Government Reclamation Research Station, Mian Channu, Pakistan.
Department of Plant Breeding and Genetics, Ghazi University, D. G. Khan, Pakistan.
PLoS One. 2020 Oct 30;15(10):e0241601. doi: 10.1371/journal.pone.0241601. eCollection 2020.
Xanthium strumarium L. (Common cocklebur) is a noxious weed prevailing in different ecosystems around the world. It incurs significant yield and economic losses in different cropping systems globally. Successful management of any weed species depends on sound knowledge of seed germination biology. However, detailed knowledge on seed germination biology of the species is missing. Therefore, we investigated the impact of different environmental factors on seed germination and seed burial depths on seedling emergence of two X. strumarium populations. The impact of different sorghum mulch doses (0-10 t ha-1) on seedling emergence of the tested populations was also explored. Seed germination was evaluated under different photoperiods (0, 12 and 24), constant temperatures (0-50°C with 5°C stepwise rise), and different levels of pH (3-12), salinity (0-600 mM) and osmotic potential (0 to -1.6 MPa). Seedling emergence was observed for seeds buried at different depths (0-15 cm). Seeds of both populations proved non-photoblastic; however, higher germination was recorded under 12-hour photoperiod. The seeds germinated under a wide range of constant temperatures (10-45°C), pH (4-10), osmotic potentials (0 to -0.8 MPa) and salinity levels (0-400 mM NaCl). However, the highest germination was observed under 30-31°C temperature and neutral pH (7.51-7.52). Seeds were able to withstand 400 mM salinity and -1.00 MPa osmotic potential. Seedling emergence was initially improved with increasing burial depth and then a sharp decline was noted for the seeds buried >3 cm depth. Most of the seeds of both populations did not emerge from >8 cm depth. Different sorghum mulch doses linearly suppressed seedling emergence of tested populations, and 5.83-5.89 t ha-1 mulch application suppressed 50% of seedling emergence. Seedling emergence was completely retarded with 8 t ha-1 sorghum mulch. The tested populations germinated under diverse environmental circumstances indicating that the species can become troublesome in marginal habitats and cropped lands. Deep burial of seeds and application of sorghum mulches suppressed seedling emergence. Thus, deep burial followed by shallow tillage and application of sorghum mulches could be used as a successful strategy to manage the species in agricultural fields. Nonetheless, management strategies must be developed to control the species in other habitats.
苍耳（Xanthium strumarium L.）是一种世界性的有害杂草，普遍存在于不同的生态系统中。它在全球不同的作物系统中造成了显著的产量和经济损失。任何杂草物种的成功管理都依赖于对种子萌发生物学的充分了解。然而，该物种的种子萌发生物学的详细知识仍然缺乏。因此，我们研究了不同环境因素对两种苍耳种群种子萌发的影响，以及种子埋藏深度对幼苗出土的影响。还探讨了不同高粱覆盖剂量（0-10 t ha-1）对试验种群幼苗出土的影响。在不同的光周期（0、12 和 24 小时）、恒定温度（0-50°C，温度逐步升高 5°C）和不同的 pH 值（3-12）、盐度（0-600 mM）和渗透势（0 至-1.6 MPa）下评估了种子萌发情况。观察了埋藏在不同深度（0-15 cm）的种子的幼苗出土情况。两个种群的种子均表现出非光依赖性，但在 12 小时光周期下的萌发率更高。种子在很宽的温度范围（10-45°C）、pH 值（4-10）、渗透压（0 至-0.8 MPa）和盐度水平（0-400 mM NaCl）下均能萌发。然而，在 30-31°C 的温度和中性 pH 值（7.51-7.52）下的萌发率最高。种子能够耐受 400 mM 的盐度和-1.00 MPa 的渗透势。随着埋藏深度的增加，幼苗出土率最初会提高，然后当种子埋藏深度超过 3 cm 时，出土率会急剧下降。两个种群的大部分种子都无法从超过 8 cm 的深度出土。不同高粱覆盖剂量对线形抑制了试验种群的幼苗出土，5.83-5.89 t ha-1 覆盖物的应用抑制了 50%的幼苗出土。8 t ha-1 高粱覆盖物完全延迟了幼苗出土。两个种群的种子在不同的环境条件下萌发，表明该物种在边缘生境和作物地中可能会成为一个麻烦。种子的深埋藏和高粱覆盖物的应用抑制了幼苗的出土。因此，深埋藏后进行浅层耕作，并应用高粱覆盖物，可能成为农业领域中成功管理该物种的策略。然而，必须制定管理策略来控制该物种在其他生境中的生长。
