Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Gatton, Queensland, 4343, Australia.
Punjab Agricultural University, Ludhiana, 141 004, India.
Sci Rep. 2018 Nov 20;8(1):17103. doi: 10.1038/s41598-018-35574-2.
Brassica tournefortii is an important broadleaf weed of the winter season in the northern grain region of Australia. Knowledge of germination ecology of this weed would help in implementing effective weed control programs. A series of experiments were conducted to study the germination and dormancy behavior of four biotypes of B. tournefortii seeds, biotypes A (collected from barley crop), B (barley fence lines), C (chickpea crop), and D (chickpea fence lines), collected from the St George region of Queensland. The aim of this research was to determine the effectiveness of various methods on the seed dormancy release of B. tournefortii. Water, potassium nitrate and a soil extract did not release dormancy in B. tournefortii seeds (biotype A) at 20/10 °C in the light/dark regime. Cold stratification (5 °C) also did not improve germination. However, gibberellic acid (GA; 100-300 mg kg) stimulated germination (>88%). Germination also improved when seeds were immersed in sodium hypochlorite (NaOCl; 42 g L) for 10 minutes and the effect was more pronounced under the complete dark environment (89% germination at a day/night temperature of 20/10 °C). The NaOCl treatment makes seeds more porous and decreases sensitivity to light. Another experiment in light/dark conducted at 25/15 °C with two biotypes (A and D) showed that, without NaOCl treatment, biotype A was more sensitive to light (29% germination) as compared to biotype D (92% germination). Our results suggest that dormancy in B. tournefortii seeds can be broken by the combination of NaOCl (10 min) and a dark environment. A day/night temperature of 25/15 °C was found best for optimum germination (>87%) for all the biotypes (A-D) when incubated in dark after treating with NaOCl. This research indicated a high degree of variability in germination responses for various biotypes of B. tournefortii seeds to various sets of conditions, which may be due to metabolic changes in response to maternal environments or genetically controlled mechanisms. Information gained from this study will be important in developing a better understanding of the dormancy behavior of B. tournefortii seeds in response to tillage systems or maternal environments that could influence the weed seed bank in the soil and therefore help in designing suitable weed management programs.
甘蓝型油菜是澳大利亚北部粮食产区冬季的一种重要阔叶杂草。了解这种杂草的萌发生态学知识有助于实施有效的杂草控制计划。本研究进行了一系列实验，以研究来自昆士兰州圣乔治地区的甘蓝型油菜四个生物型（A 型：从大麦作物中收集，B 型：大麦围栏线，C 型：鹰嘴豆作物，D 型：鹰嘴豆围栏线）种子的萌发和休眠行为。本研究的目的是确定各种方法对打破甘蓝型油菜种子休眠的效果。在光照/黑暗条件下，20/10°C 时，水、硝酸钾和土壤浸提液对甘蓝型油菜种子（生物型 A）的休眠没有释放作用。低温层积（5°C）也不能提高发芽率。然而，赤霉素（GA；100-300mgkg）刺激发芽（>88%）。将种子浸泡在次氯酸钠（NaOCl；42g/L）中 10 分钟也能提高发芽率，在完全黑暗的环境下效果更为显著（20/10°C 时的日/夜温度下，发芽率为 89%）。NaOCl 处理使种子更具多孔性，并降低对光的敏感性。在光照/黑暗条件下，在 25/15°C 下进行的另一项实验表明，对于两个生物型（A 和 D），没有 NaOCl 处理时，生物型 A 对光更敏感（29%发芽），而生物型 D 则相反（92%发芽）。我们的研究结果表明，甘蓝型油菜种子的休眠可以通过 NaOCl（10 分钟）和黑暗环境的组合打破。在黑暗中用 NaOCl 处理后，所有生物型（A-D）在 25/15°C 的日/夜温度下的最佳发芽率（>87%）。本研究表明，甘蓝型油菜不同生物型种子对不同条件的萌发反应存在高度的可变性，这可能是由于对母体环境的代谢变化或遗传控制机制。从这项研究中获得的信息对于更好地了解甘蓝型油菜种子对耕作系统或母体环境的休眠行为将是重要的，这可能会影响土壤中的杂草种子库，从而有助于设计合适的杂草管理计划。
