How light pollution can affect spring development of urban trees and shrubs

While artificial light at night (ALAN) is gaining more attention in view of its proven negative effect on animals, including humans, it remains a little-known matter when it comes to plants. Street lamps emit light that can be perceived by plants, and therefore disturb their natural photoperiod. In the present work we examine two different light treatments considered as low intensity (L-LP) and medium intensity (M-LP) light pollution (1 μmol·m⁻²·s⁻¹ and 30 μmol·m⁻²·s⁻¹ during the night, respectively) both comparable to different street lamps parameters (based on own field measurements). We have studied the influence of those LP treatments on the spring phenology and physiology of 4 tree species and 4 shrub species. The experiment involved species commonly used in European urban areas: Tilia tomentosa, Betula pendula, Fagus sylvatica, Acer campestre, Cornus alba, Lonicera pileata, Kerria japonica and Spiraea ×cinerea. All the investigated species were influenced by ALAN and developed buds faster than the control group. However, the changes were visible at different stages of bud development depending on species. The light pollution treatments resulted in a reduction of soluble sugars, measured in apical twigs of T. tomentosa, S. ×cinerea, K. japonica and A. campestre. In contrast, the soluble sugar content increased in branches of light-polluted L. pileata and C. alba when compared to the control group. These results prove, that light pollution affects the spring phenology and physiology of deciduous species. Long-term consequences of such reactions require more detailed studies.     

不同基质配比对乌桕容器苗矿质元素和非结构性碳水化合物的影响

为了探讨乌桕容器苗在不同基质配比下生长情况，通过分析各个指标的变化揭示其生长规律。以苗圃土、泥炭、珍珠岩为基质原料，按不同体积配比，研究不同基质配比对乌桕容器苗矿质元素浓度和非结构性碳水化合物浓度的影响，筛选适宜乌桕苗的基质类型。结果表明：(1)矿质元素方面，D1(90%泥炭+10%珍珠岩)全氮、全磷、全钾、全碳含量最高，分别为1.17%、0.46%、6.09 mg/g、16.47%,D2(70%泥炭+30%珍珠岩)次之。(2)非结构性碳水化合物方面，D1可溶性糖、淀粉浓度最高，分别为0.55%、2.54%,D2次之，CK(100%苗圃土)最低。综上所述，D1(90%泥炭+10%珍珠岩)基质最适宜乌桕容器苗的培育。     

不同施氮水平对桑树幼苗非结构性碳水化合物及其抗旱能力的影响

为研究施氮对干旱胁迫下桑树幼苗形态和非结构性碳水化合物(NSC)含量的影响，以‘云桑1号’幼苗为研究对象，在对照(D₀,土壤含水量约75%)和干旱(D₁,土壤含水量约30%)两种水分环境下分别设置0mmol/L(N₀)、12.5mmol/L(N₁)和25.0mmol/L(N₂)NH₄NO₃ 3种浓度的施氮处理，分析不同水氮条件下桑树幼苗的形态、生物量、可溶性糖、淀粉和NSC含量。结果显示：(1)干旱使桑树幼苗各器官中可溶性糖、淀粉、NSC含量显著增加。各氮素水平下叶中可溶性糖和NSC含量增量最高，达到82.27%～163.31%和70.61%～138.00%;根中淀粉含量增量最高，达到6.05%～31.75%。随着氮浓度升高，干旱胁迫下桑树幼苗各器官中的可溶性糖和NSC含量均呈先降后增的趋势。(2)干旱显著抑制桑树幼苗各器官的形态发育和生长，施氮则促进其地上部分的形态发育和生长，尤其是施氮12.5mmol/L水平缓解干旱下桑树幼苗地上...