virescence

Virescence is a botanical term that describes the appearance of green coloration in plant tissues that are normally non-green, such as petals, flowers, fruits, or young shoots. This green hue results from the de novo development or persistence of chlorophyll-containing plastids in these tissues, giving them chlorophyll-based pigmentation when they would typically display other colors. Virescence is distinct from ordinary leaf green color and from chlorosis or variegation, as it reflects chloroplast development in tissues where chloroplasts are usually absent or reduced.

Causes of virescence include genetic mutations that affect pigment biosynthesis or plastid differentiation, leading to greenish tissues in parts of the plant that are normally colored differently. It can also occur as a response to certain plant viruses or to environmental conditions that alter development and pigment synthesis. In some cases, virescence may be temporary or stage-specific, appearing during a particular part of development or under specific cultural conditions. In horticulture and plant breeding, virescence can be examined as a trait of interest for its impact on flower or fruit coloration, while in botany it serves as a case study in plastid biology and chlorophyll biosynthesis.