The former plant population survey has shown that three genetically-related species, Caraganamicrophylla Lam., C. davazamcii Sancz. and C. korshinskii Kom., form a geographical replacement series inNei Mongol Plateau....The former plant population survey has shown that three genetically-related species, Caraganamicrophylla Lam., C. davazamcii Sancz. and C. korshinskii Kom., form a geographical replacement series inNei Mongol Plateau. The present study on population distribution, taxonomy, morphology, development andgenetic structure demonstrated that the geographical distribution of these three species was successiveand in gradual change, thus forming a geographical cline which extended from the east to the west of NeiMongol Plateau. With an analysis of climate change over time, it was considered that the formation of thisgeographical cline was a result of plant adaptation to its natural environment.展开更多
The characteristics of photosynthesis and water metabolism of Caragana microphylla Lam.,C. davazamcii Sancz. and C. korshinskii Kom. populations in different sites (117.6o-105.7o E, 44.6o-38.8o N)were studied. (1) Fro...The characteristics of photosynthesis and water metabolism of Caragana microphylla Lam.,C. davazamcii Sancz. and C. korshinskii Kom. populations in different sites (117.6o-105.7o E, 44.6o-38.8o N)were studied. (1) From the east to the west, the responses of the three species to photosyntheticallyavailable radiation (PAR) in net photosynthesis rate increased, the relative humidity of the air whichcorresponded to the occurrence of maximum photosynthesis rate decreased, and the corresponding airtemperature increased. Along the same gradient, the before-noon superiority of the photosynthesis be-came evident, and the photosynthesis rate and the light use efficiency (LUE ) increased, while the transp-iration rate decreased, thus the water use efficiency (WUE ) increased notably, and the leaf water contentdecreased gradually. From the east to the west, the plants took a water-saving strategy step by step withhigher photosynthesis rate and lower transpiration rate. These physiological changes in the plants wereadaptable to the conditions of light, temperature and humidity in the habitat of the plants, and might be thebiological foundation for the geographical transition among C. microphylla , C. davazamcii and C. korshinskii.(2) The adaptation of photosynthetic system of C. microphylla , C. davazamcii and C. korshinskii to PAR, airhumidity and temperature exhibited the interspecific continuity, which was consistent with theenvironmental gradient. In different species and different sites, the diurnal changes of net photosynthesisrate, the daily cumulative value of net photosynthesis, the diurnal changes of transpiration rate, the dailycumulative value of transpiration, the water use efficiency and the diurnal changes of leaf water contentvaried with longitudinal descent (from the east to the west). The characteristics of photosynthesis andwater metabolism indicated that the geographical transition among C. microphylla , C. davazamcii and C.korshinskii was in gradual change, and these three species formed a geographical cline.展开更多
Aims In forest ecosystems,different types of regression models have been frequently used for the estimation of aboveground biomass,where Ordinary Least Squares(OLS)regression models are the most common prediction mode...Aims In forest ecosystems,different types of regression models have been frequently used for the estimation of aboveground biomass,where Ordinary Least Squares(OLS)regression models are the most common prediction models.Yet,the relative performance of Bayesian and OLS models in predicting aboveground biomass of shrubs,especially multi-stem shrubs,has relatively been less studied in forests.Methods In this study,we developed the biomass prediction models for Caragana microphylla Lam.which is a widely distributed multi-stems shrub,and contributes to the decrease of wind erosion and the fixation of sand dunes in the Horqin Sand Land,one of the largest sand lands in China.We developed six types of formulations under the framework of the regression models,and then,selected the best model based on specific criteria.Consequently,we estimated the parameters of the best model with OLS and Bayesian methods with training and test data under different sample sizes with the bootstrap method.Lastly,we compared the performance of the OLS and Bayesian models in predicting the aboveground biomass of C.microphylla.Important Findings The performance of the allometric equation(power=1)was best among six types of equations,even though all of those models were significant.The results showed that mean squared error of test data with non-informative prior Bayesian method and the informative prior Bayesian method was lower than with the OLS method.Among the tested predictors(i.e.plant height and basal diameter),we found that basal diameter was not a significant predictor either in OLS or Bayesian methods,indicating that suitable predictors and well-fitted models should be seriously considered.This study highlights that Bayesian methods,the bootstrap method and the type of allometric equation could help to improve the model accuracy in predicting shrub biomass in sandy lands.展开更多
文摘The former plant population survey has shown that three genetically-related species, Caraganamicrophylla Lam., C. davazamcii Sancz. and C. korshinskii Kom., form a geographical replacement series inNei Mongol Plateau. The present study on population distribution, taxonomy, morphology, development andgenetic structure demonstrated that the geographical distribution of these three species was successiveand in gradual change, thus forming a geographical cline which extended from the east to the west of NeiMongol Plateau. With an analysis of climate change over time, it was considered that the formation of thisgeographical cline was a result of plant adaptation to its natural environment.
文摘The characteristics of photosynthesis and water metabolism of Caragana microphylla Lam.,C. davazamcii Sancz. and C. korshinskii Kom. populations in different sites (117.6o-105.7o E, 44.6o-38.8o N)were studied. (1) From the east to the west, the responses of the three species to photosyntheticallyavailable radiation (PAR) in net photosynthesis rate increased, the relative humidity of the air whichcorresponded to the occurrence of maximum photosynthesis rate decreased, and the corresponding airtemperature increased. Along the same gradient, the before-noon superiority of the photosynthesis be-came evident, and the photosynthesis rate and the light use efficiency (LUE ) increased, while the transp-iration rate decreased, thus the water use efficiency (WUE ) increased notably, and the leaf water contentdecreased gradually. From the east to the west, the plants took a water-saving strategy step by step withhigher photosynthesis rate and lower transpiration rate. These physiological changes in the plants wereadaptable to the conditions of light, temperature and humidity in the habitat of the plants, and might be thebiological foundation for the geographical transition among C. microphylla , C. davazamcii and C. korshinskii.(2) The adaptation of photosynthetic system of C. microphylla , C. davazamcii and C. korshinskii to PAR, airhumidity and temperature exhibited the interspecific continuity, which was consistent with theenvironmental gradient. In different species and different sites, the diurnal changes of net photosynthesisrate, the daily cumulative value of net photosynthesis, the diurnal changes of transpiration rate, the dailycumulative value of transpiration, the water use efficiency and the diurnal changes of leaf water contentvaried with longitudinal descent (from the east to the west). The characteristics of photosynthesis andwater metabolism indicated that the geographical transition among C. microphylla , C. davazamcii and C.korshinskii was in gradual change, and these three species formed a geographical cline.
基金supported by the National Natural Science Foundation of China(31870709)Economic and Social Development Project of Liaoning Province(2020lslktqn037)+1 种基金A.Ali was supported by the Special Project for Introducing Foreign Talents-Jiangsu‘Foreign Expert Hundred People Program’(BX2019084)Metasequoia Faculty Research Startup Funding at Nanjing Forestry University(163010230).
文摘Aims In forest ecosystems,different types of regression models have been frequently used for the estimation of aboveground biomass,where Ordinary Least Squares(OLS)regression models are the most common prediction models.Yet,the relative performance of Bayesian and OLS models in predicting aboveground biomass of shrubs,especially multi-stem shrubs,has relatively been less studied in forests.Methods In this study,we developed the biomass prediction models for Caragana microphylla Lam.which is a widely distributed multi-stems shrub,and contributes to the decrease of wind erosion and the fixation of sand dunes in the Horqin Sand Land,one of the largest sand lands in China.We developed six types of formulations under the framework of the regression models,and then,selected the best model based on specific criteria.Consequently,we estimated the parameters of the best model with OLS and Bayesian methods with training and test data under different sample sizes with the bootstrap method.Lastly,we compared the performance of the OLS and Bayesian models in predicting the aboveground biomass of C.microphylla.Important Findings The performance of the allometric equation(power=1)was best among six types of equations,even though all of those models were significant.The results showed that mean squared error of test data with non-informative prior Bayesian method and the informative prior Bayesian method was lower than with the OLS method.Among the tested predictors(i.e.plant height and basal diameter),we found that basal diameter was not a significant predictor either in OLS or Bayesian methods,indicating that suitable predictors and well-fitted models should be seriously considered.This study highlights that Bayesian methods,the bootstrap method and the type of allometric equation could help to improve the model accuracy in predicting shrub biomass in sandy lands.
