12818 - Vegetal Biology

Learning outcomes

At the end of the course the student will acquire the basic concepts of evolution of plant organism, plant cell and cell compartments, plant "phylosophy" in evolutionary terms, plant module structure, plant peculiar functions, of their role in the ecosystem and in the cycle of the elements that constitute the organic matter. Emphasis will be given to plant development, water balance and photosynthetic process; this will allow the full comprehension of the role of primary producers of autotrophic organisms in the ecosystem. The student will also be able to carry out a microscope  preparation from fresh (or dry) material and to identify the kind of plant, its growth stage, its environmental adaptations e the functions of the examined organs.

Course contents

Theoretical lessons

The student that follows the course of Plant Biology owns non-homogeneous cultural bases deriving from the high school. For this reason the first part of the course is focused on basic aspects of Biology and only later the course enters into the core of the topic.

Introduction (12 hours)

1)      An introduction to Botany: short history of Botany. Botany contributed to the progress of Biology. Plants have a different ‘phylosophy' than animals: autotrophy and eterotrophy. Why plants are important for men.

1)      Origine of life on Earth: Miller's experiment and exobiology. Prokaryotic (non-compartmented) and Eukaryotic (compartmented) cells. Appearance and evolution of photosynthesis.

2)      Composition of living matter. Water is the most abundant component. Inorganic substances are indispensables for plant metabolism. The elements C, H, O, N, P, S are present in organic substances. The main molecules of biological interest.

The living basic unit (15 hours)

1)      The living matter acquires new properties as individuals. The cell is the biological unit. The cell theory. The concept of relative surface.

2)      Eukaryotic plant cell. Biological membrane unit. Structure, composition and function of the cell wall. Primary and secondary metabolites and the osmotic role of the vacuole. Structure, function and localization of green (chloroplasts), colorless (leucoplasts) and colored (chromoplasts) plastids. The nucleus and the other organelles.

3)      Eukaryotic cells aggregate to form tissues. Embryonic and adult tissues. Covering, conductive, parenchymatic, supporting and secretory tissues.

Plant metabolism and reproduction (15 hours)

1)      Photosynthesis makes plants primary producers. The nature of light, the role of pigments. The z scheme describes redox reactions of the light phase. The dark reactions lead to sugar synthesis.

2)      Plant growth is regulated by chemical messengers: hormones. Chemical structure, biosynthesis sites and effects of the main plant hormones: auxin, cytokinin and gibberellins, which act by stimulating growth, and abscissic acid and ethylene, which favor senescence and stress response/defense.

3)      Plant water balance must be equilibrated. Water uptake and translocation, foliar evaporation and transpiration, stomatal role. Assimilate transport.

4)      Reproduction serves for species conservation and diffusion. Asexual and sexual re production. Mitosis and meiosis. Plant metagenetic cycles.

Practical/applicative lessons (18 hours)

The practical/applicative lessons (6 turns of 3 hours) consist of the observation at the optical microscope of hand-made thin sections obtained from fresh plants furnished by the Orto Botanico of the University. The sections can be easily observed with the only addition of water thanks to the presence of the plant cell walls. Plant material is observed at three further magnifications (10x, 100x and 400x) in order to appreciate more and more details.

1° turn: Observation of plant cells in the medullar dehydrated tissue of elder (Sambucus nigra L.), of chloroplasts in the green alga Spirogyra and in the aquatic plant Helodea, and of chromoplasts in carrot (Daucus carota L.)

2° turn: Observation of leucoplasts containing starch granules in potato tubers (Solanum tuberosum L.), maize (Zea mays L.) and bean seed (Phaseolus vulgaris L.) and Euphorbia latex.

3° turn: Observation of the structure (thin sections) of the dorso-ventral leaf of Edera, of the isolateral leaf of Pinus and of the parallel-venation leaf of Iris.

4° turn: Observation of the structure of the stem of a dicotyledonous (Helleborus) and a monocotyledonous (Ruscus) plant in their primary structure.

5° turn: Observation of the structure of the root of a dicotyledonous (Ranunculus) and a monocotyledonous (Iris) plant in their primary structure.

6° turn: Observation of the structure of the stem of a dicotyledonous (Liquidambar) and a gymnosperm (Tuja) plant in their secondary structure.

Readings/Bibliography

Mauseth J.D., Botanica (parte generale), Idelson-Gnocchi (II ed.) 

Speranza A. e Calzoni G., Struttura delle Piante in Immagini, Zanichelli

Smith et al. Biologia delle piante. Evoluzione, Sviluppo. Metabolismo, 2011, Zanichelli

Teaching methods

The course is subdivided in didactic units: the first, theoretical, is constituted by lessons accompanied by slides illustrating with pictures and schemes the notions to be given to the students. Given the small number of students (about 50) and the short time available, the teacher stimulates the students with questions in order to understand their basic level of preparation and to solicit their interest and possible clarifying questions. The second unit, Theoretical/practical, involves students personally since they have to fill an assessment questionnaire with 15 question with mulrtiple responses. Moreover, students themselves must prepare the material to be observed at the microscope. Students must also draw an outline that will testify the comprehension of the observed structure. With these simple operations the student will be able to recognize, given a part of a plant, what class (dicotyledonous or monocotyledonous), organ or tissues they are dealing with without any preliminary preparation.

Assessment methods

The assessment of the learning is carried out by a final examination that verifies the acquisition of the due knowledge through an oral examination that consists of generally of three questions regarding a) introduction aspects, b) citology and c) physiology. For the oral examination the score ranges from 0 to 30. The final score derives from the mean of the three scores. The examination is passed with at least 18/30. The duration of the examination is about 40 minutes.

Teaching tools

PC, projector, optical microscopy

Links to further information

http://www.scienzeagrarie.unibo.it/it

Office hours

See the website of Patrizia Torrigiani