Effects of UV-B on the growth of Vigna radiata ( 綠豆 ), Vigna angularis ( 紅豆 ) and Glycine max ( 大豆 ) ST. PAUL’S CO-EDUCATIONAL COLLEGE CHUI HO YIN PAUL CHAN YUN YIN CYRUS LEE WAI LAM BRYAN

Hey! Dear, I have a fabulous yield this year!!! Dad! We may get a poor yield next ten years!!! WHY!?!?!

光 禿 禿 ?

Observations and facts Ozone concentration decreases –Higher amount of ultraviolet-B (UVB) radiation reaching the earth –cause harmful effects to the biosphere

Literature Review The effect of UVB on plants Negative impacts of UVB on Glycine max: –Decrease the areas and the number of leaves –Decrease height of the stems –Decrease the photosynthetic rates and the evaporation rate –Delay the growth process

Problem?? Will the yield of the crops be reduced???

Objectives 1.To find out the effect of UVB radiation on 3 types of plants (Vigna radiata 綠豆, Vigna angularis 紅豆 and Glycine max 大 豆 ) 2.To find out which of these three plants has stronger resistance to the damaging effect of UVB radiation

Hypothesis Under extra UVB: The growth processes would be delayed Fewer leaves would be developed Shorter stems would be developed

Set-up 1B Vigna angularis Set-up 1C Glycine max Set-up 1A Vigna radiata Set-up 2B Vigna angularis Set-up 2C Glycine max Set-up 2A Vigna radiata Methodology

Set-upType of seedVolume of water added daily (cm³) Number of seeds Set-up 1 (control set- up) 1 A Vigna radiata 綠豆 B Vigna angularis 紅豆 C Glycine max 大豆 8440 Set-up 22 A Vigna radiata 綠豆 B Vigna angularis 紅豆 C Glycine max 大豆 8440

Variable Table Controlled variablesIndependent variablesDependent variables Number of seeds used Number of cotton layers used Volume of water poured everyday Types of plants Illumination treatment Number of leaves Length of stems Colour of leaves

Illumination treatment Setup 1 7:0018:00 Sunlight Setup 2 7:0018:0013:0016:00 Sunlight Sunlight + UV (300nm-400nm) Sunlight

Result Setup 1BSetup 1CSetup 1A

Setup 2BSetup 2CSetup 2A

Colour of leaves Without extra UVB (Set-up 1): –green With extra UVB (Set-up 2): –green → yellow → brown →black (died)

CONCLUSION 1 Under extra UVB: –Delayed germination –Delayed foliation –Fewer leaves developed –Shorter stems developed –Colour of the leaves changed from green to black

WHY??

Analysis Set-up 2 –Green → Yellow → Brown →Black Maybe UVB blocks some nutrients from being absorbed by plants –Slow down chlorophyll formation –Cause the deficiency and poor growth

Further investigation Measure the amounts of photodimer and photolyase before and after UVB illumination Investigate the relationship between the UVB dosage and the amounts of photodimer formed Investigate the effect of UVB on the photosynthetic rate of plants

Which plant has the best resistance to UVB???

Both Glycine max ( 大豆 ) & Vigna angularis( 紅豆 ) had shown small difference

1 5 4

Vigna radiata 綠豆 had the smallest difference

1 5 3

Vigna radiata 綠豆 had the smallest difference

Vigna radiata ( 綠豆 ) in the set-up with UVB died latest among three set-ups.

CONCLUSION 2 The growth of Vigna radiata( 綠豆 ) is least affected under extra UVB condition among the three plants Vigna radiata ( 綠豆 ) has the best resistance to UVB among the three plants (Vigna radiata, Vigna angularis and Glycine max) studied

Further investigation Investigate the effect of UVB dosage on the growth of Vigna radiata ( 綠豆 ) Investigate whether Vigna radiata ( 綠 豆 ) from different climatic regions show different resistance to UVB

In order to have a good harvest, is it more beneficial for me to grow Vigna radiata? I think…

THANK YOU!!! Please protect our earth!!!!

REFERENCE 1. 二氧化碳, 臭氧, 紫外輻射與農作物生產 ─ 氣象出版社 2. Elevated Ultraviolet (UV)-B Radiation and Agriculture. Springer Press. 3. Plants and UV-B ─ Responses to Environmental Change. Cambridge University Press. 4. Ozone crisis: the 15-year evolution of a sudden global emergency. John Wiley and Sons Press. Websites htmlhttp:// html

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Comparison of the highest average number of leaves between the set-ups with (2A, 2B, 2C) and without UVB (1A, 1B, 1C) Plant usedSet-upsThe highest average number of leaves recorded Difference between two set-ups Vigna radiata1A (without UVB) A (with UVB)0.7 Vigna angularis 1B (without UVB) B (with UVB)0.8 Glycine max1C (without UVB) C (with UVB)0.7

Difference of the day of first foliation between the set-up with (2A, 2B, 2C) and without UVB (1A, 1B, 1C) Plant usedSet-upsDay of the first foliation recorded Difference between two set-ups Vigna radiata- UVB UVB11 Vigna angularis - UVB45 + UVB9 Glycine max- UVB64 + UVB10

Difference of day of germination between the set-ups with (2A, 2B, 2C) and without UVB (1A, 1B, 1C) Plant usedSet-upsDay of germination Difference between two set-ups Vigna radiata1A (without UVB) A (with UVB)11 Vigna angularis 1B (without UVB) 45 2B (with UVB)9 Glycine max1C (without UVB) 63 2C (with UVB)9

Comparison of the highest average height recorded between the set- ups with (2A, 2B, 2C) and without UVB (1A, 1B, 1C) Plant usedSet-upsHighest average height recorded Difference between the two set-ups Vigna radiata1A (without UVB) A (with UVB)9.7 Vigna angularis1B (without UVB) B (with UVB)16 Glycine max1C (without UVB) C (with UVB)13.4

The day of in which the plants grown under UVB died Plant usedSet-upsDay of death Vigna radiata2A (with UVB) 23 Vigna angularis2B (with UVB)22 Glycine max2C (with UVB)19

“Heating effect” of UVB is negligible…….. Initial temperature inside the acrylic box with switched-on UV lamp ( ℃ ) Temperature inside the acrylic box with switched on UV lamp after 3 hours ( ℃ )

The acrylic box