Effect of light irradiations on photosynthetic machinery and antioxidative enzymes duringex vitroacclimatization ofTylophora indicaplantlets

Abstract

In the present communication, we studied the effect of light stress on pigment contents, net photosynthetic rate, electrolyte leakage, malondialdehyde concentration and various antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and ascorbate peroxidase (APX) during acclimatization of micropropagated Tylophora indica plantlets. Pigment (Chlorophyll a, b and carotenoids) contents in ex vitro formed leaves were found significantly higher compared to the in vitro formed ones. In vitro plantlets (day 0) exhibited a low photosynthetic activity, but with the emergence of new leaves a significant increase in net photosynthetic rates was observed. Changes in the activity of the antioxidant enzymes system were also observed during the critical days of acclimatization. Plantlets showed increased levels of SOD production, indicating its preventive mechanism of membrane oxidation and damage to biological molecules in high light (HL) acclimatized plantlets. The CAT activity increased at both low lights (LL) and HL during the whole period of acclimatization. Likewise, photoexposure of plantlets at LL and HL showed elevated activity of GR and APX against 0 day plantlets.

Physiological and biochemical parameters influencing ex vitro establishment of the in vitro regenerants of Albizia lebbeck (L.) Benth.: an important soil reclaiming plantation tree

“…Therefore, an increase in SOD and CAT activities in the process of acclimatization suggests an up-regulation of the plant protective mechanism against oxidative stress. These results are in consistent with the earlier findings of Faisal and Anis (2010) in Tylophora indica, Varshney and Anis (2012) in Tecomella undulata and Perveen et al (2013a) in Abrus precatorius. Similarly, elevation in activities of both APX and GR suggests chloroplastbased detoxification of ROS (Perveen et al 2013a).…”

“…While, a decline in photosynthetic parameters during initial 14 days of acclimatization, may be because of the low photochemical activity of the persistent leaves or newly formed leaves (Perveen et al 2013a). These results are in accordance with the reports on Calathea louisae (Van Huylenbroek et al 2000) and Tylophora indica (Faisal and Anis 2010). Likewise, in Calathea louisae and Spathiphyllum floribundum substantial increase in P N was measured with the fully developed new leafs (Van Huylenbroeck et al 1998, 2000.…”

In vitro mass propagation of Murraya koenigii L

“…Hence, the extent of the damaging effects of ROS depends on the effectiveness of the antioxidative systems, and an increase in the SOD, CAT, GR and APX activities during acclimatization suggests an up-regulation of the plant protective mechanism against oxidative stress and chloroplast-based detoxification of ROS. The results are in accordance with the earlier findings in Tylophora indica (Faisal and Anis, 2010) and in Abrus precatorius (Perveen et al, 2013a,b).…”

Synthetic seed production and physio-biochemical studies inCassia angustifoliaVahl. — a medicinal plant

“…During the last few years, considerable efforts have been made for in vitro regeneration of this medicinally valuable species from different explants [2-4, 33-34, 36-38]. The in vitro growth conditions can result in the formation of plantlets of abnormal morphology, anatomy and physiology which resulted in high percentage of plantlets death because of sudden changes after their ex vitro transfer [11,17,28]. The physiological status of in vitro grown plantlets during acclimatization is an important factor determining success rates [39] and is a crucial step for many species, requiring time and expensive installation that restrict the commercial application of the micropropagation processes.…”