Quantification of stress adaptation by laser-induced fluorescence spectroscopy of plants exposed to engine exhaust emission and drought

Abstract

The effects of drought and petrol engine exhaust pollutants, such as SO2 and NO2 and suspended particulate matter (SPM), on the photosynthetic activity of colocasia [Colocasia esculenta (L.) Schott], kacholam (Kaempferia galanga L.) and tapioca (Manihot esculenta Crantz) plants were studied from in vivo laser-induced chlorophyll fluorescence (LICF) spectra. An open-top chamber (OTC) of 2.5 m diameter and 3 m height incorporating an air-filtering unit was developed for this study. Plants grown inside the OTC were exposed to exhaust emissions from a two-stroke Birla Yamaha genset for 10 d, while a control group was maintained outside. Gaseous pollutants and SPM present inside the OTC during the exposure period were measured with a high-volume air sampler. The steady-state LICF spectra of the control and treated plants were recorded in the 650–750-nm region. Fluorescence induction kinetics (Kautsky effect) was also recorded during the stress period from dark-adapted intact plant leaves at the chlorophyll bands of 685 and 730 nm. The vitality indexes (Rfd-685 and Rfd-730) and stress adaptation index (Ap) derived from the induction kinetics were utilised along with the chlorophyll fluorescence intensity ratio (F685 / F730) for evaluation of stress-induced changes in plants. It has been observed that F685 / F730 ratio increased for all plants inside the OTC whereas the Rfd-685, Rfd-730 and Ap values showed a downward trend with increasing pollution stress. As compared to colocasia and tapioca, kacholam plants showed higher resistance to exhaust emission and water stress as well as better capacity to regain its photosynthetic functioning on removal of the stress. Results of this study demonstrate the capability of stress adaptation index for early quantification of the functional impairment of photosynthetic apparatus in different species of plants due to air pollution and drought stresses.

Photosynthetic response of different pea cultivars to low and high temperature treatments

“…Yet the results presented here demonstrate the good applicability of the stress adaptation index Ap in stress and eco-physiological research, since plants with higher Ap values, such as sun or HI leaves, can endure a higher stress load. The stress adaptation index Ap has also successfully been applied to quantify stress adaptation and damage of plants to petrol engine exhaust pollutants and drought (Subhash et al 2004), and permitted to differentiate more stress sensitive plants from more stress tolerant ones.…”

Detection of mosaic virus disease in cassava plants by sunlight-induced fluorescence imaging: a pilot study for proximal sensing

“…The decrease in P n with stress could be attributed to the closure of the stomata that reduces the amount of carbon dioxide necessary for photosynthesis (Subhash et al 2004;Ibaraki, Matsumura, and Gupta 2010). The reduction in the total leaf chl and P n with stress also agrees with previous study and we believe that the reduction of the total leaf chl in virus-infected leaves could be due to degradation of chloroplasts in CMD-infected leaves (Esau 1956), and consequently, less efficient photosynthetic activity is noticed during this period (Tu, Ford, and Krass 1968;Ayanru and sharma 1982;Palta 1990;Carter et al 1992;Fang, Bouwkamp, and Solomos 1998;Raji et al 2013).…”

“…Previous studies suggest a strong inverse relationship between red to far-red fluorescence ratios (F 690 :F 740 ) and chl content in plants under stress Subhash and Mohanan 1994;Agati et al 1995;Gitelson, Buschmann, and Lichtenthaler 1999;Subhash et al 2004). The ratio of the red to far-red (F 690 :F 730 ) fluorescence intensities is particularly sensitive to environmental changes and permits early detection of damage to the photosynthetic apparatus or stress conditions in plants.…”

Transcriptome-based identification and validation of reference genes for corm growth stages, different tissues, and drought stress in Taro (Colocasia esculenta)

“…The leaf, corm, petiole, and root samples were collected at the stage of three months. For drought stress, the samples of three months old were exposed to a seven-days water deficit treatment according to the previous study [ 24 ]. After harvesting, the samples were thoroughly washed with running water and then with distilled water.…”