Effect of light intensity on photosynthesis and accumulation of sennosides in plant parts of senna ( Cassia angustifolia
- PDF / 622,484 Bytes
- 5 Pages / 595.276 x 790.866 pts Page_size
- 24 Downloads / 163 Views
ORT COMMUNICATION
Effect of light intensity on photosynthesis and accumulation of sennosides in plant parts of senna (Cassia angustifolia Vahl.) Saravanan Raju • Sonal Shah • Narendra Gajbhiye
Received: 5 December 2012 / Accepted: 29 June 2013 / Published online: 20 September 2013 Ó Indian Society for Plant Physiology 2013
Abstract The production of secondary metabolites in medicinal plants is influenced by quality of light. Two senna cultivars (ALFT 2 and Sona) were studied under field conditions at four different light levels (25, 50, 70 and 100 % of full sunlight) for photosynthetic performance and sennoside accumulation. The cultivar ALFT 2 recorded highest Pn values of 31.27 lmol CO2 m-2 s-1 at 100 days after sowing (DAS), whereas Sona recorded the highest value of 30.7 lmol CO2 m-2 s-1 at 60 DAS under 100 % light. Lowest Pn values of 12.1 and 11.07 lmol CO2 m-2 s-1 were recorded in ALFT 2 (120 DAS) and Sona (150 DAS), respectively under 25 % light. Sennoside A reduced by 30 % under 25 % light in leaf tissue of ALFT 2, whereas, a reduction of only 16 % was observed in Sona. Highest sennoside B content was observed in ALFT 2 under full sun light (2.03 %). ALFT 2 recorded comparatively higher total sennosides (4.76 %) in pods than Sona (4.57 %) under full light. The gradual decline in Pn with later growth stages could be the reason for steady decline in sennosides content, particularly in the leaves and pods of both the cultivars. Keywords Net photosynthesis Shade Secondary metabolites Sennoside content
S. Raju (&) Central Tuber Crops Research Institute, Sreekariyam, Thiruvananthapuram 695017, Kerala, India e-mail: [email protected] S. Shah N. Gajbhiye Directorate of Medicinal and Aromatic Plants Research, Boriavi, Anand 387310, Gujarat, India
Senna is one of the most commonly used laxative drugs worldwide and its purgative action is known from time immemorial. The Tinnevelly senna (Cassia angustifolia Vahl.) belongs to plant family Fabaceae. Two anthraquinone glycosides namely; sennoside A and sennoside B are the principal phytoconstituents responsible for its characteristic purgative action. Anthraquinone glycosides are involved in plant defense against herbivores and have evolutionary significance for the adaptability of the species in which these compounds are present. Sennoside A and B together are responsible for up to 40–60 % activity of crude senna. Sennosides are not restricted to leaflets only; they are present in various vegetative and reproductive parts (underground as well as aerial). Maximum content of sennoside B is found in aerial parts. Hence, leaves and fruits of the senna plant were used to an equal extent. Though synthetic alternatives for sennosides are available in the market, sennoside formulations are widely used as safe laxatives (Atzorn et al. 1981). Senna is cultivated in many parts of India in warm and dry regions, in nutrient-poor, sandy soils as rainfed crop (Pareek et al. 1983). Light is one of the major environmental factors, which affect plant growth and yield (Boardma
Data Loading...
