摘要
以铁皮石斛为供试材料,通过无土栽培方式,采用聚乙二醇(PEG-6000)模拟干旱试验,设置0%PEG-6000(对照)、6%PEG-6000、12%PEG-6000、18%PEG-6000和24%PEG-6000共5个水平,研究干旱胁迫强度和胁迫时间对铁皮石斛叶片活性氧含量积累、保护酶活性、SPAD值和叶绿素荧光特性的影响。随着干旱胁迫时间的延长和胁迫强度的增加,铁皮石斛叶片H_2O_2含量和O_2-·含量呈现逐渐上升的趋势,但O_2-·含量在干旱胁迫第8d开始上升幅度减小。PEG-6000浓度6%、12%、18%和24%的4个处理的叶片POD活性和SOD活性随胁迫时间的延长呈现先增加后降低的趋势,且在胁迫第8天时达到最大值,较同一时间的对照分别增加108.33%、154.17%、212.50%、245.83%和46.79%、54.53%、58.73%、86.78%。干旱胁迫下铁皮石斛叶片SPAD值均低于对照,并随胁迫强度的增加表现出逐渐降低的趋势,但处理间SPAD值下降的程度表现出减缓的趋势,SPAD值与干旱胁迫程度的相关系数为-0.982 11,具有极显著负相关关系。随着干旱胁迫时间的延长和胁迫强度的增加,铁皮石斛叶片的最大荧光(Fm)、最大光化学效率(Fv/Fm)和光化学卒灭系数(qp)逐渐降低,而初始荧光(Fo)却不断升高,光反应能力降低。
To research the effects of drought density and time on active oxygen scavenging systems （ active Oxygen accumulation, protective enzyme activity, SPAD value） and chlorophyll fluorescence characteristics of Dendrobium officinale leaves, 5 different levels of experiments, 0% PEG-6000 （control）, 6% PEG-6000, 12% PEG-6000, 18% PEG-6000 and 24% PEG-6000, were set by using polyethylene glycol （PEG-6000） as simulated drought condition in soilless culture. With the increase of drought stress time prolonged and the stress intensity, iron content of H202 and O2-· content of Dendrobium officinale leaf increased, but the content of O2-· stress increased slightly from the eighth day. The POD activity and the SOD activity increased at the beginning then decreased under 4 PEG-6000 concentration treatments （6%, 12%, 18% and 24% ）, and reached their maximum in the eighth day （ increased by 108.33%, 154. 17%, 212. 50%, 245.83% and 46. 79%, 54. 53%, 58.73%, 86. 78% respectively compared with the control）. The SPAD values under drought condition was lower than the control, and showed an tendency of decreasing with the stress intensity increasing, but the decreasing tendency showed slowing down among different treatments, the correlation coefficient between SPAD value and drought stress was-0. 982 11,showed extremely significant negative correlation. With the increase of drought stress time and the stress intensity,the maximum fluorescence （Fm）, the maximal photochemical efficiency （Fv/Fm） and photochemical inactivation stroke coefficient （QP） decreased gradually, while the initial fluorescence （Fo） increased.
出处
《西部林业科学》
CAS
2017年第6期103-107,共5页
Journal of West China Forestry Science
关键词
干旱胁迫
铁皮石斛
活性氧代谢
SPAD值
叶绿素荧光
drought stress
Dendrobium officinale
active oxygen metabolism
SPAD value
chlorophyll fluorescence
