THE RESULTS OF THE COMPREHENSIVE STUDY OF SIBERIAN SPRUCE SEEDLINGS - - PowerPoint PPT Presentation

THE RESULTS OF THE COMPREHENSIVE STUDY OF SIBERIAN SPRUCE SEEDLINGS RESPONSE TO UV-B RADIATION EXPOSURE

1Institute of Monitoring of Climatic and Ecological Systems, Tomsk, Russia 2Tomsk State University, Tomsk, Russia 3Tomsk Polytechnic University, Tomsk, Russia

Е.М. Korotkova1, V.V. Zuev1,2,3, N.E. Zueva1, O.G. Bender1, A.V. Pavlinsky1, V.L. Pravdin1

11-16 July 2016 , Tomsk ENVIROMIS-2016

• UV-B radiation is a reason of plant stress, photosynthesis degradation and

growth inhibition;

• Forest drying is a complex process, including climatic, biotic and

anthropogenic factors;

• Quantity of UV-B radiation depends on ozonosphere conditions;
• There is lower ozone content above the mountain territories;
• Thus, drying of conifer forests of South Siberia mountains can be associated

with UV-B radiation.

UV-B radiation as a factor of mountain forests drying

Ozone depletion above the South Siberia mountains Forest drying in the mountains of South Siberia is observed at:

• Kuznetskiy Alatau;
• West Sayan;
• East Sayan;
• Khamar-Daban.

The main goal: Estimation of the role of the UV-B radiation in forest drying of South Siberia mountains

Kuznetskiy Alatau West Sayan East Sayan Khamar-Daban

Experiment as a decision We are interested in:

• Vital status of the plants
• Photosynthesis and transpiration changes
• Soil moisture changes (evaporation, consumption by plants)

The aim of the present study:

To investigate the effect of additional UV-B radiation exposure on the state of conifers using not only biological, but ecological approach

About experiment

The experiment was carried out on spruce seedlings during the period from June to August of 2015. The test plants were divided into two groups: one experimental and one control group. The seedlings were planted in plastic containers and placed in the experimental room with access for the background solar radiation and natural ventilation. The experimental group of plants was exposed to UV-B radiation at a wavelength of 308 nm for 4 hours daily. The plants received daily a dose

• f additional ultraviolet radiation comparable to a 30% deficit of ozone in

the atmosphere for Tomsk. Both groups of plants were further exposed to photosynthetically active radiation from fluorescent phytolamps.

Measurments:

• Photosynthesis of the 1- and 2-

year old needle;

• Transpiration of the 1- and 2-year
• ld needle;
• Needle water content;
• Chlorophyll fluorescence

response;

• Soil moisture.

Air temperature, humidity and

• ther weather conditions were also

fixed.

Experiment design

PAR Lamps UVB-308 Lamp Emitter/fluor. signal receiver Soil hygrometer Timer Gas analyzer

Experiment

Photosynthesis, transpiration, needle water content

10 20 30 40 50 60 70 80 90 100 0,1 0,2 0,3 0,4 0,5 0,6 10 20 30 40 50 60 70 80 90 100 0,2 0,4 0,6 0,8 1,0 1,2 1,4 10 20 30 40 50 60 70 80 90 100 52 56 60 64 68 72 76

H2O excretion, mkmol m

• 2s
• 1

CO2 absorbtion, mkmol m

• 2 s
• 1

1-year old, cont 1-year old, exp 2-year old, cont 2-year old, exp

Needles:

Needle water content, %

Day

Photosynthesis rate :

1- and 2-year-old needles in the experimental group - 28% and 40% lower than that in the control group.

Transpiration rate:

1- and 2-year-old needles in the experimental group - 16% and 33% lower than that in the control group.

Needle water content:

No significant changes.

Soil moisture drying and air parameters dynamics

10 20 30 40 50 60 70 80 90 100 35 40 45 50 55 60 65 70 10 20 30 40 50 60 70 80 90 100 21 22 23 24 25 26 27 28 29 30 1,5 2,0 2,5 3,0

Air humidity Soil drying velocity, %/day Air humidity, % Air temperature, °C

Day

Air temperature

control experiment

10 20 30 40 50 60 70 80 90 100 1,3 1,4 1,5 1,6 1,7 1,8 1,9 2,0 2,1 2,2 2,3 2,4 2,5

Soil drying velocity, %/day Day control experiment soil

The chlorophyll fluorescence response in the experimental plant group showed the behavior opposite to normal response of the control plant group, revealing photosynthesis degradation and plant stress.

The results of the fluorescence response study

10 20 30 40 50 60 70 80 0,86 0,88 0,90 0,92 0,94 0,96 0,98 1,00 1,02 1,04 1,06

Day

685/740 nm, rel. units.

Control Experiment

Territory Negative deviations of ozone from normal, % 1979-1991 гг. 1992-2012 гг. Kuzneckiy Alatau 20 74 West Sayan 16 76 East Sayan 13 75 Khamar-Daban 13 76

Ozone normals 1979-1991 and 1992-2012 differences (active vegetation period V-VIII)

Ozonosphere behavior analysis

1976 1980 1984 1988 1992 1996 2000 2004 2008 2012 320 330 340 350 360

331 Ozone, D. u. Years Ozone ( V-VIII) Average 344

Pinatubo Kuznetskiy Alatau West Sayan East Sayan Khamar-Daban

The increase

• f

intensity

• f

conifer forests drying process in South Siberia mountains is registered since the second half

• f 1990-s.

Summary

• The experiment showed the negative impact of UV-B radiation on

photosynthesis and its decrease in the needles of different ages. Chlorophyll fluorescence response also reveals the changes in the photosynthetic apparatus in the experimental plant group. The additional UV-B radiation exposure led to an increase in water consumption from the soil, reducing the level of soil moisture available to plants. Thus, the set of adverse effects due to an extra dose of UV - B radiation exposure, can be manifested not only directly, resulting in the weakening by inhibiting photosynthesis and growth, but also indirectly, i.e. creating a moisture deficit in the soil, due to increased water consumption.

• Actually, the increase of intensity of conifer forests drying process in South

Siberia mountains since the second half of 1990-s is observed against a backdrop of ozone depletion from 1992.

THANK YOU FOR ATTENTION!

Е.М. Korotkova1, V.V. Zuev1,2,3, N.E. Zueva1, O.G. Bender1, A.V. Pavlinsky1, V.L. Pravdin1

11-16 July 2016 , Tomsk ENVIROMIS-2016