Fig. 2.—

DNA histograms of Vanilla tissues. (A) Vanilla planifolia. In vanilla plants: population of 2C nuclei was expected when using the emerging apex or a very young leaf (enclosing the apex, arrow 1), the heart of a lateral bud (arrow 2), or notably the node (arrow 3); very young aerial root (arrow 4). (B) DNA histograms from Vanilla pompona somatic tissues (tomato as internal standard). A solid horizontal bar () represents the increment equivalent to a doubling, for example, 2C–4C for tomato. Note that euploid nuclei are sometimes difficult to assess in young apical tissue and young leaf, complicating the estimations of genome-size and of the endoreplication process itself. Contrastingly, in nodal tissue, the 2C nuclei, essential for assessing genome-size, constituted exceptionally a fifth of this sample of orchid nuclei. Populations of larger nuclei were also evident: 4E, 8E, 16E, 32E, and a trace of 64E.