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)

Knight & Ackerly (2002) v Thermotolerance : Leaf temperature tolerance can be quantified as the temperature response of Photosystem II (PSII) function - dark-adapted Chlorophyll a fluorescence. v T50 is the temperature at which PSII function is reduced to 50% of control levels as an index of leaf temperature tolerance. Sastry & Barua (2017) 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)

Introduction

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

• 2. Leaf discs were punched with a cork borer (0.8 cm radius)
• 1. Plant Sample Collection
• 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

Methodology

Herbaceous Native Species Shruby Native Species

Herbaceous Invasive Species Herbaceous Native Species

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

42 43 44 45 46 47 48 49 50 51 52 53

T50 for PSII function (°C)

Thermotolerance of 9 Species

• Q3. Is thermotolerance compared using two

different instruments comparable?

• 3 species: Ixora bracheata, Duranta sps., Ziziphus

sps.

• Two machines: Panwin Fluorimeter, Fluorpen FP100

Duranta sp.

RED: Panwin BLUE: Fluorpen FP100

Ixora bracheata

RED: Panwin BLUE: Fluorpen FP100

Ziziphus sp.

RED: Panwin BLUE: Fluorpen FP100

INFERENCES/CONCLUSIONS????

• Fluorpen gave a higher T50 than the T50 given by Panwin for

2/3 species.

• Fluorpen gave a higher variation in T50 than the variation in T50

given by Panwin for all 3 species.

• Handling errors?: Ziziphus species may have too high T50:

>52oC. Sastry & Barua (2017) got a max T50 of ~ 50.5oC.