invitro propagation of ginger Hardening.pptx

invitro propagation of ginger

1. Hardening and Acclimatization Muhammad Zeshan Scientific Officer

2. Acclimatization Adaptation of plantlets to new environment Also known as “hardening off” Definition Acclimatization is the phenomenon whereby plants morphologically, physiologically and anatomically adjusts from in-vitro to ex-vitro environmental conditions OR Acclimation is the process by which plants adjust their morphology, physiology, and anatomy to the different environmental conditions found outside of a laboratory setting.

3. Changes occur during acclimatization Morphology  ( physical appearance of a plant) Plants develop thicker leaves More extensive root system to help them better survive in the new environment. Physiology  ( the way a plant functions) Plants may adjust their metabolism, water use, and nutrient uptake to better cope with the new environmental conditions. Anatomy  ( internal structure of a plant) Plants may develop new tissues or modify existing tissues to help them better adapt to the new environment.

4. Difference of growth conditions In-vitro Presence of growth regulators High relative humidity Low light intensity <3000 Optimum temperature Poor gaseous exchange Utmost physical care is taken Ex-vitro Absence of growth regulators Low relative humidity High light intensity >120,000 lux Variable temperature Gaseous exchange must be done Changes of physical tragedy like wind flow, water currents, etc.

5. Conditions that make problem for tissue cultured plants to adapt outside In artificial /controlled environment; Temperature is constant High relative air humidity High availability of nutrients Low light intensity Low CO2 concentration

6. How these factors affected the ex-vitro plantlets? High relative air Humidity Abnormal functioning of stomata directly influences the rate of transpiration in plants or in other words, it affects the rate at which a plant absorbs and utilizes water for growth. Low light intensity and low CO2 concentration Low carbon dioxide concentration, and high sugar in the media, Low rate of photosynthesis, Little or no leaf formation, Low growth of plants

7. High availability of nutrients Weaker roots as compared with field plants Difficulty in up taking nutrients from soil Show abnormalities in morphology upon transfer to green house conditions Constant Temperature Broad spectrum sunlight and higher fluctuating temperature, Charring of leaves (burning of leaves/browning of plant tissues) and wilting of plants. Direct transfer of plantlets to sunlight can also inhibit the process of photosynthesis which is necessary for energy production.

8. Aseptic Environment Another major cause of mortality in tissue cultured plantlets is their sudden exposure to microflora present in the soil. As these plants are not sufficiently resistant to such organisms, they get infected easily and do not survive.

9. How in-vitro plants are different from ex-vitro No or ill structure epicuticular wax Abnormal function of stomata Low net photosynthetic rate In the multiplication and rooting stage, the high humidity leads to no or ill structure epicuticular wax, abnormal function of stomata, and some healthy secondary roots. The high humidity in combination with stagnant inside air and nutrition in the medium, cause suppression of water and nutrient uptake by the plantlets, in the multiplication and rooting stages. It also causes growth retardation, physiological disorders, and a variation in size and developmental stage of the plantlets to a certain extent. The low light intensity, low CO2 concentration, and high sugar in the media lead to low net photosynthetic rate, little or no leaf formation, and low growth rate of plants.

10. Key factors for acclimatization of plants it is necessary to transfer the plants from a cultured environment to a greenhouse providing the same environment, in which it was cultured in the lab. To transfer the plantlets in the greenhouse, wash them gently under running tap water to remove any sticking media. Then, transfer the plantlets to a potting mix, irrigated with inorganic nutrient solution. A variety of potting mixes are available today including peat, vermiculite, soil, sand, etc.

11. THE FIRST TWO WEEKS Maintain high humidity by covering Make holes to reduce humidity Keep in shade (Protects from Solar light) The first shock that the plantlets will get is the change in media from organic nutrient to inorganic nutrient. But, this will activate the photosynthetic machinery of plants and prepare them to withstand low humidity. Today, computer-controlled rooms are also created that maintain high humidity for plants with enough light and CO2 for photosynthesis at the same time. To increase the survival at the acclimatization stage providing an environment to plantlets similar to the greenhouse environment at the multiplication and rooting stage,

12. Keep the culture vessels with loose lids for a few days in the greenhouse. leave the plantlets in shade for 3-6 days under diffused natural light. This would help them to establish under new environment. According to scientists, acclimatization should occur in 2-3 phases where you gradually expose plantlets first to greenhouse and then to field conditions. In order to adapt plants from high to low humidity, you need to keep them in shade with loose plugs for a week or two. Then you should transfer them to pots containing sterile soil and sand mixture. You can cover these pots with polybags. You can also precondition your rooted plantlets in different sucrose solutions (20- 30g/L of concentrations) before transferring to a potting mixture. This would increase the growth of shoots. In several studies, it is also suggested to add anti- transpirants like ' paclobutrazol ' in the rooting medium. This helps plantlets to have normal functioning of stomata, thickened roots and also reduces wilting. You need to customize these steps for each plant variety based on the plant's growth requirements.

13. Procedure for acclimatization; Remove the media from the plants by washing them with water Dip in the fungicide (2g/l) solution Transfer the plantlets to a potting mix, Covered it with polythene sheet to maintain humidity in it

14. Questions ????