Environmental stress has regulated the function, morphology, and diversity of cells, organs, individuals and plant communities. The interaction of plants with the stress-inducing environments has produced in the plants a set of adaptive responses that can be studied in different description scopes: from organelles and subcellular structures to the level of plant communities. When it occurs for short time or low intensity, environmental stress can induce hardening, followed by induction of tolerance; on the other hand, when the plant´s reaction is for a long time or responding to a significant stress intensity, the response of plants includes decreased growth, depletion of metabolic reserves and loss of productivity and yield, even reaching the death of plants. Current knowledge about these crop responses can be translated into agronomic practices aimed at mitigating the adverse effects of environmental stress. This chapter will present the mechanisms of response and adaptation of crop plants to the environmental factors that most commonly cause crop damage or yield loss: high and low temperature, salinity, water deficit and nutrient deficits. Agronomic practices aimed at modifying or balancing some of the environmental factors involved and the use of tolerance induction techniques are described.
Part of the book: Plant, Abiotic Stress and Responses to Climate Change
Fusarium oxysporum causes vascular wilt disease in a broad range of crops, including tomato (Solanum lycopersicum). Tomato, a major and important vegetable crop, is susceptible to F. oxysporum f. sp. lycopersici (FOL), a biotrophic pathogen that is the causal agent of tomato wilt resulting in significant yield losses each year. Development of disease in susceptible tomato plants requires FOL to advance through a series of transitions, beginning with spore germination and culminating with establishment of a systemic infection. In addition, many host attributes, including the composition of root exudates, the structure of the root cortex, and the capacity to recognize and respond quickly to invasive growth of a pathogen, can impede the development of FOL. FOL divides into races on the basis of the ability of individual strains to overcome specific genes. This implies the presence of avirulence genes (Avr) in the fungus that is recognized by products of the corresponding genes. In tomato, resistance (R) genes against the wilt-inducing FOL are called immunity genes, and the interaction between these genes will determine the success of the infection.
Part of the book: Fusarium
Iodine, silicon, and selenium are considered elements not essential for the metabolism of plants. However, these elements are vital for humans, and their presence as traces in food is beneficial. The use of I, Si, and Se in the fertilization programs of the plants allows, on the one hand, the mineral biofortification of the crops and, on the other hand, through mechanisms not yet fully understood, the production and accumulation of more antioxidants in the edible organs. This chapter provides an overview about the use of I, Si, and Se both for mineral biofortification and for the increase in the concentration of antioxidants in plants, with an emphasis on redox metabolism adjustments and antioxidant chemical species studied. The scope of the chapter is on horticultural species in the open field and under greenhouse or tunnels.
Part of the book: Antioxidants in Foods and Its Applications