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 habit...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,GA3,KNO3,and temperature on P.beesiana seed germination.KNO3 and GA3 increased germination percentage and germination rate compared to control treatments at 15/5 and 25/15℃.Untreated seeds germinated well(>80%)at higher temperatures(20,25 and 28℃),whereas at lower(5,10 and15℃)and extremely high temperatures(30 and 32℃)germination decreased significantly.However,after cold stratification(4-16 weeks),the germination percentage of P.beesiana seeds at low temperatures(5-15℃)and the germination rate at high temperatures(30℃)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℃)had significantly high germination percentages and germination rates in light,but not in dark,compared to the corresponding constant temperature(10℃).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.展开更多
The germination experiment was started on March 3,2004,and seeds were collected from July to October in 2003.We analyzed the percentage of germination,days to first germination,germination period and days to 50%germin...The germination experiment was started on March 3,2004,and seeds were collected from July to October in 2003.We analyzed the percentage of germination,days to first germination,germination period and days to 50%germination.Among the 54 examined species,26 species exceeded 80%germination,11 species exceeded 60%–80%germination,8 exceeded 40%–0%,5 exceeded 20%–40%,and 4 showed less than 20%.A principalcomponent analysis revealed that the species were distributed along two statistically independent axes,the first primarily represented the germination rate and the second represented the time of germination process.Based on scores of germination characteristics,cluster analysis of the 54 gramineous species could be divided into 4 distinct groups:rapid,slow,intermediate germinating(germination percentage>50%),and low germinating(germination percentage<50%).The meaning of different groups to the vegetation regeneration was discussed.展开更多
基金the National Key R&D Program of China(2017YF0505200 to H.Sun)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA 20050203 to H.Sun)+1 种基金the Key Program of the National Natural Science Foundation of China(U1802232 to H.Sun)National Natural Science Foundation of China(grant 31700284 to D.L.Peng,31670206 to Z.M.Li and 31900185 to L.E.Yang)。
文摘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,GA3,KNO3,and temperature on P.beesiana seed germination.KNO3 and GA3 increased germination percentage and germination rate compared to control treatments at 15/5 and 25/15℃.Untreated seeds germinated well(>80%)at higher temperatures(20,25 and 28℃),whereas at lower(5,10 and15℃)and extremely high temperatures(30 and 32℃)germination decreased significantly.However,after cold stratification(4-16 weeks),the germination percentage of P.beesiana seeds at low temperatures(5-15℃)and the germination rate at high temperatures(30℃)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℃)had significantly high germination percentages and germination rates in light,but not in dark,compared to the corresponding constant temperature(10℃).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.
基金supported by the Chinese Key Project for Nature Science (No.90202009).
文摘The germination experiment was started on March 3,2004,and seeds were collected from July to October in 2003.We analyzed the percentage of germination,days to first germination,germination period and days to 50%germination.Among the 54 examined species,26 species exceeded 80%germination,11 species exceeded 60%–80%germination,8 exceeded 40%–0%,5 exceeded 20%–40%,and 4 showed less than 20%.A principalcomponent analysis revealed that the species were distributed along two statistically independent axes,the first primarily represented the germination rate and the second represented the time of germination process.Based on scores of germination characteristics,cluster analysis of the 54 gramineous species could be divided into 4 distinct groups:rapid,slow,intermediate germinating(germination percentage>50%),and low germinating(germination percentage<50%).The meaning of different groups to the vegetation regeneration was discussed.
