening capacity in Arabidopsis seedlings • Fluorometric quantification of protochlorophyllide in etiolated seedlings • Quantitative scoring of seedling greening rates during dark-to-light transition • Live imaging of reactive oxygen species via H 2 DCFDA staining Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics. We present a protocol to evaluate greening capacity in etiolated Arabidopsis seedlings during the critical dark-to-light transition. We describe steps for sample preparation and sowing and then detail procedures for quantifying protochlorophyllide accumulation in darkness, the greening rate upon illumination, and reactive oxygen species levels as an indicator of photo-oxidative stress. This protocol can be used for screening and phenotypic quantification across genetic backgrounds.