Effect of low water potential on phytochrome-induced germination, endosperm softening and cell-wall mannan degradation in Datura ferox seeds

Phytochrome-induced softening of the micropylar endosperm of Datura ferox seeds is followed by radicle protrusion and preceded by a significant increase in the extractable activity of β-mannanase and β-mannosidase (6 and 3 times over the far-red light controls, respectively) and a decrease in the ma...

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Autores principales: Sánchez, R.A., De Miguel, L., Lima, C., De Lederkremer, R.M.
Formato: JOUR
Materias:
β-mannanase
β-mannosidase
Dormancy
Endosperm softening
Germination
Mannan mobilization
Phytochrome
Water potential
Datura
Datura ferox
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_09602585_v12_n3_p155_Sanchez
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_09602585_v12_n3_p155_Sanchez2023-10-03T15:53:42Z Effect of low water potential on phytochrome-induced germination, endosperm softening and cell-wall mannan degradation in Datura ferox seeds Sánchez, R.A. De Miguel, L. Lima, C. De Lederkremer, R.M. β-mannanase β-mannosidase Dormancy Endosperm softening Germination Mannan mobilization Phytochrome Water potential Datura Datura ferox Phytochrome-induced softening of the micropylar endosperm of Datura ferox seeds is followed by radicle protrusion and preceded by a significant increase in the extractable activity of β-mannanase and β-mannosidase (6 and 3 times over the far-red light controls, respectively) and a decrease in the mannan content of the micropylar endosperm cell walls. This relationship between phytochrome-induced germination, endosperm softening and mannan degradation was studied in Datura ferox seeds subjected to a range of water potentials during the presence of Pfr. Low water potential inhibited the decrease in mannose-rich cell-wall insoluble polysaccharides, the increase in activity of β-mannosidase and endosperm softening. A good correlation was found between activity of β-mannosidase measured at 45 h after exposure to a red light pulse and germination counted 24 h later when, with different external water potentials, germination varied between 0 and 90%. In contrast, no inhibitory effect of low water potential on in vitro β-mannanase activity was detected. We suggest that the in vivo action of β-mannanase might be limited by accumulation of manno-oligosaccharides caused by inhibition of β-mannosidase. These data are consistent with the concept of a link between mannan mobilization and endosperm softening. Part of the effect of low water potential on Pfr-induced germination may be mediated by inhibition of β-mannosidase activity, with consequences for mannan hydrolysis and endosperm softening. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_09602585_v12_n3_p155_Sanchez
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic β-mannanase
β-mannosidase
Dormancy
Endosperm softening
Germination
Mannan mobilization
Phytochrome
Water potential
Datura
Datura ferox
spellingShingle β-mannanase
β-mannosidase
Dormancy
Endosperm softening
Germination
Mannan mobilization
Phytochrome
Water potential
Datura
Datura ferox
Sánchez, R.A.
De Miguel, L.
Lima, C.
De Lederkremer, R.M.
Effect of low water potential on phytochrome-induced germination, endosperm softening and cell-wall mannan degradation in Datura ferox seeds
topic_facet β-mannanase
β-mannosidase
Dormancy
Endosperm softening
Germination
Mannan mobilization
Phytochrome
Water potential
Datura
Datura ferox
description Phytochrome-induced softening of the micropylar endosperm of Datura ferox seeds is followed by radicle protrusion and preceded by a significant increase in the extractable activity of β-mannanase and β-mannosidase (6 and 3 times over the far-red light controls, respectively) and a decrease in the mannan content of the micropylar endosperm cell walls. This relationship between phytochrome-induced germination, endosperm softening and mannan degradation was studied in Datura ferox seeds subjected to a range of water potentials during the presence of Pfr. Low water potential inhibited the decrease in mannose-rich cell-wall insoluble polysaccharides, the increase in activity of β-mannosidase and endosperm softening. A good correlation was found between activity of β-mannosidase measured at 45 h after exposure to a red light pulse and germination counted 24 h later when, with different external water potentials, germination varied between 0 and 90%. In contrast, no inhibitory effect of low water potential on in vitro β-mannanase activity was detected. We suggest that the in vivo action of β-mannanase might be limited by accumulation of manno-oligosaccharides caused by inhibition of β-mannosidase. These data are consistent with the concept of a link between mannan mobilization and endosperm softening. Part of the effect of low water potential on Pfr-induced germination may be mediated by inhibition of β-mannosidase activity, with consequences for mannan hydrolysis and endosperm softening.
format JOUR
author Sánchez, R.A.
De Miguel, L.
Lima, C.
De Lederkremer, R.M.
author_facet Sánchez, R.A.
De Miguel, L.
Lima, C.
De Lederkremer, R.M.
author_sort Sánchez, R.A.
title Effect of low water potential on phytochrome-induced germination, endosperm softening and cell-wall mannan degradation in Datura ferox seeds
title_short Effect of low water potential on phytochrome-induced germination, endosperm softening and cell-wall mannan degradation in Datura ferox seeds
title_full Effect of low water potential on phytochrome-induced germination, endosperm softening and cell-wall mannan degradation in Datura ferox seeds
title_fullStr Effect of low water potential on phytochrome-induced germination, endosperm softening and cell-wall mannan degradation in Datura ferox seeds
title_full_unstemmed Effect of low water potential on phytochrome-induced germination, endosperm softening and cell-wall mannan degradation in Datura ferox seeds
title_sort effect of low water potential on phytochrome-induced germination, endosperm softening and cell-wall mannan degradation in datura ferox seeds
url http://hdl.handle.net/20.500.12110/paper_09602585_v12_n3_p155_Sanchez
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