Evaluation of bioherbicidal potential of Carica papaya leaves

Abstract Due to increased number of herbicide resistant weeds, it is needed to explore the allelopathic potential of plants as an alternative. The research was conducted to investigate allelopathic effects of Carica papaya L. leaf powder and aqueous extract on seeds as well as pre-germinated seeds of Avena fatua L., Helianthus annuus L., Rumex dentatus L., Zea mays L. and Triticum aestivum L. on filter paper and soil in Weed Management Program Laboratory, Department of Plant and Environmental Protection at PARC Institute of Advanced Studies in Agriculture, National Agriculture Research Centre, Islamabad, Pakistan. Germination percentage (%), radicle length (cm) and plumule length (cm) were parameters observed for ‘Plant leaf powder bioassay’ and ‘Aqueous extract method’. Most significant growth inhibition was observed in A. fatua seedlings in filter paper method. A. fatua radicle length was reduced by C. papaya aqueous extract (80%) and leaf powder (89%) bioassays. Plumule length was reduced under the influence of aqueous extract (57-73%) and powdered material (59-77%). The inhibitory effects on other test species were in sequence of H. annuus followed by Z. mays and R. dentatus. The aqueous extract showed non-significant effect on wheat seed germination, radicle and plumule growth. It is suggested that C. papaya aqueous extract can be used as source of weed management in wheat crop.

摘要 随着抗除草剂杂草种群数量不断增加，探索植物化感潜力作为杂草防控的替代方案已成为亟需开展的研究方向。本研究以巴基斯坦伊斯兰堡国家农业研究中心植物与环境保护系杂草管理项目实验室（隶属于巴基斯坦农业研究委员会（Pakistan Agricultural Research Council, PARC）农业高等研究院）为试验平台，探讨番木瓜（Carica papaya L.）叶粉及其水浸提液，对野燕麦（Avena fatua L.）、向日葵（Helianthus annuus L.）、齿果酸模（Rumex dentatus L.）、玉米（Zea mays L.）及普通小麦（Triticum aestivum L.）的种子与预萌发种子的化感作用，试验分别采用滤纸法与土壤法开展。本研究针对“叶片粉末生物测定法”与“水浸提液法”，测定了3项核心指标：发芽率（%）、胚根长度（cm）与胚芽长度（cm）。结果显示，滤纸法测定中，野燕麦幼苗的生长受抑制效果最为显著：番木瓜水浸提液与叶粉生物测定分别使野燕麦胚根长度降低80%与89%；水浸提液处理使胚芽长度降低57%~73%，粉末处理则使胚芽长度降低59%~77%。对其余供试物种的抑制效果依次为向日葵＞玉米＞齿果酸模。番木瓜水浸提液对小麦种子的发芽率、胚根及胚芽生长均无显著影响。研究表明，番木瓜水浸提液可作为小麦田杂草防控的潜在有效资源。