background & aim: investigation of suspension cell culture and callus production in catharanthus roseus. catharanthus roseus is an herbaceous perennial plant belongs to the family apocynaceae. c. roseus is important as commercial medicinal plant because of its alkaloidal content. whole plant contains about 130 alkaloids those are classified as vinca alkaloids. vincristine and vinblastine; t...

In the identification process of weed materials available in "IRAN" herbarium, a specimen belonging to the genus Lactuca (Asteraceae) had the following characteristics: Plant annual, many stemmed from base; stem erect-slightly procumbent, slender, glabrous, whitish and leafy. Basal leaves dried; stem leaves ca. 7 × 0.5 cm, glabrous, linear-lanceolate, entire at margin, sessile, auriculate, auri...

Intracanopy plasticity in tree leaf form is a major determinant of whole-plant function and potentially of forest understory ecology. However, there exists little systematic information for the full extent of intracanopy plasticity, whether it is linked with height and exposure, or its variation across species. For arboretum-grown trees of six temperate deciduous species averaging 13-18 m in he...

The vascular tissues of plants are organized as strands of aligned cells in all the main organs. They differentiate from narrow, interconnected provascular cells, which are visible in the early leaf primordia of Arabidopsis thaliana in the top left panel. Plant hormones in the auxin class can induce the formation of additional vascular strands. Because auxins are produced in young leaves and th...

Prunus ferganensis (Kost. & Riab) Kov. & Kost, is closely related to cultivated peach, P. persica (L.) Batsch, but is distinguished by very long, unbranched leaf veins which turn and run parallel to the leaf margin at the edge of the leaf. Also, the pits have longitudinal grooves. Otherwise the tree and fruit of this species (or sub-species) resemble those of our familiar commercial peach. P. f...

The “Baja BC hypothesis”, which postulates that western Washington State, British Columbia and southern Alaska originated at the latitude ofMexico, has pitted paleomagnetic results against long-held interpretations about the tectonic evolution of western North America. In this paper we develop a new paleobotanical method for estimating paleolatitude and apply it to this problem. We start by sho...

Shoots are characterized by indeterminate growth resulting from divisions of undifferentiated cells in the central region of the shoot apical meristem. These cells give rise to peripheral derivatives from which lateral organ initials are recruited. During initial stages of cell recruitment, the three-dimensional form of lateral organs is specified. Lateral organs such as leaves develop and diff...