(n.) The young tissue of a fibrovascular bundle before its component cells have begun to be differentiated.
Example Sentences:
(1) Light and electron microscopical studies showed that, during preculture, procambium cells of embryos became highly susceptible to Agrobacterium infection.
(2) Lateral and intermediate veins are initiated in this central layer, most often by divisions which contribute daughter cells to both the procambium and the ground meristem.
Xylem
Definition:
(n.) That portion of a fibrovascular bundle which has developed, or will develop, into wood cells; -- distinguished from phloem.
Example Sentences:
(1) As shown earlier, at zero turgor pressure the intracellular freezing point of the parenchyma cells matches closely the negative pressure in the xylem sap.
(2) UDP-glucose was found to be the most important sugar nucleotide isolated from both cambial and young xylem tissue.
(3) The abnormal proliferation of lateral buds in the former plants is probably linked to the elevation of cytokinin level in xylem sap caused by strain IC3342.
(4) Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots of Tagetes lucida, T. filifolia, Elytraria imbricata, and Holodiscus dumosus, and from root xylem of Ceanothus depressus and Phaseolus ritensis.
(5) A cDNA clone (Ptomt 1) encoding a lignin-bispecific O-methyltransferase (OMT) was isolated by immunological screening of a lambda gt11 expression library prepared from mRNA of developing secondary xylem of aspen (Populus tremuloides).
(6) Virus particles were present in all cell types of the epidermis, mesophyll, phloem, and xylem.
(7) Ultrastructural examination of leaf tissue of Nicotiana benthamiana infected with Indian cassava mosaic virus (ICMV) revealed abnormalities in phloem and, occasionally, xylem cells.
(8) This protein is stored in xylem ray cells during the winter season and is degraded in late spring.
(9) When cells were grown in medium with only 2,4-dichlorophenoxyacetic acid for a period of 5--10 subcultures and samples were transferred to the induction medium at intervals during the subcultures, the amounts of phenylalanine ammonia-lyase activity and the number of xylem elements induced progressively declined.
(10) A photo-oxidized solution of 3,3'-diaminobenzidine (DAB) is used to stain xylem parenchyma mitochondria in specimens prepared from lupin hypocotyls fixed with glutaraldehyde and osmium tetroxide and embedded in Epon.
(11) Likewise, the PRPs are localized in xylem vessel elements and fibers in tomato, petunia, potato and tobacco stems.
(12) This agrees with the present data, that the fluid which exudes from the xylem by applying gas pressure on the leaves is practically pure water; freezing point is rarely above 0.01 to 0.02 degrees .
(13) Occasionally BNYVV antigen was detected predominantly, but not exclusively in the xylem vessels.
(14) The xylem in the body of the haustorium of E. bidwillii has the shape of an inverted conical flask with the expanded portion being known as the vascular core.
(15) Other explanations are discussed, including a possible particularity of the infection in xylem tissue or a specific property of an unusual CaMV isolate.
(16) The bark, xylem of stem, and root of (1) Bombax malabarica DC.
(17) A biphasic pattern of gene expression and enzyme activity for OMT was observed from xylem samples of aspen during the growing season which suggests linkage between gene expression for a monolignol biosynthetic enzyme and seasonal regulation of xylem differentiation in woody plants.
(18) The former possesses the xylem fibres and tracheids with steep, tertiary spiral thickenings, while the latter possesses sclereids at stem-nodes.
(19) The bean phenylalanine ammonia-lyase gene 2 (PAL2) is expressed in the early stages of vascular development at the inception of xylem differentiation, associated with the synthesis of lignin precursors.
(20) In plant pathogenesis, less specific mechanisms of pathogenesis occur: exopolysaccharides cause wilting by blocking xylem vessels, are partly responsible for water-soaked lesions, and may also aid in invasion, growth, and survival in plant tissues.