Study of variegated and white flower petals of Capparis spinosa expanded at dusk in arid landscapes

In this study, we provide the first evidence of two pairs of petals of the rapidly expanded and short-lived nocturnal flowers of Capparis spinosa L. （caper） during the prolonged drought period in Eastern Mediterranean region. The corolla of the winter-deciduous, perennial C. spinosa consists of two pairs of petals： a pair of white dis- tinct petals and a pair of connate variegated petals with green basal parts. The results indicated the presence of substantially different amounts of chlorophyll in the two pairs of petals, while their carbohydrates＇ content is com- parable with that of the green sepals. High resolution imaging of petal surfaces of short-lived flowers of C. spinosa, obtained by using scanning electron microscopy, revealed stomata on the adaxial epidermis on both the white and the green parts of the variegated petals; while dense hairs were found on the surface ofthe abaxial green parts of the variegated petals. Adaxial, epidermal cells of the variegated petals, viewed using atomic force microscopy, pos- sess a submicron, cuticular microfolding that differs between the white and the green parts of the petals. It appears that microridges on the adaxial, white parts of petals of C. spinosa compensate for an increase in cell surface area of the short lived petals, while the roughness of the green parts of petals was found to be higher than that of the white parts. Thus, the micromorphology of surfaces of epidermal cells is expected to affect optical properties and wettability of the floral tissues. These findings may be particularly important for understanding the performance of the short-lived petals of C. spinosa, which are exposed to dryland environments.

Aspects on the relief of living surfaces using atomic force microscopy allow“art”to imitate nature

The visualization of the surface of biological samples using an atomic force microscope reveals features of the external relief and can resolve very fine and detailed features of the surface.We examined specimens from the skin of the amphibians Salamandra salamandra Linnaeus,1758,Lyciasalamandra luschani basoglui Baran&Atatür,1980 and Mesotriton alpestris Laurenti,1768,and from the surface of pollen grains of the plant species Cyclamen graecum Link,1835 and Cistus salviifolius Linnaeus,1753,which exhibit certain interesting features,imaged at the nanoscale level.It is likely that the relief influences the attributes of the interfaces between the tissues and the environment.We found that the microsculpture increases in size the surface of the examined tissues and this might be particularly important for their performance in the field.Microsculpturing of amphibians’skin may affect water regulation,dehydration and rehydration,and cutaneous gas exchange.Pollen grain relief might affect the firmness of the contact between pollen surface and water droplets.High resolution imaging of the external relief showed that roughening might induce wetting and influence the water status of the specimens.In addition,roughness affects the radius of water droplets retained in between the projections of the external relief.Roughness of the tissues was highly correlated with their vertical distance,whereas surface distances were highly correlated with horizontal distances.By enabling a more detailed characterization of the external sculptures,through sophisticated techniques,a more comprehensive examination of the samples indicates similarities among different living tissues,originated from different kingdoms,which can be attributed to environmental conditions and physiological circumstances.