A Comparative Study of Thermotolerance with few Native and Exotic - PowerPoint PPT Presentation

A Comparative Study of Thermotolerance with few Native and Exotic Species of Sirsi, Karnataka Supriya K Salimath Dr. Ankur Arun Patwardhan Subham Banerjee Manaswi Raghurama Abdulla Naseef Plant Ecology and Ecophysiology Workshop (17-22 September, 2018)

Introduction v Thermotolerance : Leaf temperature tolerance can be quantified as the temperature response of Photosystem II (PSII) function - dark-adapted Chlorophyll a fluorescence. Knight & Ackerly (2002) v Dark adapted fluorescence is the ratio of variable and maximum fluorescence, Fv/Fm , where Fv = (Fm − Fo ), and Fm and Fo are the maximum and basal fluorescence yield, respectively. Havaux et al. (1992), Barua et al. (2003) v T 50 is the temperature at which PSII function is reduced to 50% of control levels as an index of leaf temperature tolerance. Sastry & Barua (2017)

Questions: 1. Is there any difference between the heat tolerance capability of Invasive and Native Plant Species? 2. Do different life forms exhibit distinguishable thermotolerance power?

Plant Species

Methodology 1. Plant Sample Collection 2. Leaf discs were punched with a cork borer (0.8 cm radius) 3. Leaf discs were packed properly for heat treatment 4. immersed in a temperature controlled refrigerated water bath 5. leaf discs were allowed to dark adapt at room temperature 6. chlorophyll a fluorescence ( Fv/Fm ) was measured with a PAM 2500 fluorometer

Shruby Native Species Herbaceous Native Species

Herbaceous Native Species Herbaceous Invasive Species

Thermotolerance of 9 Species 53 52 51 50 T 50 for PSII function (°C) 49 48 47 46 45 44 43 42 IXOR DURA ZIZI CHOD CATO AGER BLUM SIAC CLED T50 for PSII function (°C) 48.25 49.94 52.45 46.24 45.70 46.56 48.15 49.08 45.99

Q3. Is thermotolerance compared using two different instruments comparable? • 3 species: Ixora bracheata , Duranta sps., Ziziphus sps. • Two machines: Panwin Fluorimeter, Fluorpen FP100

RED : Panwin BLUE : Fluorpen FP100 Duranta sp.

RED : Panwin BLUE : Fluorpen FP100 Ixora bracheata

RED : Panwin BLUE : Fluorpen FP100 Ziziphus sp.

INFERENCES/CONCLUSIONS???? • Fluorpen gave a higher T 50 than the T 50 given by Panwin for 2/3 species. • Fluorpen gave a higher variation in T 50 than the variation in T 50 given by Panwin for all 3 species. • Handling errors?: Ziziphus species may have too high T 50 : >52 o C. Sastry & Barua (2017) got a max T 50 of ~ 50.5 o C.