Allelopathy

general description about the allelopathy and allelochemistry with respect to agroforestry. Also, includes methods to study the allelopathy.

1. ALLELOPATHY Presented by Gajendra C.V

2. Allelopathy – Meaning and definition Coined by Hans molisch (1937), In Greek, Allelo and Pathos literally Mutual suffering Definition: Allelopathy as any direct or indirect positive or negative effect of one plant on the other (including the microbes) through the release of chemicals into the environment

3. Allelopathy perspectives and problems Lack of adequate field studies Difficulties in determining the critical concentrations of allelo -chemicals in soil Inappropriate bio-assay models Difficulty in establishing the role of microbes in litter decomposition, release of allelo -chemicals and subsequent transformation

4. Roles of microbes in modulating the interaction of allelopathic donor-receiver species Marsmin

5. Allelochemicals – Diversity , Nature, Mode of Release and Significance In, general the chemicals responsible for the phenomenon of allelopathy is called allelochemicals Allelopathic classes of chemical interactions Antibiotic - (Microorganism to Microorganism Koline - (Plants to Plants) Marsmin – (Microorganisms to Plants) Phytoncide - (Plants to Microorganisms) Based on type of donor Plant eco-chemicals ( Sapro - inhitors and phyto – inhibitors) The plant phenolics and Terpenoides show great chemical diversity

6. Nature These phytochemicals synthesized as 2 metabolites – have no direct effect function in growth and development of plant - Defensive adapation

7. Release of allelo -chemicals Lechation Volatilization Root exudates Decomposition of plant parts

8. Induction of allelochemical production by the plant itself and environmental factors Plant factors Environmental factors Biotic factors

9. Methods study the Allelopathy Plot box method Sandwich method Stair-step method Revised substitutive design (to descriminate the allelopathic contribution o field condition) New sloped box method ( allelopathy under competitive interactions) A dish pack method (Volatile allelo -chemicals )

10. A New sloped box method to study allelopathic effects of Acacia dealbata under competitive interactions (Lorenzo et al. , 2012)

11. A dish pack method - (Fang Cheng and Zhihui Cheng, 2015)

12. Major pathway leading to production of allelochemicals – (Wang et al., 2006 ) Shikimmic acid pathway, Acid mevalanonate pathway

13. Chemical Warfare in the Plant Kingdom Allelopathic Species Type of Chemical Affected Species Sugar Maple Phenolics Yellow Birch, White Spruce Hackberry Coumarins Herbs, grasses Eucalyptus Phenolics Shrubs, herbs, grasses Black Walnut Juglone (Quinone) Pines, Apple, Birch, Black Alder, Hackberry, Basswood, Azalea , Juniper Phenolics Grasses Sycamore (Planetree) Coumarins Yellow Birch, herbs, grasses Black Cherry Cyanogenic glycosides Red Maple, Red Pine Oaks Coumarins , Herbs, grasses Other phenolics     Sassafras Terpenoids Elm, Silver Maple, Boxelder Balsam Poplar   Green Alder Southern Red Oak   Sweetgum

14. Allelopathic problems associated with Agriculture, Horticulture and Forestry Soil sickness Auto toxicity under same crop mono - cropping . Increased crop- weed interference Growing susceptibility of plants to disease/ pests Reduced nitrification and biological nitrogen fixation Reduced nutrient uptake Weed seed decomposition delayed/ prevented Poor success on replanting of tree crops Failure of vegetative propagation (e.g. grafting, budding) Suppression effect from trees

15. Recommendation Application of allelopathy in sustainable developmental agriculture, especially as natural herbicide and pesticide models

16. 2 nd AFRICA - INTERNATIONAL ALLELOPATHY CONGRESS Topics Allelopathy in sustainable and organic agriculture Allelopathy in natural ecosystems Allelopathy in soil sickness Chemistry of alleochemicals Molecular biology and genetics of allelopathy Physiology and biochemistry of allelopathy Allelopathy mechanisms and interactions Alleopathy methodologies and modelling Allelopathy for sustainability November 16 th -19 th ,2016 Tunisia

17. Thank you….