The effect of different potassium concentrations and electrical conductivity on hydroponi-grown <i>Trachyandra divaricata</i>, as green vegetable

Wild leafy vegetables are commonly included in the diet of people in rural homesteads. Among various wild edible vegetables in South Africa, <i>Trachyandra divaricata</i> (Sandkool) is one of the most abundant but underutilized due to the dearth of literature on its cultivation and nutritional value. In the present study, the effect of potassium application and pruning on growth dynamics, mineral composition, and proximate and phytochemical content in <i>T. divaricata</i> were evaluated. Treatments consisted of three potassium concentrations (0.0072, 0.0144, and 0.0216 M) supplemented in the form of potassium sulphate (K₂SO₄) with four pruning levels (unpruned, 5, 10, and 15 cm) applied in each treatment. The potassium doses were added to the nutrient solution, while the control treatment was sustained and irrigated with nutrient solution only. The results revealed a significant increase in flower bud yield, height, total dry and wet weight of shoots and roots, as well as ash and neutral detergent fibre in plants irrigated with 0.0072 M of K₂SO₄ without pruning. Conversely, chlorophyll content and Ca were comparable among treatments, while the highest yield of Na, P, N, and Zn was recorded in treatment 100 mL of K₂SO₄ with 10 cm pruning. Likewise, the highest antioxidant value (Polyphenols, Flavonol and DPPH) was obtained from plants irrigated with 0.0072 M of K₂SO₄ with 10 cm pruning. Based on these findings, <i>T. divaricata</i> is a promising leafy vegetable as a minimum dose (0.0072 M) of K with moderate pruning optimised its productivity in terms of growth, biomass parameters, nutritional content, and antioxidant potential. Due to its rich nutritional value, the plant should be domesticated and studied further for its potential nutraceutical benefits

野生叶菜常作为乡村农户日常膳食的重要组成部分。在南非各类野生可食用蔬菜中，<i>Trachyandra divaricata</i>（Sandkool）是分布最为广泛的物种之一，但由于当前关于其栽培技术与营养价值的研究文献匮乏，该物种尚未得到充分开发利用。本研究以<i>T. divaricata</i>为研究对象，评估了钾肥施用与修剪处理对其生长动态、矿物元素组成、常规营养成分及植物化学物含量的影响。试验设置了三种钾肥浓度梯度（0.0072、0.0144、0.0216 M），均以硫酸钾（K₂SO₄）形式添加；同时设置四种修剪水平（不修剪、修剪至5 cm、10 cm、15 cm），每个钾肥浓度梯度均搭配全部四种修剪水平进行处理。钾肥药剂均添加于营养液中，对照组仅浇灌普通营养液，不施加钾肥。试验结果显示，施加0.0072 M硫酸钾且不进行修剪的处理组，其花蕾产量、植株高度、地上部与地下部总鲜重及干重，以及灰分与中性洗涤纤维含量均显著提升。与之相对的是，各处理组的叶绿素含量与钙元素水平无显著差异；而钠（Na）、磷（P）、氮（N）及锌（Zn）的最高产量出现在施加100 mL硫酸钾且修剪至10 cm的处理组中。同样地，抗氧化活性指标（多酚、黄酮醇及DPPH自由基清除率）的最高值出现在施加0.0072 M硫酸钾且修剪至10 cm的处理组植株中。基于上述试验结果，<i>T. divaricata</i>是一种极具开发潜力的叶用蔬菜：以最低剂量（0.0072 M）的钾肥配合适度修剪，可在生长指标、生物量参数、营养成分及抗氧化潜能等维度优化其生产性能。鉴于其丰富的营养价值，该物种应被驯化并开展进一步研究，以挖掘其作为功能性保健食品的潜在益处。