Effects of Light on Tissue Cultures

Cell & Tissue Culture

BSc (Hons) Biotechnology

University of Mauritius

Presented By:

- Ritesh Bhagea

- Rouksaar Buctowar

- Huda Nazeer

- Christabelle Cecile

- Keshavi Ghoorbin

Date: 20th March 2014

Overview

● Aims and Objectives

● Introduction

● Materials and Methods

● Result

● Discussion

● Problem with varying light intensity - How varying light

intensity affects tissue cultures

● Alternatives / Improvements

● Conclusion

● References

● Luxmeter: Device to measure light intensity (SI unit: lux,

Symbol: lx) per unit area.

Introduction

● Importance of light in tissue culture:

o Type of light source will affect light

intensity.

o Light intensity affects photosynthesis

ability: leaf anatomy, chlorophyll

formation & chloroplast differentiation

(Aitken-Christie J., et al, 1994).

o Callus formation & growth: low light

works better for carrot callus.

MaterialsLuxmeter

Fluorescent Tubes Incubator

Laminar Flow

Hood (covered it

with dark cloth)Tray Aluminium Foil

Newspaper

Measuring light intensity using a luxmeter:

● Experiment carried out in the Biotechnology lab and outside on FoA

ground.

● Light meter placed in the middle of the work area.

● Light sensor gripped steadily and flat - pointing towards light source.

● Three readings taken for the same place.

● Lux values converted into Watt - mean and standard deviation

calculated.

Note: The range on the luxmeter was changed depending on the

environment - outside and inside - to get more exact values of lux.

Methods

Results

Conditions Light Intensity Means

(Watt)

A Using one fluorescent tube 0.014 ± 2.84 x 10^-3

B Using two fluorescent tubes 0.043 ± 4.12 x 10^-3

C Using three fluorescent tubes 0.056 ± 7.36 x 10^-3

D Using four fluorescent tubes 0.069 ± 5.24 x 10^-3

E In the incubator 0.000

F In dark laminar airflow 0.000

G In a tray covered with aluminium

foil0.000028 ± 0.019 x 10^-3

H In a tray covered with newspaper 0.00012 ± 0.025 x 10^-3

I Outside in sunlight 0.86389 ± 0.042

Table 1 : Intensity of light from different sources.

How light intensity affects tissue cultures:

● More light = increased adaptation of leaves in terms of leaf anatomy,

chlorophyll formation & chloroplast differentiation.

● In vitro = low light = lack of grana stacking, thinner leaves, poorly defined

mesophyll with large intercellular spaces, 1 layer of palisade cells only.

● Hence, cultures cannot use light to its maximum, photosynthesis saturates

at low light levels.

● Increasing light intensity during culture would increase photosynthesis,

given all other conditions required are present (Aitken-Christie J., et al,

1994).

● However, low light intensity, for instance the dark, is beneficial for callus

formation in carrot.

Discussion

● Explants are placed in jars

that are short and have an

opaque/ metallic cap.

● This prevents light from

reaching the explant which is

carrying out photosynthesis.

● Stressful for the explant

when the jars are crammed.

Problems

Figure 1: Jars crammed unto shelf - bad

light distribution.

● The lighting system

● Use of fluorescent tubes-cool

daylight/white

● 5 tubes per shelves

o Some were flashing

(defective ones)

● Different brands: Lamptan,

Astra, Tungsram, Osram

o Leads to different quality of

light

Problems

Figure 2: Out of 5, only 3 lamps are

working.

● Osram lamps- 36W

o Colour - Daylight

o Luminous flux at 25 °C = 3350 lm

o Color rendering index Ra = ≥ 80

o Color temperature = 2700 K

o Lifespan = 20000 hours

● Lamptan lamps

Problems

Use of LED lights

● Precise beam control.

● Accelerate plant growth.

● Do not generate heat hence do not heat the plants below.

● 3 times for efficient than fluorescent lamps ( LED: 20W,

Fluorescent:~58W).

● LED are used for about 12 hrs compared to fluorescent light 16hr per

day.

● Lifetime: approximately 8 years.

Overall, LED is best for raising the best plants for the least amount of

money. Commercial growers can cut their electric bills for plant lighting

roughly in half by using colored LED lighting instead of fluorescent

lighting because they essentially pay only for the light the plants need.

Improvements

● Plants use red and blue

light the most.

● Using LED of Red and

Blue colour,

o Plants get light of

required wavelength

o Money is saved

● Correct ratios must be

established for red:blue

Improvements

● Transparent caps

- Allowing transparency for maximum light to enter the jars so that the

explant can carry out photosynthesis

● Spacing the culture jars

- To allow light to pass sideways

● Use of same lighting brands

- To avoid variation in quality of light

Improvements

● Source of light affects light intensity.

● Increasing no. of fluorescent tubes increases light intensity.

● Light intensity outside is greatest.

● Aluminium foil is more effective at preventing light from

passing through - more opaque.

Conclusion

References

● http://www.hemp-technologies.com/page87/page87.html

● http://www.ehow.com/about_5452900_led-vs-fluorescent-lighting.html

● http://cipotato.org/genebank/conservation-methods/images/in-vitro-jpg\

● http://www.ledinside.com/news/2011/7/illumitex_20110712

● http://www.osram.com/osram_com/index.jsp

● http://www.carnivorousplants.org/howto/SoilsWater/Lighting.LED.php

● http://www.rapidtables.com/calc/light/lux-to-watt-calculator.htm

● http://upload.wikimedia.org/wikipedia/commons/0/09/Plant_Tissue_Cultu

re_Lab_-_Atlanta_Botanical_Garden.JPG

Thank you for your attention!