Relict subtropical coniferous forests in China face severe fragmentation,resulting in declining populations,and some are under significant threat from invasive alien species.Despite the crucial importance of understan...Relict subtropical coniferous forests in China face severe fragmentation,resulting in declining populations,and some are under significant threat from invasive alien species.Despite the crucial importance of understanding forest dynamics,knowledge gaps persist,particularly regarding the impact of invasive plants on vulnerable natives like Keteleeria evelyniana.In this study,we investigated the impact of invasive plants on the regeneration of forests dominated by K.evelyniana,a subtropical relict species in southwestern China.For this purpose,we characterized forest dynamics of 160 forest plots featuring K.evelyniana as the primary dominant species and determined whether the presence of invasive plants was correlated with regeneration of K.evelyniana.We identified four distinct forest types in which K.evelyniana was dominant.We found that radial growth of K.evelyniana trees is faster in younger ageclasses today than it was for older trees at the same age.The population structure of K.evelyniana in each forest type exhibited a multimodal age-class distribution.However,three forest types lacked established saplings younger than 10 years old,a situation attributed to the dense coverage of the invasive alien Ageratina adenophora.This invasive species resulted in a reduction of understory species diversity.Additionally,our analysis uncovered a significant negative correlation in phylogenetic relatedness(net relatedness index)between native and invasive alien plant species in eastern Yunnan.This suggests closely related invasive species face heightened competition,hindering successful invasion.Taken together,our findings indicate that successful establishment and habitat restoration of K.evelyniana seedling/saplings require effective measures to control invasive plants.展开更多
本文报道了新发现的一种病害——油杉枝瘤病,它是云南省中部云南油杉林内常见的一种重要病害,由王氏油杉盘针孢(Libertella wangii Ren et Zhou)所引起。受害林木在枝条上形成肿瘤,幼树主干上也有发生。肿瘤略呈球形,常包围枝条,大的肿...本文报道了新发现的一种病害——油杉枝瘤病,它是云南省中部云南油杉林内常见的一种重要病害,由王氏油杉盘针孢(Libertella wangii Ren et Zhou)所引起。受害林木在枝条上形成肿瘤,幼树主干上也有发生。肿瘤略呈球形,常包围枝条,大的肿瘤直径可达20cm。病原菌菌丝体在肿瘤表皮下形成分生孢子盘,成熟时表皮开裂,遇潮湿天气,从表皮裂隙中逸出橙色卷须状分生孢子角,分生孢子籍雨滴飞溅和气流传播。从嫩枝顶芽侵入。受害幼树应加以清除,必要时可在春末夏初喷撒杀菌剂以保护幼树。展开更多
【目的】为了解云南油杉叶绿体基因密码子的偏好性使用模式。以云南油杉叶绿体基因组密码子为研究对象,筛选出41条蛋白编码序列,进行密码子偏好性分析,进一步揭示密码子组成特点及影响密码子偏好的因素,确定其最优密码子,为云南油杉开...【目的】为了解云南油杉叶绿体基因密码子的偏好性使用模式。以云南油杉叶绿体基因组密码子为研究对象,筛选出41条蛋白编码序列,进行密码子偏好性分析,进一步揭示密码子组成特点及影响密码子偏好的因素,确定其最优密码子,为云南油杉开展叶绿体基因工程提供理论依据。【方法】利用Codon W 1.4.2和CUSP在线软件对云南油杉叶绿体基因密码子进行了中性绘图分析、ENC-plot、PR2-plot分析和对应性分析,分析密码子偏好性的影响因素,并从中得到最优密码子。【结果】云南油杉叶绿体基因组密码子不同位置上的GC含量依次是GC_(1)(49.65%)>GC_(2)(40.66%)>GC_(3)(29.79%),表明其叶绿体基因组密码子末位碱基偏好以A和U结尾;叶绿体基因组中大部分编码基因的ENC值>45;可推断出其密码子的偏性较弱。GC_(12)和GC_(3)的相关系数和回归系数分别为-0.208和-0.206,相关性不显著;ENC频数比值分布在-0.05~0.05间的有21个,这部分基因密码子偏好性主要受突变的影响;云南油杉叶绿体基因组中大部分基因分布在PR2平面图的右下方,即T>A、G>C;说明在云南油杉叶绿体基因组密码子使用模式上,其偏好性更多地受到选择影响,同时亦受到突变因素的影响。对应性分析发现,第1轴存在16.57%的差异,为主要影响因素,与ENC、GC_(3)相关系数为0.097、0.142,均无显著相关关系。最终UUA、CUU、AUU等15个密码子被确定为云南油杉叶绿体基因组的最优密码子。【结论】云南油杉叶绿体基因组密码子末位碱基偏好以A和U结尾,其密码子偏好性在受到选择影响的同时亦受到突变因素的影响。该结果可为今后开展云南油杉叶绿体基因工程、遗传多样性分析、种源鉴定等研究提供参考依据,同时也为油杉属叶绿体基因组进化机制研究提供理论基础。展开更多
基金funded by the Major Program for Basic Research Project of Yunnan Province,China,grant number 202101BC070002the Special Foundation for National Science and Technology Basic Resources Investigation of China,grant number 2019FY202300.
文摘Relict subtropical coniferous forests in China face severe fragmentation,resulting in declining populations,and some are under significant threat from invasive alien species.Despite the crucial importance of understanding forest dynamics,knowledge gaps persist,particularly regarding the impact of invasive plants on vulnerable natives like Keteleeria evelyniana.In this study,we investigated the impact of invasive plants on the regeneration of forests dominated by K.evelyniana,a subtropical relict species in southwestern China.For this purpose,we characterized forest dynamics of 160 forest plots featuring K.evelyniana as the primary dominant species and determined whether the presence of invasive plants was correlated with regeneration of K.evelyniana.We identified four distinct forest types in which K.evelyniana was dominant.We found that radial growth of K.evelyniana trees is faster in younger ageclasses today than it was for older trees at the same age.The population structure of K.evelyniana in each forest type exhibited a multimodal age-class distribution.However,three forest types lacked established saplings younger than 10 years old,a situation attributed to the dense coverage of the invasive alien Ageratina adenophora.This invasive species resulted in a reduction of understory species diversity.Additionally,our analysis uncovered a significant negative correlation in phylogenetic relatedness(net relatedness index)between native and invasive alien plant species in eastern Yunnan.This suggests closely related invasive species face heightened competition,hindering successful invasion.Taken together,our findings indicate that successful establishment and habitat restoration of K.evelyniana seedling/saplings require effective measures to control invasive plants.
文摘本文报道了新发现的一种病害——油杉枝瘤病,它是云南省中部云南油杉林内常见的一种重要病害,由王氏油杉盘针孢(Libertella wangii Ren et Zhou)所引起。受害林木在枝条上形成肿瘤,幼树主干上也有发生。肿瘤略呈球形,常包围枝条,大的肿瘤直径可达20cm。病原菌菌丝体在肿瘤表皮下形成分生孢子盘,成熟时表皮开裂,遇潮湿天气,从表皮裂隙中逸出橙色卷须状分生孢子角,分生孢子籍雨滴飞溅和气流传播。从嫩枝顶芽侵入。受害幼树应加以清除,必要时可在春末夏初喷撒杀菌剂以保护幼树。
文摘【目的】为了解云南油杉叶绿体基因密码子的偏好性使用模式。以云南油杉叶绿体基因组密码子为研究对象,筛选出41条蛋白编码序列,进行密码子偏好性分析,进一步揭示密码子组成特点及影响密码子偏好的因素,确定其最优密码子,为云南油杉开展叶绿体基因工程提供理论依据。【方法】利用Codon W 1.4.2和CUSP在线软件对云南油杉叶绿体基因密码子进行了中性绘图分析、ENC-plot、PR2-plot分析和对应性分析,分析密码子偏好性的影响因素,并从中得到最优密码子。【结果】云南油杉叶绿体基因组密码子不同位置上的GC含量依次是GC_(1)(49.65%)>GC_(2)(40.66%)>GC_(3)(29.79%),表明其叶绿体基因组密码子末位碱基偏好以A和U结尾;叶绿体基因组中大部分编码基因的ENC值>45;可推断出其密码子的偏性较弱。GC_(12)和GC_(3)的相关系数和回归系数分别为-0.208和-0.206,相关性不显著;ENC频数比值分布在-0.05~0.05间的有21个,这部分基因密码子偏好性主要受突变的影响;云南油杉叶绿体基因组中大部分基因分布在PR2平面图的右下方,即T>A、G>C;说明在云南油杉叶绿体基因组密码子使用模式上,其偏好性更多地受到选择影响,同时亦受到突变因素的影响。对应性分析发现,第1轴存在16.57%的差异,为主要影响因素,与ENC、GC_(3)相关系数为0.097、0.142,均无显著相关关系。最终UUA、CUU、AUU等15个密码子被确定为云南油杉叶绿体基因组的最优密码子。【结论】云南油杉叶绿体基因组密码子末位碱基偏好以A和U结尾,其密码子偏好性在受到选择影响的同时亦受到突变因素的影响。该结果可为今后开展云南油杉叶绿体基因工程、遗传多样性分析、种源鉴定等研究提供参考依据,同时也为油杉属叶绿体基因组进化机制研究提供理论基础。
