A morphological and biochemical analysis of embryo maturation during yellow cypress seed development

Abstract

Embryo maturation in yellow cypress (Chamaecyparisnootkatensis (D. Don) Spach) seeds was studied at the morphological, anatomical, and biochemical level over the second and third seasons of seed development. Monthly cone collections were made from six open-pollinated families from two seed orchards. The average number of seeds and embryos per cone for each family was 8.8 and 4.6, respectively. Sixty to 70% of those embryos harvested from early collection dates (December 1988–March 1989) were precotyledonary (stages 1 and 2), with an average length of 0.5 mm. By April 1989 a distinct shift in the proportion of precotyledonary (stages 1 and 2) to late cotyledonary (stages 5 and 6) embryos was observed. The frequency of late cotyledonary (stages 5 and 6) embryos was 100% by August 1989 of the third growing season and averaged 2.5 mm in overall size. Moisture loss and dry weight accumulation were still progressing at the time of seed dispersal and may suggest embryo immaturity. Anatomical studies revealed protein and lipid bodies were present as early as the stage 1 embryo and became increasingly abundant during maturation. The major storage proteins isolated from protein bodies of embryo tissues had apparent molecular masses of 37, 36, 35, 34, 28, 26, and 24 kDa. Based on their solubility characteristics, the proteins were identified as buffer-soluble albumins that contained intermolecular disulfide linkages. Storage proteins were detected in early stage embryos and increased in abundance throughout maturation. Upon germination, storage proteins slowly declined to low levels by 16 and 20 days postgermination. The evidence suggests that yellow cypress embryos may be immature at the time of seed dispersal and this immaturity may contribute to the poor germination exhibited by this species.

Critical phases in the seed development of common juniper (Juniperus communis)

“…2008); a process that already started prior to fertilisation (Bonner 2008). Further maturation of the seed is accomplished with a certain amount of seed drying (Kurz et al. 1994).…”

Genetic diversity of Spanish fir (Abies pinsapo Boiss.) populations by means of megagametophyte storage proteins

“…Only few studies have been carried out on Gymnosperms megagametophyte storage proteins and in conifers they have mainly been based on biochemical characteristics of these proteins (Allona et al, 1994;Kurz et al, 1994;Piovesan et al, 1993). Likewise, our team used these proteins as markers to evaluate the genetic diversity of the stone pine (P. pinea L.), revealing a high level of variation in the studied populations which suggested that this technique could be useful to assess the genetic diversity in conifers (Alvarez et al, 2004).…”