Development and Structure of Drought-tolerant Leaves of the Mediterranean Shrub Capparis spinosa L.

Abstract

Capparis spinosa (caper), a winter-deciduous perennial shrub, is a consistent floristic element of Mediterranean ecosystems, growing from May to October, i.e. entirely during the prolonged summer drought. The internal architecture of young and fully expanded leaves was studied, along with certain physiological characteristics. Capparis spinosa possesses thick, amphistomatic and homobaric leaves with a multilayered mesophyll. The latter possesses an increased number of photosynthesizing cells per unit leaf surface, a large surface area of mesophyll cells facing intercellular spaces (Smes) and a low percentage of intercellular space per tissue volume. Smes and chlorophyll content attain their maximum values synchronously, slightly before full leaf expansion. Nitrogen investment is also completed before full leaf expansion. The structural features, in combination with the water status, could contribute to enhanced rates of transpiration and photosynthesis under field water shortage conditions.

Leaf expansion in Rhamnus alaternus L. by leaf morphological, anatomical and physiological analysis

“…Net photosynthesis increases from bud break to full leaf expansion and total chlorophyll content has the same trend (r = 0.97); peaking of total chlorophyll content with photosynthetic rates might underline that mesophyll cell expansion and chloroplast development simultaneously occur (Rhizopoulou and Psaras 2003). Moreover, the attainment of the maximum photosynthetic rates synchronously to S m , at full leaf expansion, underlines a ''normal'' greening process, according to Rhizopoulou and Psaras (2003).…”

“…In particular, the high S m (38.4 ± 1.0 m 2 m -2 ), which is the true CO 2 absorbing surface may be advantageous because it facilitates the internal CO 2 diffusion, and thus it justifies the R. alaternus higher photosynthetic rates than other Mediterranean species (Gratani and Ghia 2002;Gratani and Bonito 2009). Net photosynthesis increases from bud break to full leaf expansion and total chlorophyll content has the same trend (r = 0.97); peaking of total chlorophyll content with photosynthetic rates might underline that mesophyll cell expansion and chloroplast development simultaneously occur (Rhizopoulou and Psaras 2003). Moreover, the attainment of the maximum photosynthetic rates synchronously to S m , at full leaf expansion, underlines a ''normal'' greening process, according to Rhizopoulou and Psaras (2003).…”

“…However, anatomical leaf traits such as cell wall thickness, mesophyll cell size and volume of the intercellular spaces are related to physiological traits affecting the CO 2 diffusion along the pathway from the air to the carboxylation sites (Parkhurst 1994;Syvertsen et al 1995;Evans and Loreto 2000;Terashima et al 2001;Rhizopoulou and Psaras 2003).…”

Occurrence of homobaric and heterobaric leaves in two forest types of southern Brazil

“…The presence of BSEs can protect leaf lamina from hydric stress and increase light absorption and mechanical support (Terashima 1992;Karabourniotis 1998;Nikolopoulos et al 2002;Rhizopoulou & Psaras 2003). Yet in homobaric leaves, gas diffusion in the mesophyll can be more efficient due the absence of BSEs (Pieruschka et al 2006).…”

First report of caper (Capparis spinosa) serious infestation by Eurydema eckerleini in Cyclades Islands, Greece (Hemiptera: Heteroptera, Pentatomidae)

“…This is achieved by the extension of the root system downward to a depth of up to 20 m in order to reach subsoil water (Rhizopoulou & Kapolas 2015) and horizontally in order to maximize access to rainfall water (Sozzi 2001). This characteristic is supported by a high hydraulic conductivity achieved by highly specialized conducting tissue, both in roots and stems, along with the presence of thick, amphistomatous and highly photosynthetically efficient leaves (Rhizopoulou et al 1997;Sozzi 2001;Rhizopoulou & Psaras, 2003;Sakcali et al 2008;gan et al 2013).…”