土壤pH对活血丹生理特性及其药材品质的影响

为确定活血丹适宜种植区、完善活血丹种植技术、保障药材品质,以野生活血丹扦插苗为试验材料,用外源NaOH和H_2SO_4调节土壤pH,通过盆栽试验,研究不同土壤pH(4.5、5.5、6.5、7.5、8.5、9.5)条件下,活血丹植株生长、生理特性及其药材品质差异。结果表明:活血丹在pH 4.5～8.5能正常生长,在pH 9.5土壤中不能存活;在pH 4.5～8.5范围内,活血丹生长指标包括叶长、叶宽、节间距、节间数、茎长以及干物质积累量均呈先增后降的趋势,在pH 6.5达到峰值;活血丹叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性及叶绿素含量先增后降,可溶性糖、可溶性蛋白、游离氨基酸、丙二醛含量先降后增;活血丹药材醇溶性浸出物含量均大于250mg/g,符合药典标准;活血丹药材总黄酮、齐墩果酸和熊果酸含量变化趋势与生长指标一致,峰值出现在pH 6.5时,分别为15.73、0.71和2.87 mg/g;绿原酸和咖啡酸含量在pH 6.5～8.5之间无显著差异,整体高于其他pH处理;迷迭香酸含量在pH 7.5最高,为2.26 mg/g。土壤pH对活血丹生长、生理特性及其药材品质影响显著,中性或微酸性土壤利于活血丹的生长及其药材品质形成。

Effects of Soil pH on Physiological Characteristics and Medicinal Qualities of G . longituba

In order to determine the suitable cultivation area, improve the cultivation technology and guarantee the medicinal quality of G . longituba, the effects of soil pH (4.5, 5.5, 6.5, 7.5, 8.5 and 9.5) on growth, physiological characteristics and medicinal quality of G . longituba were studied with exogenous NaOH and H₂SO₄ as pH regulators. The results showed that G . longituba could grow normally in soil with pH from 4.5 to 8.5, but could not survive in soil with pH 9.5. The growth indicators of G . longituba including leaf length, leaf width, pitch interval, internode number, stem length and dry matter accumulation increased initially and then decreased when soil pH varied from 4.5 to 8.5, peaking at pH 6.5. The activities of SOD, POD, CAT and the content of chlorophyll in G . longituba leaves were first increased and then decreased, while the contents of soluble sugar, soluble protein, free amino acid and malondialdehyde in G . longituba leaves were reduced initially, and then increased. The contents of ethanol-soluble extractives were greater than 250 mg/g, conforming to the quality criterion in Chinese Pharmacopoeia 2015. The variation trend of total flavonoids, oleanolic acid and ursolic acid contents of G . longituba were similar to those of growth indexes; the highest contents of total flavone, oleanolic acid and ursolic acid were appeared in pH 6.5, with the contents of 15.73, 0.71 and 2.87 mg/g, respectively. The contents of chlorogenic acid or caffeic acid in pH 6.5, 7.5 and 8.5 treatments showed no significant difference, but generally higher than other treatments. The highest content of rosmarinic acid (2.26 mg/g) was observed in pH 7.5 treatment. It is concluded that soil pH has significant influence on growth, physiological characteristics and medicinal quality of G . longituba, and neutral or slightly acidic soil is conducive to the growth and the medicinal quality of G . longituba.