STEM AND ROOT WOOD ANATOMY OF THE SHRUB PHLOMIS FRUTICOSA (LABIATAE)

IAWA Journal ◽  
2004 ◽  
Vol 25 (1) ◽  
pp. 71-77 ◽  
Author(s):  
G.K. Psaras ◽  
I. Sofroniou

Wood from the stems and roots of the malacophyllous Mediterranean drought semi-deciduous species Phlomis fruticosa was studied. The stem is diffuse-porous with narrow vessels. Though narrow vessels impose high conducting resistance, they are less vulnerable to cavitations, thus providing safety during summer drought and winter freezing. The geographical distribution of the plant (up to 1400 m altitude) may be relevant to the occurrence of narrow stem vessels, which provide high resistance to cavitations from low temperatures during winter. Vessel grouping in the stem adds to the safety against cavitations. Root vessels are mostly solitary and have almost double the diameter of stem vessels. Diffuse-porosity, the presence of narrow vessels in stems and the values of vulnerability and mesomorphy indices, are adaptations to the two stresses imposed by the Mediterranean climate, i.e. summer drought and winter cold.

2005 ◽  
Vol 95 (11) ◽  
pp. 1279-1286 ◽  
Author(s):  
E. Gamliel-Atinsky ◽  
D. Shtienberg ◽  
H. Vintal ◽  
Y. Nitzni ◽  
A. Dinoor

Temperature and wetness conditions required for development and maturation of Didymella rabiei pseudothecia were determined in a series of experiments conducted in controlled-environmental conditions. Initial stages of pseudothecium formation occurred at temperatures ranging from 5 to 15°C. Incubation at low temperatures was essential for subsequent pseudothecium maturation. This requirement was satisfied for chickpea stem segments incubated at 5 or 10°C for three consecutive weeks or during periods of 3 or 5 days, separated by periods at higher temperatures. Following the low-temperature requirement, subsequent pseudothecium development was independent of temperature in the range tested (5 to 20°C). Wetness was essential for pseudothecium production: pseudothecia formed and matured on stem segments maintained continuously wet but also on those exposed to periods of three or five wet days, separated by dry periods. The dispersal of D. rabiei ascospores was studied using chickpea plants as living traps in the field. Trap plants were infected mainly when exposed during rain but also in rainless periods. Results of this study enabled us to describe the developmental events leading to the production of the teleomorph stage and the dispersal of ascospores by D. rabiei in the Mediterranean climate of Israel.


IAWA Journal ◽  
1999 ◽  
Vol 20 (4) ◽  
pp. 419-429 ◽  
Author(s):  
G.K. Psaras ◽  
I. Sofroniou

Root and stern wood of the Mediterranean summergreen Capparis spinosa L. was studied. Wood anatomical features favour high hydraulic conductivity, which is necessary for maintaining the high midday stomatal conductance and rates of photosynthesis observed in this plant. Xylem conduits of both stern and root consist of wide and short vessel elements with simple perforation plates. Vessel grouping in the stern secures xylem safety against cavitations. The plant would be highly vulnerable to cavitations due to freezing conditions, although these are rare during the Mediterranean winter. Thus, the anatomical features of the plant, which does not seem to suffer from water stress though growing entirely during the Mediterranean summer drought, are compatible with its adaptive strategy. The significant amount of minerals found in the root vessels, and the abundant starch grains of the wood might be involved in a possible osmotic shifting of water in the xylem.


Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 679
Author(s):  
Danilo Scordia ◽  
Giovanni Scalici ◽  
John Clifton-Brown ◽  
Paul Robson ◽  
Cristina Patanè ◽  
...  

Predictions of future climate scenarios indicate that yields from perennial biomass crops (PBCs) growing in the Mediterranean region are likely to decline due to prolonged drought. Among PBCs, Miscanthus grasses with C4 photosynthesis combine high yield potentials and water use efficiencies. However, the standard commercial clone M. x giganteus (Mxg), with minimal stomatal regulation, is too sensitive to drought for reliable yields in the Mediterranean regions. This paper screened a diverse panel of thirteen Miscanthus genotypes (M. sinensis, M. floridulus, M. sacchariflorus and Mxg) to identify which types could maximize yield under summer drought conditions typical in the South Mediterranean climate. In the second growing season, significant differences were observed for plant height (from 63 to 185 cm), stem number (from 12 to 208 stems plant−1), biomass yield (from 0.17 to 6.4 kg DM plant−1) and whole crop water use efficiency (from 0.11 to 7.0 g L−1). Temporal variation in net photosynthesis, stomatal conductance, transpiration rate and instantaneous water use efficiency identified different strategies adopted by genotypes, and that genotypes selected from M. floridulus and M. sinensis were better adapted to rainfed conditions and could produce six times more biomass than the Mxg. These accessions are being used as parents in experimental breeding aimed at producing future seed-based drought resilient hybrids.


1989 ◽  
Vol 35 ◽  
pp. 1-19 ◽  
Author(s):  
Graeme Barker

Stock-keeping in the Mediterranean has to be adapted to the fundamental characteristics of the Mediterranean climate (mild wet winters and hot dry summers) and to the distinct variations in soil type and plant growth at different altitudes. The natural vegetation of the coastal regions is dominated by plants that can withstand the summer drought (when temperatures average 70–80 degrees F) such as the olive, holm oak, cork oak, and macchia scrub. The lowland pastures are green and succulent from autumn to spring, when temperatures average 45–55 degrees F and rainfall is relatively abundant, but are withered and of little nutritional value in the summer. In the interior mountains of Spain, Italy, and Greece, average January temperatures are below freezing and snow covers the highest regions through the winter months, but there is extensive grazing of excellent quality from the late spring to early autumn.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3313
Author(s):  
Juan Luis Aguirre ◽  
María Teresa Martín ◽  
Sergio González ◽  
Manuel Peinado

The effects of two types of biochar on corn production in the Mediterranean climate during the growing season were analyzed. The two types of biochar were obtained from pyrolysis of Pinus pinaster. B1 was fully pyrolyzed with 55.90% organic carbon, and B2 was medium pyrolyzed with 23.50% organic carbon. B1 and B2 were supplemented in the soil of 20 plots (1 m2) at a dose of 4 kg/m2. C1 and C2 (10 plots each) served as control plots. The plots were automatically irrigated and fertilizer was not applied. The B1-supplemented plots exhibited a significant 84.58% increase in dry corn production per square meter and a 93.16% increase in corn wet weight (p << 0.001). Corn production was no different between B2-supplemented, C1, and C2 plots (p > 0.01). The weight of cobs from B1-supplemented plots was 62.3%, which was significantly higher than that of cobs from C1 and C2 plots (p < 0.01). The grain weight increased significantly by 23% in B1-supplemented plots (p < 0.01) and there were no differences between B2-supplemented, C1, and C2 plots. At the end of the treatment, the soil of the B1-supplemented plots exhibited increased levels of sulfate, nitrate, magnesium, conductivity, and saturation percentage. Based on these results, the economic sustainability of this application in agriculture was studied at a standard price of €190 per ton of biochar. Amortization of this investment can be achieved in 5.52 years according to this cost. Considering the fertilizer cost savings of 50% and the water cost savings of 25%, the amortization can be achieved in 4.15 years. If the price of biochar could be reduced through the CO2 emission market at €30 per ton of non-emitted CO2, the amortization can be achieved in 2.80 years. Biochar markedly improves corn production in the Mediterranean climate. However, the amortization time must be further reduced, and enhanced production must be guaranteed over the years with long term field trials so that the product is marketable or other high value-added crops must be identified.


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