al toxicity tolarence fi

Mahesh R Hampannavar 1

Wel come


MAHESH R HAMPANNAVARPG14AGR6062Jnr M.Sc

Aluminium Toxicity Tolerance


Contents

• Introduction

• Al-toxicity symptoms in plants

• Site of al accumulation

• Injury mechanisms

• Genetics of Al Toxicity Resistance

• Sources Mineral Toxicity Resistance

• Creation of mineral toxicity environment

• Selection criteria Al resistance

• Characters associated Al toxicity resistance

• Al toxicity resistance varieties

• conclusion


Introduction

• Micro element but not essential element• Al toxicity-soil low pH<5.0• Free Al ions soluble in low pH• in Acidity soil-Fe,Mn,Al toxicity found• Mn toxicity and deficiency of P,Ca,Mg also

interplay in manifestion of Al toxicity


Al-TOXICITY SYMPTOMS IN PLANTS

• Poor or stunted growth• Leaf tip death and marginal chlorosis• Deficiency symptoms of Fe,Ca• Effect on leaf area ,chlorophyll content and Hill

activity• Stunted and deformed roots- it become

stibbier and thicker ,low specific surface• Lateral root thickened and turn brown• Callose formation


SITE OF Al ACCUMALATION

• Primary accumalation in Root maristem

• At cellular level in cell wall and nucleus

• Specific site is cellular membrane of younger

and outer root cells


INJURY MECHANISMS

Reduced root growth-• Main effect…• Inhibits cell division in root meristem and

cell elongatin…• Decrease extensibilityby cross linking

protien in middle lamella…• Increase viscocity of protoplasm..• Inhibition of DNA synthesis…


• Effect of Al-toxicity on nutrient uptake-Ca,Mg,P,Fe and NO¯³ deficiency

• Al toxicity affects pollen germination• Chromosomal abnormality and reducesed

DNA synthesis • Effect of Al toxicity on cell and cellular

components- damaged cytoplasm,disruption of golgi bodies , extesive vacuoleation,cell distortion,cytoplam density


Genetics of Al Toxicity Resistance

• Generally polygenic trait• Monogenic in Barley,Maize

• MAIZE - Lte2• BARLEY- Alp


GENETICS OF Al TOXICITY RESISTANCE

CROP GENETIC CONTROL HERITABILITY

REMARKS

BARLEY Alp -- --

WHEAT 5AL,6A,2DL,4DL,4BL,5D,7D -- --

RYE 3R, 4R,6R

-- supressed when intercross with wheat

MAIZE Single gene with multiple alleles:pleotropic effect of Lte2

-- Lte2 specifies heat

SORGHUM polygenic high Selection would be effective

ALFALFA polygenic -- --


Sources Mineral Toxicity Resistance

• Old varieties adopted to acid soil and mineral toxicity

• Cultivated varieties bred and cultivated in acid soil region

eg- Brazalian wheats


Creation of mineral toxicity environment

• Field having mineral toxicity

• Pots filled with problem soil

• In nutrient solution –based on hydrophonics or sand culture


Selection criteria Al resistance

• Shoot dry matter - in pot and nutrient culture

• Root length-

• Root wieght- In hydrophonics• Root deformation • Root discolouration


• Al exclusion from roots-Eg- In wheat, stained with haematoxylin,donot

take up stain are resistance• In field expt- yield is used to measure the

resistance , evaluate in normal and stress condition,it suited for parents and F1


Characters associate with Al toxicity resistance

• Plant raise pH of their rhizosphere• Al excluded from entering root from mucilage• Al compartmentalized in roots –chelation of

organic acid in root• Al accumalation in older leaves eg-tea• Al resistance involve nutritional aspect-NH⁺4,

NO⁻3,Ca deficiency,P deficiency


Problems in Al toxicity resistance breeding

• Toxicity profile varies with location • Specific Al resistance may not serve the

purpose• Al toxicity interact with other mineral Ca,Mg,P

so care should be taken during selection• Hydrophonics is expensive and skill required• Double work load- stress and non stresse

condition evaluation


Al toxicity resistance varieties

• Rice- IR-64, Basmati370,Atlas66,IR-24• Wheat- BH1146,kedett• Maize- sikuni,B37,C525-M• Sorghum-PaB8A,B37• Barley-Aura• Soybean-No.62,Lachang• Groundnut-TAG-24,TCGA-5,-6,-10,-34,JL-220


CONCLUSION


Thank you one and

All

al toxicity tolarence fi

Science

introduction micro element

plants site