Stomatal clustering in Begonia associates with the kinetics of leaf gaseous exchange and influences water use efficiency

Stomatal clustering in Begonia associates with the kinetics of leaf gaseous exchange and influences water use efficiency

1. Stomatal clustering in Begonia associates with the kinetics of leaf gaseous exchange and influences water use efficiency Maria Papanatsiou , Anna Amtmann and Michael R. Blatt February 2017 Impact factor: 5.52 Presented by Azqa azhar 12-arid-193 M sc (H ons ) 3 rd

2. INTRODUCTION 2

3. Introduction… 3 (Neale et al , 2006)

4. 4 Allow gaseous exchange Adjust opening and closing of stoma (Hetherington and Woodward, 2003). Stomata control trade-off between transpirational water loss and carbon gain and therefore they play a crucial role in water use efficiency (WUE) One cell spacing rule

5. 5 Contiguous Non-Contiguous (Payne, 1970; Metcalfe and Chalk, 1979; Chen, 1996; Tang et al., 2002 )

6. 6 YODA, MKK4/5, MAK3/6, ICE/SCRM2 mutation in these genes causes stomatal clustering ( Zhou L et al , 2010 )

7. 7 Stomatal clustering in begonia Meristemoid mother cell Stomatal lineage ground cell Guard mother cell Guard cell (Lau O. S et al , 2012)

8. Objective 8

9. MATERIAL AND METHODS 9

10. Planting Material and Growth Condition 10

11. Gas Exchange 11

12. 12 External light source (LI-COR 6400-18) LI-COR 6400 XT Infrared Gas Analyzer

13. Stomatal Assay 13

14. 14 (5 mM MES- NaOH pH 6.15, 60 mM KCl)

15. 15

16. Stomatal Aperture Wa is the aperture width and La is the aperture length Stomatal Size Ws is the stoma width and Ls is the stoma length Stomatal conductance 16 d is the diffusivity of water vapour in air (m2 s–1) v is the molar volume of air at 1 atm and 22 °C (m 3 mol –1 ) SD is stomatal density (m –2 ) l is the pore depth (m)

17. Statistical Data and Analysis 17

18. RESULT AND DISCUSSION 18

19. 19 Stomatal characteristics of two Begonia species representative micrographs from the abaxial side of B. coccinea and B. plebeja . Scale bar=20 μm Non-contagious Clusters 24% smaller stomata Extra non stomatal cluster 70 μmol m–2 s–1 light in long-day conditions (16/8 h of light/dark), 22 °C/18 °C (light/dark) temperature, and 60%/70% (light/dark) relative humidity Stomatal density (light grey) and stomatal size (dark grey)

20. 20 Maximum stomatal opening, and percentage of stomatal closure Relative to the maximum for that species B. plebeja opened 22% less when compared with B. coccinea in opening buffer treatment for 2 hour under high light intensity Closing buffer and darkness for 90 min

21. 21 34% greater anatomical conductance to water vapor GWmax in B. Plebeja

22. 22 Stomatal patterning for gas exchange responses. (A) Representation of the experimental design measuring stomatal conductance ( gs ) response from dark-adapted leaves exposed to light and on subsequent transfer back to darkness. (B and D) and steadystate rates (C and E) of gs upon exposure to a light intensity of 70 μmol m–2 s–1 (dark grey) and 400 μmol m–2 s–1 (light grey) and on transfer back to darkness. 42% faster closure response in B. Plebeja when transferred from high light intensity to dark

23. 23 Effect of photosynthetic active radiation on CO2 assimilation. Light curves from B. coccinea (open triangles) and B. plebeja (filled triangles) display the assimilation of CO2 over a series of quantum flux densities ranging from 0 to 800 μmol m–2 s 1 . B. Plebeja showed smaller CO2 assimilation rates in comparison with those of B. coccinea at saturating light intensities

24. 24 Intrinsic water use efficiency ( WUEi ) of Begonia plants under three light regimes. The WUEi of B. coccinea (white bars) and B. plebeja (black bars) was estimated as the ratio of the maximum CO2 assimilation rate over stomatal conductance at a light intensity of 70, 200, and 400 μmol m–2 s–1. WUEi of ~30% compared with B. coccinea plants at light intensities of 70 μmol m–2 s–1 and 200 μmol m–2 s–1

25. CONCLUSION 25

26. Future prospects 26

27. Thank you 27