Ji Peng, Chan Yuan, Lu Mingyue, Zhai Ying, Lv Hailiang, Wang Hongyi, Hasnslin Hans Martin
College of Horticulture & Landscape Architecture, Heilongjiang Bayi Agricultural University, Heilongjiang, 163319, China.
Department of Urban Greening and Environmental Engineering, Norwegian Institute of Bioeconomy Research (NIBIO), Ås, Norway.
Heliyon. 2024 Aug 10;10(16):e36077. doi: 10.1016/j.heliyon.2024.e36077. eCollection 2024 Aug 30.
The impact of winter moisture on root metabolism and root integrity has potential consequences for the geographical distribution of drought-adapted succulent species and for their long-term performance on green roofs. The interacting effects of soil characteristics and precipitation frequency on root mortality under winter conditions and the potential to grow new roots in spring were evaluated for six species under controlled conditions.
To test for the impact of soil moisture during winter on root regrowth potential in six Sedum species, we used a combination of two substrates with differing water-holding capacity and four contrasting watering regimes. Specially, for the fine and coarse substrates, total pore volume was 42 and 46 %, respectively, and maximum water-holding capacity (i.e. field capacity) was 0.50 and 0.33 kg water per L, respectively. The four watering treatments involved overhead watering to runoff (approx. 10 mm): once every second week, once a week, three times per week and three times per week with 1 cm standing water in trays from January to March 2019.
It was found that winter soil moisture had no major impact on root mortality or root regrowth potential in spring. Root mortality was not affected by watering frequency and regrowth potential showed no directional response to increased watering frequency, although species-specific responses were involved. Root diameter did not differ between the substrates, but there were some differences between the species. had on average the thickest roots (0.17 mm), followed by , and (0.15-0.16 mm), while and had the thinnest roots (0.12-0.13 mm). Moreover, effects of watering frequency on root mortality and regrowth potential were not influenced by soil water-holding capacity across species. We concluded that winter soil moisture had no negative effects on root performance within the range of treatments tested here.
Root response to transient waterlogging or moist but unsaturated soil may not be an important mechanism for determining the survival and distribution of temperate species during winter.
冬季水分对根系代谢和根系完整性的影响，对于适应干旱的肉质植物物种的地理分布及其在绿色屋顶上的长期表现具有潜在影响。在可控条件下，评估了六种植物在冬季条件下土壤特性和降水频率对根系死亡率的交互作用，以及春季新根生长的潜力。
为测试冬季土壤水分对六种景天属植物根系再生潜力的影响，我们将两种持水能力不同的基质与四种不同的浇水方式相结合。具体而言，细基质和粗基质的总孔隙体积分别为42%和46%，最大持水量（即田间持水量）分别为每升0.50千克水和0.33千克水。四种浇水处理包括顶部浇水至径流（约10毫米）：2019年1月至3月期间，每隔一周一次、每周一次、每周三次以及每周三次并在托盘中保持1厘米积水。
发现冬季土壤水分对根系死亡率或春季根系再生潜力没有重大影响。根系死亡率不受浇水频率的影响，尽管存在物种特异性反应，但再生潜力对浇水频率增加没有定向反应。不同基质间根系直径没有差异，但不同物种间存在一些差异。平均根系最粗（0.17毫米），其次是、和（0.15 - 0.16毫米），而和根系最细（0.12 - 0.13毫米）。此外，浇水频率对根系死亡率和再生潜力的影响不受物种间土壤持水能力的影响。我们得出结论，在此测试的处理范围内，冬季土壤水分对根系性能没有负面影响。
根系对短暂涝渍或潮湿但不饱和土壤的反应，可能不是决定温带景天属物种冬季存活和分布的重要机制。
