Diurnal changes of photosynthesis in panax ginseng and panax quinquefolium under different environmental conditions | 不同生境条件下人参、西洋参光合作用的日变化

Chino. 研究了不同生境条件下人参、西洋参光合特性的日变化.结果表明,弱光（10%透光率的荫棚）下人参、西洋参叶片的净光合速率（Pn）呈单峰曲线型变化,Pn的最大值在12：00―13：00时,9：00―11：00时和14：00―16：00时较低;适宜光强（20%-40%透光率的荫棚）下,9：00―11：00和12：00―13：00时为人参、西洋参Pn的高稳时期,14：00―16：00时后下降.强光（50%透光率荫棚）下,9：00―11：00时Pn最大,14：00―16：00时明显下降.1 d中人参、西洋参光合日下降率为10%-40%,弱光下生长的Pn较低,光合日下降率也低,随着生长期间光强的增加,Pn增加,光合日下降率也增加.叶片表观量子产额（AQY）以9：00―11：00时最高,中午略有下降,14：00―16：00时最低.栽培于干热地区（长春）的人参和西洋参Pn、AQY和气孔导度（Gs）的日下降率和水蒸气压亏缺（VPD）明显高于栽培于温凉多湿吉林省东部山区（辉南县）的人参和西洋参叶片.2个地区叶片的蒸腾作用（Tr）和水分利用效率（WUE）也有明显差异,长春地区生长的人参和西洋参9：00―11：00时的Tr高于14：00―16：00时；而辉南地区生长的人参和西洋参叶片1d中的Tr基本一致．在9：00―11：00时辉南地区的人参和西洋参叶片的WUE高于长春地区，但在14：00―16：00时，2个地区叶片的WUE变化并不大．在干热条件下，人参和西洋参叶片光合日下降较大，西洋参较人参具有较强光合能力．[著者文摘]

Inglés. The diurnal changes of photosynthesis in Panax ginseng and P. quinquefolium under different environmental conditions were studied in this paper. As for leaves grown under low light intensity （ 10% light transmission rate, LTR shade）, diurnal changes of net photosynthetic rate （Pn） were showed in single peak, the maximum value of P. was at 12 ： 00 am--1 ： 00 pro. As the increase of light intensity （grown under 20% , 30% and 40% LTR shade ） , Pn was increased, higher P, was measured from 9：00--11：00 am to 12：00 am--1：00 pm, and then Pn was declined at 2：00---4：00 pm. However, as for leaves grown under high light （50% LTR shade） , maximum P, were measured at 9：00--11：00 am, then, Pn was decreased from 12：00 am--1：00 pm. Specific leaf mass （dry mass per unit leaf area） and starch content was increased as the increase of light intensity and Pn. Daily depression percentage of Pn was paralleled with daily increase percentage of specific leaf mass and starch content. Maximum apparent quantum yield （AQY） was measured at 9：00--11：00 am, and had slight decline at 12：00 am--1：00 pm, the lowest value was measured at 2：00---4：00 pm. The leaves of P. ginseng and P. quinquefolium grown in Changchun region （relative higher temperature and lower relative humidity） showed higher water vapor pressure deficit（VPD） and greater daily depression percentage of Pn, AQY and Gs than those of grown in Huinan region （relative lower temperature and higher relative humidity）. For the leaves grown under Huinan region, Tr did not show decline changes at 2：00----4：00 pm; but it showed greater daily depression for those of Changchun region. The leaves grown under Huinan region had higher WUE than these grown in Changchun region at 9：00--11：00 am, and it was nearly same at 2：00---4：00 pm in two regions. The results indicated that P. quinquefolium had stronger ability in acclimatization to high tem- perature and acridness than P. ginseng.