African mustard (Brassica tournefortii Gouan) is a problematic winter annual weed in Australia. Germination ecology of B. tournefortii may change in response to the maternal environments or habitats in which the plants grow. A study was conducted to evaluate the effect of environmental factors on germination and emergence of four populations of B. tournefortii that were collected from different fields. Averaged over populations, germination was stimulated by dark and was higher at 25/15 C (92%) compared with 15/5 C (76%) and 35/25 C (45%). Averaged over light/dark regimes, at the lowest temperature regime (15/5 C), population A had higher germination than population D; however, at the highest temperature regime (35/25 C), population D had higher germination than population A. Populations B and C had higher germination in the temperature range of 25/15 C and 30/20 C compared with 15/5 C, 20/10 C, and 35/25 C. Seeds germinated at a wide range of alternating day/night temperatures (15/5 to 35/25 C), suggesting that seeds can germinate throughout the year if other optimum conditions are available. Population A was more tolerant to water and salt stress than population D. The sodium chloride concentration and osmotic potential required to inhibit 50% germination of population A were 68 mM and −0.60 MPa, respectively. Averaged over populations, seeds placed at 1-cm soil depth had the highest emergence (54%), and burial depth of 8 cm resulted in 28% seedling emergence. Averaged over populations, wheat residue retention at 6,000 kg ha−1 resulted in greater seedling emergence than the residue amount of 1,000 kg ha−1. The results suggest that B. tournefortii will be favored in no-till systems and that the seedbank of B. tournefortii could be managed by tillage regimes that bury its seeds below 8-cm depths and restrict seedling emergence and growth of new plants.

中文翻译：

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澳大利亚东部地区四种非洲芥菜（Brassica tournefortii Gouan）种群的萌发生态学

非洲芥末（芸薹属Gouan）是澳大利亚有问题的冬季一年生杂草。萌发生态B.tournefortii可能会随着植物生长的母体环境或栖息地而改变。进行了一项研究，以评估环境因素对四个种群发芽和出苗的影响。B.tournefortii从不同领域收集的。对种群进行平均，发芽受黑暗刺激，在 25/15 C (92%) 时高于 15/5 C (76%) 和 35/25 C (45%)。平均在光照/黑暗状态下，在最低温度状态（15/5 C）下，种群 A 的发芽率高于种群 D；然而，在最高温度条件下（35/25 C），种群 D 的发芽率高于种群 A。种群 B 和 C 在 25/15 C 和 30/20 C 的温度范围内的发芽率高于 15/5 C 、20/10 C 和 35/25 C。种子在很宽的昼夜交替温度（15/5 到 35/25 C）下发芽，这表明如果有其他最佳条件，种子可以全年发芽。种群 A 比种群 D 更能耐受水和盐胁迫。抑制 A 群 50% 萌发所需的氯化钠浓度和渗透势分别为 68 mM 和 -0.60 MPa。对种群进行平均，放置在 1 厘米土壤深度的种子出苗率最高（54%），而 8 厘米的埋深导致 28% 的出苗率。对种群进行平均，小麦残留量为 6,000 公斤公顷-1导致出苗量超过 1,000 公斤公顷的残留量-1. 结果表明B.tournefortii将在免耕系统中受到青睐，并且B.tournefortii可以通过将种子埋在 8 厘米以下并限制幼苗出现和新植物生长的耕作制度来管理。