93677 - Plant Biotic and Abiotic Stresses and Climate Change

Learning outcomes

At the end of the course, the student will acquire skills to identify the main disorders and alterations of plants and of their products caused by climate, weather and/or edaphic stressing conditions and to know the climate change influence on it. He will be able to identify the physiological and morphological modification induced by water, temperature, nutrient, light and pollution stresses that precede the appearance of the disorders.

Course contents

A) Prerequisites

Courses student need to have taken before: physics, plant biology, plant pathology, agricultural chemist and general agronomy. These basic and applied courses are provided in year 1 and 2 of the degree.

B) Teaching units

1. Introduction to the course (TUs 1 h)

Syllabus presentation and discussion, lectures, demonstrations, study visits, class material, contacts, final exam. Objectives and importance of the course within the degree and the profession of agricultural technician, with a particular emphasis on climate changes effects. Students suggestions and requests will be discussed.

2. Effects of climate change on plants and their microbiome, brief information about stress physiology (TUs 2 h)

Notes on climate changes with the greatest impact on agriculture (global warming, extreme weather events); effects of environmental conditions on plants; main strategies of the plants to adapt to the various environments and to their changes: main diagnostic methods of the stress disorders

3. Plant diseases caused by phytotoxic air pollutants ((TUs 3 h)

Notes on the main sources of pollution due to anthropogenic activities and possible consequences of the impact of phytotoxic air pollutants (IFA). Alteration of the quality of products and symptoms caused by the presence of the main pollutants. IFA indicator plants. Effects of pollutants on phytopathogenic fungi

Skills acquired:

The main air pollutants and their effect on plants

4. Temperature stress disorders (TUs 10 h)

Heat stress General aspects, effects on plants, resistance to heat, main disorders and alterations.

Chilling stress- General aspects, effects on plants, resistance to low temperatures, main disorders and alterations

Freezing stress - General aspects, effects on plants, resistance to negative temperatures, main disorders and alterations

Skills acquired:

Influence of high temperatures on alteration of plant physiological processes

Main adaptation strategies of the plants to high temperatures

Disorders induced by high temperatures

Plants susceptibility to chilling disorders depending on plant climate zones, cell membrane composition and ROS control.

Disorders induced by chilling and freezing in field and in storage conditions

Susceptibility of plants to freezing disorders

Plants acclimatation strategies to frost

Passive and active methods to prevent frost damage

The effects of cold on the biological cycle of pathogens

5.Water stress disorders (TUs 6 ore)

Water deficit general aspects, effects on plants, resistance to drought, main disorders and alterations

Water saturation and flooding (lack of O2) General aspects, effects on plants, resistance to flooding, disorders

Skills acquired:

Mechanisms of drought tolerance in plants

Main disorders and alterations induced by water deficit

Influence of drought stress on plant susceptibility to diseases

Effects of low relative humidity on postharvest life of fresh plant products

Influence water saturation of the soil on plants anoxia stress

Main disorders and alterations of roots in water saturated soils

Tolerance to flooding of the main crops

6. Light stress disorders (TUs 3 h)

Photoperiodism, short day, long day and day neutral plants; abnormal day length effects on some plants (bloom, growth, productivity). Effects of light deficiency: etiolation, whitening (blanching) and shading. Effects of light intensity and wavelength. Effects of UV C on plant disease resistance. Greening of root crops and potatoes and build up of toxic glycoalkaloids.

Skills acquired:

Influence of photoperiod on life and productivity of plants

Main disorders and alterations induced by light deficiency and abnormal wavelength

7. Nutritional stress disorders (TUs 6 h)

Brief information about mineral nutrition definition of nutrients and their activity, healthy condition, nutrient mineral elements, macro and micro nutrients. Definition of nutrient deficiency, Liebig’s law, root absorption, mineral interaction, chronic and acute deficiency. Diagnosis of nutrient deficiency, symptoms,

tissue and soil analysis. Main disorders caused by N, P, K, Ca, Fe deficiency. Influence of mineral elements on diseases. Management of plant nutrition.

Skills acquired:

Importance and influence of mineral nutrition on growth and plant health

Main methods and technics for the diagnosis of mineral deficiency in plants

Main disorders induced by nutrients deficiency

Effects of mineral deficiency on susceptibility to biotic diseases

8. Effects of climate on pathosystems (TUs 3 h)

Changes in the distribution ranges, virulence variation of pathogens, modification of the disease gradient, mutation of some individuals of the population, introduction and adaptation of alien species.

Skills acquired:

The effects of climate on pathosystems and the risk of introducing new alien pathogenic species in new continents

9. Exercises (TUs 6 h)

Specialized seminars are organized with experts in the sector (eg on pathologies of the vine) with particular reference to abiotic stress. A study visit to research centers and biomonitoring stations is organized to show students the impact of stress diseases on the working world through case studies, applied diagnostic techniques and prevention methods

Readings/Bibliography

Taiz. L, Zeiger E. (Translated by Maffei M.) Fisiologia Vegetale. Piccin Nuova Libraria SpA. Padova, 2006. Only chapters: 5 - La nutrizione minerale e 26 - Fisiologia dello stress. (also at Biblioteca centralizzata G. Goidanich).

Additional readings:

Shurtleff C.M., Averre W.C. The plant disease clinic and field diagnosis of abiotic diseases. APS press, St. Paul, Minnesota, 1997

Teaching methods

The course is divided into two teaching modules:

1) Classroom lectures with power point presentations visualizing diagrams, figures, outlooks. Student’s discussion, curiosity, and critical thinking on plant stress and the causing agents is stimulated. Their progresses and hurdles will be informally assessed through the talks.

2) Exercises and study visit, see 9

Assessment methods

The knowledge acquired in this course is assessed via a written examination. It consists of  quizzes and open-ended questions, referring to the entire course program.  Students are assessed on at least 4 teaching units. The aim of the evaluation is to assess the overall capacity of the student to address problems areas in the field of environmental disorders and biotic stress due to climate change and their control and to recognize the symptoms on the main crops.

Teaching tools

PC, video-projector, Teams, plant parts damaged by environmental stress. Study visit.

Office hours

See the website of Antonio Prodi