Department of Landscape Ecology, Institute of Natural Resource Conservation, Kiel University, Kiel, Germany.
Plant Biol (Stuttg). 2024 Apr;26(3):437-445. doi: 10.1111/plb.13633. Epub 2024 Mar 2.
Roadside vegetation in Central Europe is mostly species-poor and dominated by a few grass species. Hemiparasitic plant species, including Rhinanthus spp., might effectively restrict grass growth, thereby making space for light-dependent herb species. Despite the significance of abiotic site conditions for plant establishment in general, their effects on Rhinanthus establishment are less well known. We investigated combined effects of water availability, litter amount and seed position within litter on Rhinanthus seedling emergence and growth. Two parallel greenhouse experiments were conducted with R. angustifolius and R. minor. In these, we tested the impact of 200 or 400 g litter·m with seeds sown beneath or on top of a litter layer under constantly humid or intermittently dry conditions on seedling emergence and biomass production of Rhinanthus. Presence of litter positively affected Rhinanthus seedling emergence when sown beneath the litter layer and reduced negative effects of water deficiency. Sowing beneath a litter layer increased seedling emergence by 157%, with similar effects at 200 and 400 g litter·m. Water level did not affect biomass production. Compared to R. minor, R. angustifolius had higher mean biomass, and its seedlings emerged earlier and in higher numbers. Our results indicate that Rhinanthus spp. react similarly to litter as non-hemiparasitic plant species from temperate grasslands. Litter presence positively influenced Rhinanthus seedling emergence and growth under intermittently dry conditions. Its hemiparasitic characteristics might reduce drought impacts on biomass production. To ensure seed contact with the soil surface, seeds should be sown when no litter is present, or mulching should occur post-sowing.
中欧的路边植被大多物种贫乏，以少数几种草为主。半寄生植物物种，包括米口袋属（ Rhinanthus ），可能会有效地限制草的生长，从而为喜光草本植物腾出空间。尽管非生物生境条件对植物的建立具有重要意义，但它们对半寄生植物建立的影响知之甚少。我们调查了水分可用性、凋落物量以及种子在凋落物中的位置对米口袋属幼苗出苗和生长的综合影响。进行了两个平行的温室实验，涉及宽叶米口袋（ R. angustifolius ）和米口袋（ R. minor ）。在这些实验中，我们测试了在持续湿润或间歇性干燥条件下，在 200 或 400g·m -2 凋落物下播种种子，以及在凋落物层下或顶部播种种子对米口袋属幼苗出苗和生物量产生的影响。当种子播种在凋落物层下时，凋落物的存在会积极影响米口袋属幼苗的出苗，并减少水分不足的负面影响。在凋落物层下播种可使幼苗出苗增加 157%，在 200 和 400g·m -2 凋落物下的效果相似。水位不影响生物量的产生。与米口袋（ R. minor ）相比，宽叶米口袋（ R. angustifolius ）具有更高的平均生物量，其幼苗更早出现且数量更多。我们的结果表明，米口袋属（ Rhinanthus ）对凋落物的反应与来自温带草原的非半寄生植物物种相似。在间歇性干燥条件下，凋落物的存在会积极影响米口袋属幼苗的出苗和生长。它的半寄生特性可能会减少干旱对生物量产生的影响。为了确保种子与土壤表面接触，在没有凋落物存在时播种，或者在播种后进行覆盖。
