Heat

Cold Heavy metal

SaltDrought

Flooding

Introduction to Abiotic StressesEffect on crop plants

Plant responseBreeding strategies

Dr. Shailendra SharmaGenetics and Plant Breeding

Part 1

All the non-living environmental factors that can negatively oreven harmfully affect the growth and productivity of plants andhence reduced crop yields•Drought/moisture• Extreme temperature (heat, cold/chilling)•Salinity/alkalinity/sodicity•Flooding/waterlogging/submergence•Soil factors•Mineral toxicity•Nutrient deficiency•-------------With increasing challenges posed by increasing population andextreme weather conditions change, it is predicted that drasticclimate changes will become even more frequent and severe,further reducing crop yields, especially in the tropics andsubtropics.

Drought stress can be simply defined as a shortage of water

which induces morphological, biochemical, physiological, and

molecular changes.

It is one of the consequences of climate change that has a

negative impact on crop growth and yield.

All of these changes reduce plant growth and crop production

among the most important cereal crops.

Drought stress can occur at any growth stage and depends on the

local environment.

Drought

Heat StressHeat stress causes a series of changes that adversely affect plant development.

At high temperatures, enzyme functions can be disrupted with irreversibledenaturation of proteins (Howarth 2005).

If temperature rises to extreme levels, severe cellular injuries may occurfollowed by immediate cell death within a few minutes (Howarth 2005 ;Schofflet al. 1998 ).

Slower heat injuries include loss of membrane integrity, inhibition of proteinsynthesis, enzyme inactivation in chloroplasts and mitochondria, and proteindegradation (Howarth 2005).

Heat stress also affects cell cycle & cell division through changing themicrotubules organization (Smertenko et al. 1997 ).

These injuries together cause starvation, growth inhibition, decreased ion flux,accumulation of toxic compounds & ROS (Howarth 2005 ;Schoffl et al. 1998 ).

High temperature leads to modification of membrane properties, and liquidviscosity inside plant cell organelles (Źróbek-Sokolnik2012).

The increased fluidity of membrane lipids, and protein denaturation andaggregation are immediate injuries occurring after exposure to hightemperature (Howarth 2005 ).

Soil salinity is one of the most serious factors limiting productivity of

agricultural crops.

In soil containing high amount of salts, plant uptake higher concentration of

soluble salts that negatively affect the uptake of water through the root system

due to higher osmotic pressure.

Limited water in plant cells influences its turgidity and ultimately changes the

membrane stability (Sairam et al, 2002).

Salt stress is known to affect the seed germination, plant growth, water deficit,

ion imbalance and cause several biochemical lesions in various plants.

Sodium chloride (NaCl) is the most predominant salt in saline soil which

increases the concentration of Na+ and Cl- level in the soil, and affects the

uptake of essential nutrients like Ca++, Mg++ and K+ by the plants and

subsequently increases the uptake of Na+ and Cl- in susceptible plants(Khan et

al, 1999).

Salinity

Plants 2019, 8, 34; doi:10.3390/plants8020034

Plants 2019, 8, 34; doi:10.3390/plants8020034

Predicted national-scale yield loss for maize, rice, wheat and soybean averaged from 1950-2000

Predicted national-scale yield loss for maize, rice, wheat and soybean averaged from 1994-2010

Predicted national-scale yield loss for maize, rice, wheat and soybean in 2009

Number of large flood events from 1985 to 2010

Paths to increased crop yield in suboptimal environments

Targets for improving the efficiency of photosynthesis and primary carbonmetabolism that have experimental support for success. Transgenic manipulations ofphotosynthetic metabolism that lead to improved photosynthetic efficiency.

Abiotic stress response in plants

From: Chapter 9 by Geoffrey Onaga and Kerstin WydraAdvances in Plant Tolerance to Abiotic Stresse (http://dx.doi.org/10.5772/64350)

Loredana F. Ciarmiello, Pasqualina Woodrow, Amodio Fuggi, Giovanni Pontecorvo and Petronia Carillo (2011). Plant Genes for AbioticStress, Abiotic Stress in Plants - Mechanisms and Adaptations, Prof. Arun Shanker (Ed.), ISBN: 978-953-307-394-1, InTech, Available from:http://www.intechopen.com/books/abioticstress-in-plants-mechanisms-and-adaptations/plant-genes-for-abiotic-stress

Wang et al. (2003) Planta 218: 1–14 (DOI 10.1007/s00425-003-1105-5)

The complexity of the plant response to abiotic stress

Stress sensing and signaling in different cell organelles

(For details consult: He et al. (2018) Frontiers in Plant Science Article Volume 9 Article: 1771)

The general defense systems and the underlying regulatory network in botanic responsesto abiotic stresses

Physiological, biochemical, and molecular basis ofdrought stress tolerance in plants

From: Chapter 9 by Geoffrey Onaga and Kerstin WydraAdvances in Plant Tolerance to Abiotic Stresse (http://dx.doi.org/10.5772/64350)

Plants 2019, 8, 34; doi:10.3390/plants8020034

Plants 2019, 8, 34; doi:10.3390/plants8020034

Plants 2019, 8, 34; doi:10.3390/plants8020034

Plants 2019, 8, 34; doi:10.3390/plants8020034

Plants 2019, 8, 34; doi:10.3390/plants8020034

Sairam, Raj Kumar & Rao, K.Veerabhadra & Srivastava, G. (2002) Differential Response of Wheat Genotypes to Long Term Salinity Stress in Relation to Oxidative Stress, Antioxidant Activity and Osmolyte Concentration. Plant Science. 163. 1037-1046. 10.1016/S0168-9452(02)00278-9.

Howarth, C. J. (2005) “Genetic improvements of tolerance to high temperature,” in Abiotic Stresses: Plant Resistancethrough Breeding and Molecular Approaches, eds M. Ashraf and P. J. C. Harris (New York, NY: Haworth Press Inc),277–300.

Schöffl, F., Prändl, R., and Reindl, A (1998) Regulation of the Heat-Shock Response Plant Physiol. 117, 1135–1141. doi:10.1104/pp.117.4.1135

Smertenko A, Draber P, Viklicky V, Opatrny Z (1997) Heat stress affects the organization of microtubules and celldivision in Nicotiana tabacum cells. Plant, Cell and Environment (1997) 20, 1534-1542

Źróbek-Sokolnik A. Temperature stress and responses of plants. In: Environmental adaptations and stress tolerance ofplants in the era of climate change. Ahmad P, Prasad MN V, editors. New York, NY: Springer New York; 2012. p. 113–134.

References

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Shailendra Sharma