B1830 - Biochemistry of Soil/Plant Interaction

Learning outcomes

At the end of the course the student knows the chemical and biochemical processes that regulate the soil-plant interaction; he is able to understand, at the molecular level, the mechanisms that regulate the activity of the soil surfaces, of the soil-plant interfaceroot, the processes that govern the radical absorption of the elements, the processes that regulate the mobility of nutrients from the colloidal surfaces of the soil through the simplasto and apoplasto.

Course contents

BIOCHEMISTRY OF SOIL-PLANT INTERACTION

(Master's Degree in Plant Agricultural Biotechnology)

MODULE 1. SOIL BIOCHEMISTRY (30 hours – Dott.ssa Martina Mazzon)

1.1 Soil constituents (4 hours)

Mineral constituents (minerals, silicates, phyllosilicate structure, oxides and hydroxides, carbonates).

Organic constituents: organic matter, classification and outline of transformation and stabilization processes.

1.2 Physical and chemical properties of the soil (4 hours)

Surface properties (specific surface area and origin of charges), adsorption and ion exchange.

Soil reaction: definition of soil pH, active and exchangeable acidity, soil classification based on pH, pH and nutrients.

1.3 The microbial component (12 hours)

Microorganisms in soil: microbial biomass and microbiome-plant interactions, activity, respiration and microbial-functional indices

Soil enzymes: definition, classification, localization and enzymatic catalysis.

Enzymes involved in the carbon, nitrogen and phosphorus cycles: definition of the main enzymatic activities and their interpretation.

Enzymes as indicators of soil quality: environmental factors, enzymes and detoxification, determination and interpretation of related indices.

1.4 Analytical procedures and interpretation of results (10 hours)

Analytical methods for the determination of: soil reaction (pH), total limestone, carbon and nitrogen (extractable and microbial), available phosphorus.

MODULE 2. SOIL-PLANT INTERACTION (30 HOURS – Prof. Claudio Marzadori)

2.1 Nutrients and short distance transport (6 hours)

Soil fertility and the threats that undermine it

The essential nutrients in soil and the concept of NUE

Mechanisms of short-distance radical transport and absorption: biochemical and molecular aspects

2.2 Availability and mobility of nutrients in the soil (8 hours)

Chemical properties of soil and factors affecting nutrients mobility

Main transport mechanisms of nutrients in the Bulk Soil and in the rhizosphere

Radical strategies to increase the absorption of elements that are not very mobile

Introduction to the concept of rhizosphere

2.3 Rhizo-depositions and chemical properties of the rhizosphere (8 hours)

Definition of rhizosphere

Rhizodepositions: qualitative and quantitative aspects

Effects of rhizodepositions on rhizosphere formation

Chemical properties of the rhizosphere, regulation of rhizospheric pH and ion mobility in the rhizosphere

Management of rhizosphere properties and nutrients availability

2.4 The fundamental nutrients (8 hours)

The nitrogen cycle in the soil and root uptake: biochemical and molecular aspects

Soil phosphate and root uptake of phosphate: biochemical and molecular aspects

Soil iron and iron uptake strategies: biochemical and molecular aspects

Readings/Bibliography

Slides of the lessons that will be uploaded at the beginning of the course and materials provided by the teachers

Teaching methods

The course is organised into in-person lectures supported by multimedia presentations, conceptual diagrams, explanatory figures, and supplementary bibliographic material.

The teaching activities are designed to promote understanding of the biochemical and nutritional processes that regulate the functioning of the soil–plant system, highlighting the relationships between plant metabolism, nutrient availability, and nutrient uptake in agricultural and forest ecosystems.

Assessment methods

Assessment for the course Biochemistry of Soil/Plant Interaction is carried out through a final oral examination, conducted jointly for the two modules that make up the course. The oral examination will cover the topics addressed in the lectures of both modules. At least two basic questions will be asked, one for each thematic area relating to the two modules. Starting from this structure, further discussion of the topics covered may follow, where deemed necessary.

Assessment criteria

18–19: essential knowledge of the fundamental topics; limited ability to make connections between the different processes and acceptable use of scientific terminology.

20–24: adequate knowledge of the topics covered; ability to correctly describe the main processes and to make simple connections between soil properties, plant nutrition and metabolism.

25–27: good knowledge of the topics; ability to integrate the different aspects of the course and to correctly interpret the relationships between soil, plant and environment.

28–30: in-depth and critical knowledge of the course content; ability to effectively connect the chemical, biochemical and nutritional processes that regulate the functioning of agricultural and forest ecosystems; full command of the subject-specific language.

30 with honours: excellent preparation, ability to process information independently and provide critical synthesis, rigorous use of scientific terminology, and ability to discuss in an integrated and in-depth manner the relationships between soil fertility, plant metabolism, productivity and sustainability.

With regard to assessment, the use of generative Artificial Intelligence is not applicable to the in-person oral examination. Any preparatory materials produced using AI tools remain the student’s responsibility and do not replace the necessary independent acquisition of the knowledge required to pass the examination.

Students with Specific Learning Disorders, or with temporary or permanent disabilities, are invited to promptly contact the relevant University office in order to agree on any adaptations to the examination, in compliance with the learning objectives of the course.

Teaching tools

Slides provided by the teachers and teaching laboratories present at the teaching site

Office hours

See the website of Claudio Marzadori

See the website of Martina Mazzon