caa a22 4500 397522010 CHVBK 20180308164635.0 cr unu---uuuuu 161202e199505 xx s 000 0 eng 10.1093/jxb/46.5.577 doi (NATIONALLICENCE)oxford-10.1093/jxb/46.5.577 Production and secretion of α-galactosidase and endo-β-mannanase by carob (Ceratonia siliqua L.) endosperm protoplasts [Elektronische Daten] [Fanouris Kontos, Caroline G. Spyropoulos] Viable protoplasts were isolated for the first time from mature carob (Ceratonia siliqua L.) endosperm tissue. After 5 d of incubation 75% of the protoplasts were viable. During incubation they underwent vacuolation and produced the carob endosperm hydrolases, agalactosidase and endo-β-mannanase, which were secreted in the incubation medium. The secretion of both enzymes were under Ca2+ control. Many characteristics of α-galactosidase and endo-β-mannanase production by protoplasts were the same as those of whole endosperms: their production did not require any hormonal signal and was inhibited in the presence of ABA or the leachate from the carob endosperm/seed coat. Moderate water stress (—2.0 MPa) neither affected the activity of these hydrolases nor their secretion by endosperm protoplast. However, when the osmoticum of protoplast incubation medium was higher, the production and secretion of both hydrolases were reduced. Comparison of the hydrolases activities in the incubation media of leached carob endosperms, which were incubated under normal and water stress (—1.5 MPa) conditions, with the activities of the protoplast-secreted hydrolases indicated that (i) carob endosperm cell wall acts as a barrier for the secreted enzymes and (ii) that water stress reduces the cell wall porosity of the carob endosperm cells, and thus the release of the secreted α-galactosidase and endo-β-mannanase is inhibited. The isolation of carob endosperm protoplasts offers a potent experimental system for the study of aspects of endosperm cell physiology, such as enzyme secretion © Oxford University Press Research Papers nationallicence Abscisic acid nationallicence carob endosperm nationallicence Ceratonia siliqua L nationallicence endo-β-mannanase nationallicence α-galactosidase nationallicence leachate nationallicence protoplasts nationallicence water stress nationallicence Kontos Fanouris Institute of General Botany, Department of Biology, University of Athens, 15784 Athens, Greece aut Spyropoulos Caroline G. Institute of General Botany, Department of Biology, University of Athens, 15784 Athens, Greece aut Journal of Experimental Botany Oxford University Press 46/5(1995-05), 577-583 0022-0957 46:5<577 1995 46 exbotj https://doi.org/10.1093/jxb/46.5.577 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/jxb/46.5.577 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kontos Fanouris Institute of General Botany, Department of Biology, University of Athens, 15784 Athens, Greece aut NATIONALLICENCE 700 1- Spyropoulos Caroline G. Institute of General Botany, Department of Biology, University of Athens, 15784 Athens, Greece aut NATIONALLICENCE 773 0- Journal of Experimental Botany Oxford University Press 46/5(1995-05), 577-583 0022-0957 46:5<577 1995 46 exbotj Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford