Cold‐induced Chromosome Regions and Karyosystematics in Sambucus and Viburnum

Abstract

The genera Viburnum, Sambucus and Lonicera have been investigated for chromosome number and karyomorphology including Giemsa‐C‐banding, fluorochrome (DAPI/CMA) banding and cold treatment. Cold‐induced undercontracted chromosome regions (CIRs) are found in Viburnum and Sambucus for the first time and are apparently identical with larger hc regions, shown by Giemsa C‐banding. Certain narrow C‐bands are not cold‐sensitive. CIRs frequently react brightly CMA‐positive in Viburnum and Sambucus, while DAPI fluorescence is virtually ineffective. The occurrence of CIRs within plants is possibly linked to certain nuclear characters such as large chromosomes and continuous condensation behaviour. Cold‐induction has possibly also some influence on euchromatin condensation characteristics in prophasic chromosomes. Several karyological characters point to a closer relationship between Viburnum, Sambucus and Adoxa: Relatively large chromosomes, continuous condensation behaviour, reticulate to semireticulate interphase nuclei and presence of CIRs. These genera appear isolated from Lonicera and the Caprifoliaceae s.str., which differ remarkably in karyomorphology.

Sambucus nigraL.

“…The difference may have been due to a higher degree of chromatin condensation. Cold‐induced regions in the chromosomes of S. nigra were reported by Benko‐Iseppon & Morawetz (1993). The 2C nuclear DNA amount was recorded as 3.1 pg by Grime et al .…”

Patterns of heterochromatin distribution in plant chromosomes

“…HC may be revealed by different cytological techniques, with identical or very similar results (Vosa, 1976b;Lozano et al, 1990;Berg and Greilhuber, 1993). Conventional staining techniques may sometimes show heteropycnotic regions that form the so-called prophase condensation patterns (Fukui and Mukai, 1988;Ikeda, 1988;Benko-Iseppon and Morawetz, 1993). Such regions have often been confused with HC patterns which may be very different from each other (see Morawetz, 1981a;Guerra, 1988a).…”

Phylogenetic Relationships of Sambucus and Adoxa (Adoxoideae, Adoxaceae) Based on Nuclear Ribosomal ITS Sequences and Preliminary Morphological Data

“…The name Adoxoideae has been applied by Thorne (1992) to this clade, which is characterized by such morphological features as compound leaves, extrorse anthers (at least at maturity), and the Adoxa-type embyo sac. The Sambucus-Adoxa clade appears to be related to Viburnum (references above, also see Benko-Iseppon 1993: Erbar 1994Backlund and Donoghue 1996) and the clade stemming from the common ancestor of these three groups has been called Adoxaceae by several authors (Donoghue 1983b;Thorne 1992;Judd et al 1994;. Phylogenetic relationships within Viburnum have received some attention (Donoghue 1983b(Donoghue , 1985Donoghue and Baldwin 1993;Donoghue and Sytsma 1993), but little work has been done on the phylogeny of Adoxoideae.…”