Beijing Biodiversity Conservation Research Center, Beijing, China.
Beijing Gardening and Greening Bureau, Beijing, China.
PLoS One. 2020 Jun 24;15(6):e0220598. doi: 10.1371/journal.pone.0220598. eCollection 2020.
Roof greening is an important national policy for maintaining the hydrological balance in China; however, plant growth is limited by drought stress. This study aims to identify strong drought resistant plant species for roof greening from ten common species: Paeonia lactiflora, Hemerocallis dumortieri, Meehania urticifolia, Iris lactea var. chinensis, Hylotelephium erythrostictum, Sedum lineare, Iris germanica, Cosmos bipinnata, Hosta plantaginea, and Dianthus barbatus. By controlling the soil relative water content (RWC), we designed three treatments: moderate drought stress (40±2% < RWC < 45±2%), severe drought stress (RWC < 30±2%) and well-watered control (RWC > 75±2%). After the seedlings were provided different levels of water, their membrane permeability (MP), chlorophyll concentration (Chl), and superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX) activity were measured. Finally, the membership function method was used to assess the drought resistance of these species. The results showed that C. bipinnata and M. urticifolia were not suitable for moderate or severe drought stress and did not survive. The other species presented variations in physiological and biochemical parameters. The MP of He. dumortieri, I. lactea and Ho. plantaginea showed minor changes between the well-watered control and drought stress. Most of the species showed reduced SOD activity under moderate drought stress but increased activity under severe stress. All of the plant species showed decreases in the protective enzymes POD and APX with increasing drought stress. The membership function method was applied to calculate the plant species' drought resistance, and the following order of priority of the roof-greening plant species was suggested: He. dumortieri > I. germanica > I. lactea > D. barbatus > Hy. erythrostictum > S. lineare > Ho. plantaginea > P. lactiflora.
屋顶绿化是中国维持水文平衡的重要国策；然而，植物的生长受到干旱胁迫的限制。本研究旨在从十种常见物种中确定适合屋顶绿化的强抗旱植物物种：牡丹、萱草、糯米条、中国菫菜、红景天、佛甲草、德国鸢尾、波斯菊、玉簪、和矮牵牛。通过控制土壤相对含水量（RWC），我们设计了三种处理：中度干旱胁迫（40±2%<RWC<45±2%）、重度干旱胁迫（RWC<30±2%）和充分浇水对照（RWC>75±2%）。在幼苗接受不同水平的水分后，测量其膜透性（MP）、叶绿素浓度（Chl）和超氧化物歧化酶（SOD）、过氧化物酶（POD）和抗坏血酸过氧化物酶（APX）活性。最后，采用隶属函数法评估这些物种的抗旱性。结果表明，C. bipinnata 和 M. urticifolia 不适合中度或重度干旱胁迫，无法存活。其他物种的生理生化参数也存在变化。在充分浇水和干旱胁迫下，He. dumortieri、I. lactea 和 Ho. plantaginea 的 MP 变化较小。大多数物种在中度干旱胁迫下 SOD 活性降低，但在重度胁迫下活性增加。所有植物物种的保护酶 POD 和 APX 活性随干旱胁迫的增加而降低。采用隶属函数法计算植物物种的抗旱性，建议优先选择以下屋顶绿化植物物种：He. dumortieri>I. germanica>I. lactea>D.barbatus>Hy. erythrostictum>S. lineare>Ho. plantaginea>P. lactiflora。
