The distribution of solutes in the various cells of sugar beet (Beta vulgaris L.) source leaves, petioles, and sink leaves was studied in tissue prepared by freeze-substitution. The differences in degree of cryoprotection indicated that sieve elements and companion cells of the source leaf, petiole, and sink leaf contain a high concentration of solute. The osmotic pressure of various types of c...

Plants differ in tissue localization of nitrate reduction and assimilation. Some species reduce nitrate primarily in the leaves, whereas other species localize nitrate reduction and assimilation in the roots. We determined how nitrate assimilation is partitioned among leaves, stems and roots of poplar (Populus tremula L. x P. alba L.) by comparing tissue differences in in vivo nitrate reductase...

In vivo and in vitro sublethal exposure of abrin, glycyrrhizin (active component of Abrus precatorius seed and root), sanguinarine, protopine (Argemone mexicana seed) and oleandrin (Nerium indicum leaf) inhibited the acetylcholinesterase, lactic dehydrogenase, acid and alkaline phosphatase activity in the nervous tissue of Lymnaea acuminata. The succinic dehydrogenase activity in the nervous ti...

The relationship of leaf and fruit transpiration rates with the incidence of spongy tissue in mango cultivars Dashahari (free from spongy tissue) and Alphonso (susceptible to spongy tissue) was investigated. Leaf transpiration rates were similar in both the cultivars, however the fruit transpiration rates were significantly higher in cv. Dashahari. Artificially induced variations in fruit trans...

The effect of chilling on photosystem II (PSII) efficiency was studied in the variegated leaves of Calathea makoyana, in order to gain insight into the causes of chilling-induced photoinhibition. Additionally, a relationship was revealed between (chilling) stress and variation in photosynthesis. Chilling treatments (5 degrees C and 10 degrees C) were performed for different durations (1-7 d) un...

A mathematical model is presented to simulate the growth of a plant leaf. The tissue in the leaf has been regarded as a viscous, incompressible fluid whose 2D expansion comes from the non-zero specific growth rate in area. The resulting system of equations are composed of the modified Navier-Stokes equations. The level set method is used to capture the expanding leaf front. Numerical simulation...

A mathematical model is presented to simulate the growth of a plant leaf. The tissue in the leaf has been regarded as a viscous, incompressible fluid whose 2D expansion comes from the non-zero specific growth rate in area. The resulting system of equations are composed of the modified Navier-Stokes equations. The level set method is used to capture the expanding leaf front. Numerical simulation...

Aloe barbadensis (aloe-vera) also famous as a first aid plant is a valuable natural medicine. Its leaves have parallel venation that contains a soothing thick gel inside it and is useful for treatment and curing of wounds and diseases. In this paper, investigations were carried out to study the effect of dc and ac resistances of the aloe barbadensis leaves. The resistance of the leaf measured s...

The genus Cyperus with five subgenus and 29 species, is the second largest genus of Cyperaceae family in flora of Iran. In this research, stem and leaf anatomy of 10 species belonging to subgenus Cyperus is investigated. The stems in transverse section of all examined species were triangular except for C. bulbosus which was subterete to polygonal. The ground tissue was spongy with numerous and ...

Leaf senescence is a programmed event where resources are mobilised from older tissues to the meristematic regions of the plant. In white clover (Trifolium repens L.), leaf and stolon senescence have an important impact on the persistence of the legume in pasture. As part of our investigation of leaf senescence, we have evidence for a central role for the plant hormone ethylene and have identif...