biologia plantarum

Biologia plantarum 45:539-544, 2002 | DOI: 10.1023/A:1022321008309

Some Properties of Proteolytic Enzymes and Storage Proteins in Recalcitrant and Orthodox Seeds of Araucaria

L. Galleschi¹, A. Capocchi¹, S. Ghiringhelli¹, F. Saviozzi¹

¹ Department of Botanical Sciences, University of Pisa, Pisa, Italy

Araucaria bidwillii Hook. and Araucaria cunninghamii Don D. are two species of conifers whose seeds belong to different physiological categories: A. bidwillii seeds are recalcitrant, while A. cunninghamii seeds are orthodox. The extraction of enzymes and storage proteins was carried out from A. bidwillii and A. cunninghamii megagametophytes. The endopeptidase activities of both species were assayed with azocasein and with haemoglobin; the exopeptidase activities were detected by various N-carbobenzyloxy-dipeptides and L-leucine p-nitroanilide. The use of appropriate proteinase inhibitors, i.e. pepstatin A, ethylenediaminetetraacetic acid and trans-epoxysuccinyl-L-leucylamido-(4-guanidino)butane, showed the presence of aspartic and metallo proteinases and the absence of the cysteine ones both in A. bidwillii and in A. cunninghamii ungerminated seeds. Since the results do not show differences between the types of enzymes in the ungerminated araucarian seeds and those present in some ungerminated angiosperm seeds (barley, wheat, maize, rice, buckwheat), we conclude that their physiological role is similar. The electrophoretical analyses of soluble and insoluble storage proteins of A. cunninghamii showed patterns similar to those found in other gymnosperms, while the storage protein patterns of A. bidwillii seeds were rather atypical.

Keywords: Araucaria bidwillii Hook.; Araucaria cunninghamii Don D.; globulins; megagametophyte; protease inhibitors; sodium dodecyl sulfate polyacrylamide gel electrophoresis

Subjects: aminopeptidase; Araucaria bidwillii; Araucaria cunninghamii; azocaseinase; carboxypeptidase; globulins; haemoglobinase; megagametophyte, enzymes; peptidases; protease inhibitors; proteolytic enzymes; recalcitrant and orthodox seeds; seed enzymes; seed, recalcitrant and orthodox; seed-storage proteins

Published: December 1, 2002Show citation