Effect of seed size and sub-zero imbibition-temperature on the thermal time model of winterfat (Eurotia lanata (Pursh) Moq.)

摘要: Thermal time has been widely used to quantify and model seed germination. However, several assumptions in the thermal remain untested. The purpose of this study was test variations parameters among size classes sub-zero imbibition-temperature treatments using two non-dormant collections winterfat ( Eurotia lanata). Seeds originating from Utah, USA, were imbibed at temperature for 0, 1, 3 5 days then germinated 2, 5, 10, 15, 20, 25 ◦ C. Estimated base (Tb) lower large class (−4.48 C) than small (−3.53 C). 50% germination (θT(50)) standard deviation times (σθT ) not significantly different between classes. faster after imbibition temperature, but enhanced rate mainly attributed accumulation during rather often speculated physiological changes. A index (TGRI) proposed, which successfully accounted imbibition. Sub-zero did, however, alter Tb, θT(50) σθT both as evidenced by higher fit modified original model. Base larger seeds, enables seeds accumulate more a given temperature. This is particularly important species such because germinate early season. © 2003 Elsevier B.V. All rights reserved.