平茬高度对香椿生长及其光合特性和非结构性碳水化合物含量的影响

该研究以4年生香椿为试验材料,设置平茬20 cm(T_(1))、50 cm(T_(2))、80 cm(T_(3))和不平茬(CK)4种处理,观测其萌枝和叶片生长情况,以及叶片的气体交换参数、光合色素含量、非结构性碳水化合物(NSC)含量的变化,分析不同平茬高度的生长生理响应差异,以明确平茬措施下香椿植株更新复壮再生的生理机制。结果表明:(1)平茬能够显著提高香椿的萌枝能力,促进侧枝和叶片生长,其萌枝数、侧枝长度在T_(3)处理下最高,成枝数、叶长、叶宽、叶面积及侧枝粗度在T_(2)处理下达到最大值。(2)随着平茬高度的增加,香椿叶片净光合速率、蒸腾速率、气孔导度和水分利用效率均先升后降,并在T_(2)处理达到最大,较CK分别显著提高了17.33%、10.00%、13.51%和6.98%;平茬也提高了叶片光合色素含量,叶绿素a、叶绿素b、总叶绿素含量和类胡萝卜素含量在T_(2)处理下分别比CK显著提高了18.34%、27.07%、21.11%和23.05%。(3)不同平茬高度处理下,香椿叶、枝、根各器官中可溶性糖、淀粉和NSC含量均高于CK,且T_(2)和T_(3)处理增幅均达到显著水平;平茬处理与未平茬处理下香椿叶、枝、根不同器官中可溶性糖、淀粉和NSC含量分配规律一致,NSC含量表现为叶>根>枝。研究发现,平茬能够通过提高叶片光合色素含量和光合气体交换参数来促进香椿的光合能力,并通过优先储存策略促进不同器官中非结构性碳水化合物的积累和分配来适应平茬作业带来的影响,调控香椿萌枝发生及生长,并以平茬50 cm香椿更新恢复生长和光合能力最佳。

Constructing an assessment index system for strategic risk management in coal science and technology enterprises

Coal occupies a dominant position in China's national economy and is an essential energy source for future industrial development.To inform the efficient and sustainable development of the coal industry,this paper analyzes the sources of strategic risk for coal science and technology enterprises using 3 firstclass indicators,10 second-level indicators,and 37 observation points established through the existing research literature and experience.Moreover,in accordance to the obtained initial index data,the selected indicators have been tested and screened using reliability and membership degree analyses to remove redundant variables,avoid juxtaposition of risk factors at different levels,and reduce the influence of some tiny risk factors for enterprise strategic risk.Then,factor analysis of external environment factor sub-scale was carried out.Factors are extracted according to a standard characteristic value greater than 1.Variables with high coefficients are classified into one factor category;and finally,3 first-class indicators,8 second-level indicators,and 37 observation points are reconstructed.