Corso di Laurea Magistrale in Scienze viticole ed enologiche - SVE

 To learn about the relationships between grapevine physiology and inputs from agriculture practices, upon both cultivation standards and abiotic limiting conditions.

The students will integrate the knowledge acquired both by following the course programme and by examining scientific literature.

Recorded movies of the lessons on line on MOODLE platform

Until the COVID restrictions continue, the exam will be carried out entirely in oral form by presenting at the date and time of exam scheduling to the WEBEX virtual room.

https://unito.webex.com/meet/claudio.lovisolo

1) General overview of the grapevine physiology

Water metabolism: physiological role.

Concept of water potential as an energy index.

2) Measurement of water potential: in the leaf, in the shoot, pre-dawn, at mid-day.

The analogy of the Ohm Law to study water fluxes in plant.

The continuum of water flow along soil-plant-atmosphere.

How to modelize hydraulic resistances in grapevine organs.

Implication of cell water metabolism on grapevine water balance:
osmoregulation; symplasm/apoplasm water exchange; aquaporin role.

3) Time scaling relationships between water potential and transpiration:
occurrence of water stress; occurrence of rain; diel fluctuations; seasonal fluctuations; in different water-holding soils.

Plant water balance:
isohydric response to water stress, connection with pre-dawn water potential;
anisohydric response, connection with stem water potential.

4) Measurement of hydraulic conductance (in the root, in the shoot, in the leaf, in the whole plant).

The evaporative flux method to estimate hydraulic resistances in grapevine organs.

The high-pressure-flow-meter:
principles;
measurements of embolism extent;
estimation of aquaporin role in controlling plant hydraulics.

Root water absorption and transport:
symplasm, apoplasm and cell-to-cell water pathways;
hormonal control at budbreak;
soil temperature and seasonal control.

5) Abscisic acid biosynthesis in root:
activation by pH; influence of water stress; influence of root respiration; split-root experiments and partial root drying.

Abscisic acid root-to-shoot control:
implications in rootstocks;
auxin/ABA interaction for root deepening and later root emergence;
soil properties (clay) modulate ABA response.

Water transport in rootstocks:
induction of tolerance to water stress (mechanisms and genotypes related);
Induction of stress avoidance (mechanisms and genotypes related);
hormonal control of aquaporin activation;
vigor induction and water metabolism.

6) Auxin control of vascular development.

Model of auxin translocation:
auxin control on apex dominance in grapevine;
auxin control on tropisms in grapevine.

Xylem conductivity in relation to upward and downward shoot growth orientation.

Water (sap) transport in the shoot:
embolism formation;
embolism refilling;
role of aquaporins;
hormonal control of aquaporin activation.

 7) Transpiration :

the vapor pressure deficit (VPD) as energy determinant.

Atmospheric demand of transpiration.

Kinetics of temperature and relative humidity.

Stomatal opening and closure (physiology of guard cells).

8) Environmental control of transpiration (microclimatic influences and viticultural issues).

Stomatal control (regulation during water stress and CO₂ feedbacks).

VPD influence on ABA catabolism. ABA hydroxylases.

Optimization of gas exchange to current environmental conditions (Speirs et al 2013 JXB, Soar et al 2006 AJGWR)VPD/ABA Involvement in controlling embolism repair (Perrone et 2012 Planta)

9) Photosynthesis; Photorespiration; Photoinhibition.

Limitations to photosynthesis in grapevine:
water stress;
stomatal regulation;
light deficiency;
light excess;
temperature.

10) Limitations to photosynthesis in grapevine:
leaf ageing;
in sun and shadow leaves;
sink sucrose downloading (phloem);
starch accumulation in leaf.

Recovery from drought : dependence on belowground sink control

11) Measurements of leaf gas exchange:
the infra-red gas analyzer.

12) Measurement of leaf chlorophyll fluorescence. 
Discrimination against 13C during water stress.

Keller M. The Science of Grapevines: Anatomy and Physiology, Elsevier Academic Press, 2010.

The book is on line for students via Bibliopass agrovet unito

for further details:

Taiz, Zeiger. Plant Physiology, Piccin http://6e.plantphys.net

Until the COVID restrictions continue, the exam will be carried out entirely in oral form by presenting at the date and time of exam scheduling to the WEBEX virtual room.

https://unito.webex.com/meet/claudio.lovisolo