Department of Biology, University of Trnava, Priemyselná 4, 918 43, Trnava, Slovak Republic.
Department of Plant Physiology and Biophysics, Institute of Biological Science, Maria Curie-Skłodowska University, 20-033, Lublin, Poland.
Protoplasma. 2020 Mar;257(2):439-447. doi: 10.1007/s00709-019-01448-1. Epub 2019 Nov 20.
Impact of various nitrate concentrations (14.12 mM, 3.53 mM, no nitrate) or ammonium presence (14.12 mM) on physiological and metabolic changes in Hypericum perforatum after 14 days of cultivation was monitored. Nitrate deficiency suppressed growth of shoots but stimulated root growth while ammonium suppressed root growth: concomitant changes of ascorbic acid and glutathione supported these growth changes, e.g., unaltered level in roots under nitrate deficiency but depleted in ammonium treatment. Soluble proteins and water content were more suppressed by nitrate deficiency but total ROS, nitric oxide formation, and antioxidative enzyme activities (APX and SOD) indicate higher sensitivity of plants to ammonium. Though both extreme treatments (NO deficiency or ammonium) stimulated accumulation of total soluble phenols and affected PAL activity (in comparison with full or 1/4× nitrate dose), major phenols (chlorogenic acid and three flavonoids) were elevated mainly by NO deficiency. At the level of specific metabolites, NO deficiency had stimulatory impact on pseudohypericin (but not hypericin) content while hyperforin decreased. Expression of earlier putative gene of hypericin biosynthesis (hyp-1) showed rather partial correlation with pseudohypericin amount. Data indicate that depletion of NO is useful to obtain Hypericum plants with higher amount of health-positive secondary metabolites.
研究了 14 天后，不同硝酸盐浓度（14.12 mM、3.53 mM、无硝酸盐）或铵态氮存在（14.12 mM）对贯叶连翘生理和代谢变化的影响。硝酸盐缺乏抑制了芽的生长，但刺激了根的生长，而铵态氮抑制了根的生长：抗坏血酸和谷胱甘肽的伴随变化支持了这些生长变化，例如，硝酸盐缺乏下根中的水平不变，但在铵处理中耗尽。可溶性蛋白和含水量受硝酸盐缺乏的抑制更为明显，但总 ROS、一氧化氮形成和抗氧化酶活性（APX 和 SOD）表明植物对铵的敏感性更高。尽管两种极端处理（NO 缺乏或铵）都刺激了总可溶性酚的积累，并影响了 PAL 活性（与全或 1/4×硝酸盐剂量相比），但主要的酚类物质（绿原酸和三种类黄酮）主要是由 NO 缺乏引起的。在特定代谢物水平上，NO 缺乏对伪贯叶连翘素（而不是贯叶连翘素）的含量有刺激作用，而 hyperforin 则减少。早期假贯叶连翘素生物合成的假定基因（hyp-1）的表达与伪贯叶连翘素的含量呈部分相关。数据表明，耗尽 NO 有利于获得含有更高数量有益健康的次生代谢物的贯叶连翘植物。
