Details

Title:

Physiological and Productive Responses of Native Perennial Grasses to Environmental Constraints in Mediterranean Environments

Author(s):

Copani, V., Cosentino, S.L., Testa, G., Virgillito, S., Scordia, D.

Document(s):

Abstract:

In the frame of OPTIMA project (Optimization of Perennial Grasses for Biomass production, 289642) four perennial grass species (Saccharum spontaneum spp. aegyptiacum, Sorghum halepense, Oryzopsis miliacea and Cimbopogon hirtus) were established at the Experimental Field of Catania University (Catania plain, 10 m a.s.l., 37°27'N, 15°03'E) in spring 2010 in a Mediterranean environment. Gas exchange measurements, using a gas exchange chamber (LICOR 6400 system, LI-COR Bioscience), have been carried out in the dry season between spring and summer 2012, therefore before the water stress (May), during water stress (June-July) and severe water stress (August), respectively, while productive measurements in winter 2011 and 2012. A long term plantation of giant reed managed in the same condition and grown in the same experimental field has been used as reference crop. Giant reed has been chosen as the reference crop since something is already known about this species regarding physiological traits in south Mediterranean environments. During the measurement time (May, June, July and August) the air temperature, relative humidity, intercepted PAR and soil moisture at 0-30, 30-60 and 60-90 cm were recorded. Cymbopogon and Oryzopsis behaved differently respect to giant reed, even though a decrease in net photosynthesis was observed from May to August. Before the water stress those two species reached 10 µmol CO2 m­ 2 -1-2 -1 s , while only 5 µmol CO2 m s during the severe water stress condition. Saccharum and Sorghum showed, instead, the same trend of the reference crop during the measurement time. Saccharum reached the highest value -2 -1 before the water stress (24-26 µmol CO2 m s ), while it was about two unit value lower than both Sorghum and -2 -1 giant reed during severe water stress (16 vs 14.5 µmol CO2 m s ). It is worth to mention that during the measurement of July and August the leaf temperature was close to 41 °C. Saccharum was the significantly highest yielding species both at the first and second year (9.8 and 18 t DM ha-1, respectively), while Sorghum, Cymbopogon and Oryzopsis were all not significantly different both at first and second year harvest (2.7 and 5.5 for Sorghum, 2.6 and 4.0 for Cymbopogon, 3.5 and 3.6 t DM ha-1 for Oryzopsis). These results show that there are significant differences among the wild perennial grasses both in terms of physiological and productive characters. Water and severe water stress lead to a reduced gas exchange of water transpired to the CO2 uptaken. Further studies need to be carried out to understand physiological mechanism of these new species.

Keywords:

transpiration, perennial grasses, mediterranean environment, net photosynthesis, wild species, WUE

Topic:

Biomass resources

Subtopic:

Energy crops and energy grasses

Event:

21st European Biomass Conference and Exhibition

Session:

1BV.3.15

Pages:

326 - 329

ISBN:

978-88-89407-53-0

Paper DOI:

10.5071/21stEUBCE2013-1BV.3.15

Price:

FREE