Inheritance of morphological traits of periwinkle mutants with modified contents and yields of leaf and root alkaloids

Periwinkle Catharanthus roseus is a medicinally important plant producing anticancer and antihypertension alkaloids. Two mutants, one dwarf and one semidwarf and both, with a high alkaloid content in the roots and one mutant with a wavy leaf margin and a high alkaloid content in its leaves were obtained after induced chemical mutagenesis with ethyl methane sulphonate and N-nitroso-N-ethylurea in the variety ‘Nirmal’, which is resistant to dieback disease. These mutants were evaluated in the M₃ and M₄ generations. The dwarf and semidwarf mutants differed from the parental variety for many morphological characters, while the mutant with the wavy leaf margin differed mainly in leaf size and leaf thickness. Although both dwarf and semidwarf mutants showed a significantly higher alkaloid content in their roots in both generations, only the semidwarf mutant gave a significantly higher (23%) root alkaloid yield than the parental variety. The mutant with the wavy leaf margin showed a significantly higher alkaloid content in the leaves in both the M₃ and M₄ generations and also had a significantly higher (21%) leaf alkaloid yield than the parental variety. All three mutants were found to be controlled by monogenic recessive genes; the genes for ‘dwarfness’ and ‘semidwarfness’ were allelic to each other, with the allele for semidwarfness being dominant over the allele for dwarfness. The gene for the wavy leaf margin was inherited independently of the genes for dwarfness and semidwarfness.     

动态水环境容量研究——以潇河流域为例

传统的水环境容量以90%设计枯水流量为计算条件,存在水文计算条件单一、水环境容量不易管控等缺点。考虑河道流量与入河污染物影响下的水环境容量逐月变化,提出了基于水文过程与污染源变化条件下的动态水环境容量与入河污染管控计算方法。以山西潇河流域晋中段为例,计算了研究流域两水功能区的逐月水环境容量及其余量,运用MIKE11模型计算了逐月允许的动态入河污染负荷。研究结果表明:(1)2019年水功能区A的COD和氨氮水环境容量阈值分别为138.37~216.54 t和6.38~14.19 t,7-10月水环境容量较大;水功能区B的COD和氨氮水环境容量阈值分别为417.67~821.05 t和9.32~29.49 t,5-8月份水环境容量较小。(2)在满足水功能区目标水质的基础上,2019年水功能区A允许的入河负荷均大于现状入河量,汛期COD和氨氮容量余量较多;水功能区B在1月、2月应削减氨氮0.003、0.086 t;削减COD 0.05、0.143 t,4-7月份允许的污染负荷大于实际入河量,余量较多。计算的动态水环境容量能够客观反映变化水文条件下的水环境容量及其余量实际,给出了满足河道水质目标前提下的入河污染物允许阈值,为流域水环境保护与管理提供重要参考和新思路。     

基于Markov-PLUS模型的柴北缘土地利用变化及模拟分析

以柴达木盆地北缘为研究区域，分析近30 a柴北缘土地利用时空变化，可为区域生态环境保护 、土地利用方式优化提出建议。基于1990、2000、2010、2020年4期Landsat影像数据，获取土地利用空间分布数据，借助转移矩阵、重心模型对近30 a柴北缘土地利用时空变化及驱动力计算分析，利用Markov-PLUS复合模型对2040年柴北缘土地利用变化进行预测和模拟。结果表明:1)未利用地、林地、水域是柴北缘的主要用地类型。近30 a耕地面积缓慢增加，重心向西南方向移动，建设用地面积增长迅速，林地、草地、水域面积总体呈上升趋势，重心都向西北方向移动，未利用地面积持续下降。2)使用FLUS模型与Markov-PLUS模型分别预测柴北缘2020年土地利用情况并对比分析，Markov-PLUS模型比FLUS模型的模拟准确性更高。3)2040年多情景模拟结果表明，柴北缘土地利用整体格局一致性较高，城镇发展和耕地保护情景下均会挤占林地、草地，对可持续发展造成威胁，在区域生态安全建设中应加以重视。PLUS模型与Markov模型相结合，实现了对未来土地利用斑块级的精准预测，可为未来提升柴北缘生态退化整治效果、城镇开发边界与生态保护红线的制定与规划等提供科学决策参考。     

PM2.5 reduction capacities and their relation to morphological and physiological traits in 13 landscaping tree species

Fine particulate matter (PM_2.5) is emerging as a serious environmental problem worldwide with the increase in anthropogenic emission sources, such as fossil fuels, transportation, and industries. In urban areas, where industrial complexes and human activities are concentrated, PM_2.5 poses a threat to human health. Recently, because of their ability to reduce PM_2.5, the introduction of landscaping trees as an environment-friendly solution has become popular; however, there remains a lack of research on the selection of species and their management. In this study, we quantified and compared the PM_2.5 reduction capacities of 13 major landscaping tree species and analyzed their relationship with the morphological and physiological characteristics of each species. The results showed that the amount of PM_2.5 reduction per leaf area differed among species and was the highest in Ginkgo biloba (28 165 ± 5353 # cm⁻² min⁻¹) and the lowest in Pinus strobus (1602 ± 186 # cm⁻² min⁻¹). Moreover, PM_2.5 reduction by the broadleaf species (18 802 ± 1638 # cm⁻² min⁻¹) was approximately 8.6-fold higher than that of the needleleaf species (2194 ± 307 # cm⁻² min⁻¹). Correlation analysis revealed that differences in PM_2.5 reduction were explained by differences in specific leaf area between species (P = 0.004) and by the length of margin per leaf area among individual trees (P < 0.05). Additionally, reduction in PM_2.5 correlated with photosynthetic properties such as maximum assimilation and carboxylation rates (P < 0.001), indicating that PM_2.5 is reduced not only by physical adsorption but also by physiological processes. These findings emphasize that for effective reduction in PM_2.5 using landscaping trees, comprehensive consideration of the morphological and physiological characteristics of the species is essential during species selection, and that continuous management is also necessary to maintain the active physiological conditions of the trees.