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Dissecting seed dormancy and germination in Aquilegia barbaricina, through thermal kinetics of embryo growth.

Dissecting seed dormancy and germination in Aquilegia barbaricina, through thermal kinetics of embryo growth.

Authors :
Porceddu, M.
Mattana, E.
Pritchard, H. W.
Bacchetta, G.
Kranner, I.
Source :
Plant Biology; Nov2017, Vol. 19 Issue 6, p983-993, 11p
Publication Year :
2017

Abstract

Threshold-based thermal time models provide insight into the physiological switch from the dormant to the non-dormant germinating seed., This approach was used to quantify the different growth responses of the embryo of seeds purported to have morphophysiological dormancy ( MPD) through the complex phases of dormancy release and germination. Aquilegia barbaricina seeds were incubated at constant temperatures (10-25 °C) and 25/10 °C, without pre-treatment, after warm+cold stratification (W+C) and GA<subscript>3</subscript> treatment. Embryo growth was assessed and the time of testa and endosperm rupture scored. Base temperatures ( T<subscript>b</subscript>) and thermal times for 50% (θ<subscript>50</subscript>) of embryo growth and seed germination were calculated., W+C enabled slow embryo growth. W+C and GA<subscript>3</subscript> promoted rapid embryo growth and subsequent radicle emergence. The embryo internal growth base temperature ( T<subscript>be</subscript>) was ca. 5 °C for W+C and GA<subscript>3</subscript>-treated seeds. GA<subscript>3</subscript> treatment also resulted in similar T<subscript>b</subscript> estimates for radicle emergence. The thermal times for embryo growth (θ<subscript>e50</subscript>) and germination (θ<subscript>g50</subscript>) were four- to six-fold longer in the presence of GA<subscript>3</subscript> compared to W+C., A. barbaricina is characterised by a multi-step seed germination. The slow embryo growth during W+C reflects continuation of the maternal programme of development, whilst the thermal kinetics of both embryo and radicle growth after the removal of physiological dormancy are distinctly different. The effects of W+C on the multiphasic germination response in MPD seeds are only partially mimicked by 250 mg·l<superscript>−1</superscript> GA<subscript>3</subscript>. The thermal time approach could be a valid tool to model thermal kinetics of embryo growth and radicle protrusion. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
14358603
Volume :
19
Issue :
6
Database :
Complementary Index
Journal :
Plant Biology
Publication Type :
Academic Journal
Accession number :
125802562
Full Text :
https://doi.org/10.1111/plb.12610