Tendril

Abstract: The helix hand reversal exhibited by the tendrils of climbing plants when attached to a support is investigated. Modeled as a thin elastic rod with intrinsic curvature, a linear and nonlinear stability analysis shows the problem to be a paradigm for curvature induced morphogenesis in which symmetry breaking is constrained by a global invariant.

Abstract: The compound leaf primordium of pea represents a marginal blastozone that initiates organ primordia, in an acropetal manner, from its growing distal region. The UNIFOLIATA (UNI) gene is important in marginal blastozone maintenance because loss or reduction of its function results in uni mutant leaves of reduced complexity. In this study, we show that UNI is expressed in the leaf blastozone over the period in which organ primordia are initiated and is downregulated at the time of leaf primordium determination. Prolonged UNI expression was associated with increased blastozone activity in the complex leaves of afila (af), cochleata (coch), and afila tendril-less (af tl) mutant plants. Our analysis suggests that UNI expression is negatively regulated by COCH in stipule primordia, by AF in proximal leaflet primordia, and by AF and TL in distal and terminal tendril primordia. We propose that the control of UNI expression by AF, TL, and COCH is important in the regulation of blastozone activity and pattern formation in the compound leaf primordium of the pea.

Abstract: The anatomy of vegetative structures of cultivated grapevines, as described in selected literature, is presented, with emphasis on development of established vines of Vitis vinifera . Other topics briefly considered are the anatomy of propagules, muscadine grapes, tetraploid vines, phylloxera galls, mineral-deficient vines, and injury of leaves by ozone and 2,4-D. The terms used to describe grapevine morphology and anatomy are defined in a glossary. A growing root shows zones of cell division, cell elongation, and tissue differentiation. Vascular structure is similar in the root and the stem, although the mitotic activity of vascular and cork cambia is more irregular. Root cortex is often invaded by endotrophic mycorrhiza. The stem primary vascular system is composed of leaf, bud, and tendril traces. Procambium and phloem differentiate acropetally, and xylem differentiates in both directions from the nodes. During the first growing season of the stem, a cambium produces secondary xylem and phloem and extends rays. Xylem consists of large scalariform vessels surrounded by thick-walled pitted parenchyma and large masses of living septate fibers. Phloem consists of blocks of living septate fibers alternating with blocks of sieve elements, companion cells, and parenchyma. Ray cells are pitted and thick-walled in the xylem but thin-walled in the phloem. Cells of the stem and root store starch, which is greatly depleted when shoots begin to grow in the spring. Phellogen forms from the living cells of the nonconducting primary phloem in the first year in stems of Euvitis Planch. (in the subepidermal layer in Muscadinia Planch.), and then successively each year in the nonconducting secondary phloem. It cuts off all the tissues lying outside of it, and these are shed with the periderm. In spring, sieve elements formed the previous year are revitalized and function as conduits until new sieve elements are formed from the cambium. Each foliage leaf on a growing shoot has a precocious axillary bud consisting of a single prophyll and a variable number of leaves. This develops into the summer lateral branch. The four vascular traces of this axillary bud diverge from the traces of the subjacent tendril or bud, not from those of the subtending leaf. The bud in the prophyll of the summer lateral develops into the primary bud with 2-3 prophylls, a few leaves, and then several leaves opposed by clusters or tendrils in a generally regular pattern. Formed in the axils of the two basal prophylls of the primary shoot are the secondary and tertiary buds, respectively. These three buds, surrounded by the prophyll of the summer lateral, enter dormancy at the end of the growing season and constitute the compound bud or eye of the mature cane. The next season the primary bud develops into the fruiting shoot. The secondary and tertiary buds may develop into shoots or remain latent for extended periods. A tendril arises as a primordium on the apical meristem opposite that of a leaf. Two of its vascular traces are connected with those of the bud below it, and two with those of the leaf above it. It functions first as a hydathode and later as a twining organ. At each node, five traces to the leaf leave the ring of stem vascular bundles through separate gaps. The traces divide and anastomose to form the complicated network of palmate venation in the leaf, each tooth ending in a hydathode. Blade tissues of a mature leaf, which are differentiated from six layers of meristematic cells, comprise the upper epidermis, one layer of palisade cells, three layers of spongy mesophyll cells, and the lower epidermis with stomates.

Abstract: Glucose, fructose, galactose, sucrose, maltose, melibiose, raffinose, and stachyose were identified in the leaves, bark, roots, and berries of Vitis vinifera L. var. Thompson Seedless. In addition to these sugars, verbascose and manninotriose were found in the leaves and bark. Malic, tartaric, citric, isocitric, ascorbic, cis -aconitic, oxalic, glycolic, glyoxylic, succinic, lactic, glutaric, fumaric, pyrrolidone carboxylic, α-ketoglutaric, pyruvic, oxaloacetic, galacturonic, glucuronic, shikimic, quinic, chlorogenic, and caffeic acids were identified in the leaves, bark, roots, and berries. Glucose, fructose, sucrose, malate, tartrate, and citrate were determined quantitatively in the leaf, petiole, xylem, bark, tendril, bud, puduncle pedicel, berry, lateral roots, and main roots at 4 separate physiological stages of growth. In addition, changes in the concentrations of fructose, glucose, malate, and tartrate in leaves were measured during a 36-day period starting from budburst.