Cytochemical and autoradiographic analyses on the pollen grains of two cultivars of Malus domestica: "Golden Delicious" and "Starkrimson"

• Published in: Rivista di ortoflorofrutticoltura italiana 1980-04, Vol.64 (2), p.111-124
• Main Authors: Avanzi, S., Tagliasacchi, A.M., Forino, L.M.C., Loiero, M., Filiti, N.
• Format: Article
• Language: English
• Subjects: Cell nucleus; Cytoplasm; DNA; Germination; Grains; Metabolism; Pollen; Pollen tubes; Somatic cells; Starches
• ISSN: 0035-5968

Pollen grains of dehiscent anthers of the cultivars of Malus domestica "Golden Delicious" (partially self incompatible) and "Starkrimson" (self incompatible) were studied by Feulgen cytophotometry, autoradiographie Technique, starch staining and germination test. The pollen grain morphology concerning the two cultivars may be assembled into two groups: group a not showing any germinative pores and group b evidenciating well differentiated germinated pores. Both groups are however not homogeneous, as their pollen grain may be characterized by the lack of starch or by the presence of it in variable amount. On the basis of starch grains content, pollen grains of both groups are therefore subdivided into four distinct types. The collected results show that: i) cv. "Starkrimson" is faster in pollen germination as well as in pollen tube elongation than cv. "Golden Delicious"; ii) The percentage of pollen grains of group a and b and of each pollen type within both groups are different in the two cultivars. Particularly large is the difference at the level of starch lacking types within group b, being 10, 8 in cv. "Golden Delicious" and 34,8 in cv. "Starkrimson". iii) In both cultivars generative cells in G₁ (DNA content/nucleus 1C) and in G₂ (DNA content/nucleus 2C) are present. The pollen population of "Golden Delicious" is however characterized by a higher frequently of grains with 2C generative nuclei than pollen population of "Starkrimson" (82% and 55% respectively) while in the cv. "Starkrimson" the pollen grains with 1C generative nuclei are more numerous (79%) in cv. "Starkrimson" and 58% in cv. "Golden Delicious". iv) ³H-Thymidine and ³H-uridine experiments evidence an almost general cytoplasmic labelling. According to the authors this aspect could be the result of a metabolism of plastids and/or mitochondra nucleic acids. Granuli di polline, raccolti da antere deiscenti sono stati studiati in due cultivars di Malus domestica. Le due cultivars sono: "Golden Delicious" parzialmente auto -incompatibile, e "Starkrimson" auto -incompatibile. I metodi usati per la presente indagine sono stati: 1) la citofotometria al Feulgen per la stima del contenuto in DNA del nucleo generativo; 2) la tecnica autoradiografica dopo incorporazione di precursori tritiati del DNA, RNA e proteine; 3) Colorazione dell'amido; 4) test di germinabilità. Per quanto concerne la morfologia i granuli pollinici delle due cultivars possono essere divisi in 2 gruppi: gruppo a i cui granuli