Cold stratification, temperature, light, GA3, and KNO3 effects on seed germination of Primula beesiana from Yunnan, China

Abstract

Primula beesiana Forr. is an attractive wildflower endemically distributed in the wet habitats of subalpine/alpine regions of southwestern China. This study is an attempt to understand how this plant adapts to wet habitats and high altitudes. Specifically, we examined the effects of cold stratification, light, GA 3 , KNO 3 , and temperature on P. beesiana seed germination. KNO 3 and GA 3 increased germination percentage and germination rate compared to control treatments at 15/5 and 25/15 °C. Untreated seeds germinated well (> 80%) at higher temperatures (20, 25 and 28 °C), whereas at lower (5, 10 and 15 °C) and extremely high temperatures (30 and 32 °C) germination decreased significantly. However, after cold stratification (4–16 weeks), the germination percentage of P. beesiana seeds at low temperatures (5–15 °C) and the germination rate at high temperatures (30 °C) increased significantly, suggesting that P. beesiana has type 3 non-deep physiological dormancy. The base temperature and thermal time for germination decreased in seeds that were cold stratified for 16 weeks. Cold-stratified seeds incubated at fluctuating temperatures (especially at 15/5 °C) had significantly high germination percentages and germination rates in light, but not in dark, compared to the corresponding constant temperature (10 °C). Seeds had a strict light requirement at all temperatures, even after experiencing cold stratification; however, the combinations of cold stratification and fluctuating temperature increased germination when seeds were transferred from dark to light. Such dormancy/germination responses to light and temperature are likely mechanisms that ensure germination occurs only in spring and at/near the soil surface, thus avoiding seedling death by freezing, inundation and/or germination deep in the soil.

Practical Methods for Breaking Seed Dormancy in a Wild Ornamental Tulip Species Tulipa thianschanica Regel

“…Nitrogenous compounds, such as nitrate, NO and cyanide, have a positive effect on the release of dormancy [39][40][41]. Wang reported that the application of nitrate in potato promoted the expression of a gene involved in ABA catabolism (StCYP707A1) [42].…”

Exogenous 5-azaCitidine accelerates flowering and external GA3 increases ornamental value in Iranian Anemone accessions

“…External GA 3 can act as a stimulator for internal GA 3 synthesis 17 . Gibberellins play a role in breaking the dormancy, accelerating the germination and flowering time 49 and increasing the vegetative growth by affecting the synthesis and activity of hydrolyzing enzymes in storage resources 50 . In addition, gibberellins improve the photosynthetic efficiency by enhancing photosynthetic enzymes and leaf area index and increasing the nutrient uptake 51 .…”

Exogenous Gibberellin Promotes the Germination of Phellodendron Chinense Schneid Seeds by Regulating the Expression of Phytohormone Related Genes and Anabolic Proteins

“…The plant growth regulators are divided into ve classes, one of them being Gibberellin (GA), which is a diterpenoid compound, and the most active arti cially synthesized hormone [28,29]. A previous studies showed that the germination rate of Primula beesiana seeds under 15/5℃ treatment was less than 10%, but exogenous GA 3 signi cantly increased seed germination [30]. In this study, exogenous GA 3 signi cantly promoted seed germination, enhanced germination rate, promoted the growth and elongation of the hypocotyl in Phellodendron chinense Schneid ( Fig.…”