Diurnal changes in photosynthesis and antioxidants of Angelica sinensis as influenced by cropping systems

Abstract

Diurnal dynamics of photosynthetic character of Angelica sinensis, as well as effect of continuous cropping on leaf photosynthetic character, antioxidant enzyme activity and growth of A. sinensis were investigated under field condition. The results showed that the diurnal net photosynthetic rate of A. sinensis in sunny day exhibited a double-peak pattern, and the peaks occurred at 9:45 and 16:45 h, respectively. There was a significant midday depression with A. sinensis, which was caused principally by stomatal factors such as stomatal conductance. The results also showed that net photosynthetic rate (P N ), transpiration rate (E), stomatal conductance (g s ), intercellular CO 2 concentration (C i ), and chlorophyll content (Chl) of A. sinensis plants under continuous cropping were significantly lower than those of the control. The activity of total superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), and growth parameters of A. sinensis plants were significantly decreased under continuous cropping condition. This study provides evidence of continuous cropping obstacle effect on photosynthesis, antioxidant enzyme activity, and growth parameters of A. sinensis in a field experiment, which partly explained the yield reduction of A. sinensis in the field, when it was cultivated continuously on the same soil.

Daily dynamics of photosynthetic parameters in beech population under periodical drought conditions

“…These two peaks of photosynthesis are recognized as typical diurnal photosynthetic dynamics of some woody plants measured during the daily climatic variation [18], and also during severe drought [19,20]. Similar rhythmical changes in the net photosynthetic rate were also observed for herbaceous plants: an early morning maximum, then a pronounced midday depression and a subsequently small recovery late in the afternoon [21,22]. The midday depression could be explained by significant and negative correlation between photosynthesis and weather conditions like high temperature, as well as a shortage of precipitation.…”

Effect of Intercropping of Angelica sinensis with Garlic on its Growth and Rhizosphere Microflora

“…Plants generate more reactive oxygen species (ROS) and stimulate resistance responses of plants when exposed to the stressful conditions (Thoma et al, 2003). These ROS are either toxic by-products of aerobic metabolism or regulators of growth, development and the defense pathways (Ding et al, 2007;Zhang et al, 2013). Toxic ROS can affect membrane permeability, induce lipid peroxidation, and ultimately lead to programmed cell death.…”

Effects of Soil Sterilization on Growth of Angelica sinensis Plant and Soil Microbial Populations in a Continuous Mono-cropping Soil

“…Superoxide dismutase (SOD) activity was measured by its ability to inhibit the photochemical reaction of NBT at 560 nm (Zhang et al, 2013). One unit of SOD activity was defined as the enzyme amount causing 50% inhibition of NBT reduction.…”

“…Peroxidase (POD) activity was measured by monitoring the increase in absorbance at 470 nm due to guaiacol oxidation at 25°C (Zhang et al, 2013). One unit of POD activity was defined as the increase in absorbance at 470 nm for 1 min due to guaiacol oxidation.…”

“…Previous studies on the causative factors for replanting yield and quality decline mainly focused on autotoxicity (Zhang et al, 2010) and physiological activity (Zhang et al, 2013) in A. sinensis. Moreover, the effect of continuous cropping on soil microbial populations in rhizosphere also has been investigated (Zhang et al, 2015b).…”