Vascular System of the Stem of the Wheat Plant. I. Mature State

1972 ◽  
Vol 20 (1) ◽  
pp. 49 ◽  
Author(s):  
JW Patrick

The courses of the various vascular bundles in the nodes of the main tiller of Triticum aestivum L. have been reconstructed from anatomical observations of con- secutive serial transverse sections. Of the bundles entering a node (n) from its attached leaf, the first-formed and largest, the median, passes directly through the node to the second node below (n-2), where it bifurcates and fuses with other strands. These continue to node n- 3 before fusing completely with the nodal plexus. The next six bundles to form (laterals) establish some links with bundles from higher leaves in the node of entry, much more extensive connections in node n- 1, and fuse completely with the nodal plexus in node n-2. The next four lateral bundles to differentiate are more extensively linked in node n and fuse completely with the nodal plexus in node n - I . The remaining 16-20 bundles from the leaf (intermediates) follow much the same course but develop more extensive connections with other bundles. The extensive plexus which develops in each node ensures vascular connections between most bundles. The significance of these in transport is briefly discussed.

1972 ◽  
Vol 20 (1) ◽  
pp. 65 ◽  
Author(s):  
JW Patrick

The sequence of vascular differentiation in the shoot of the main tiller of Triticum aestivum L. was reconstructed from seriai transverse sections of shoot apices made at various stages of development. The pattern of initiation and development of the pro- cambial strands was confirmed. The provascular bundles of the pith plexus arose independently and developed acropetally from the base of the future node. Early dif- ferentiation of proto-phloem and -xylem in the main procambial strands proceeded bidirectionally up the leaf primordia and down the stem from a site of initiation isolated from other differentiated vascular elements. Further development was basipetal from the tip of the primordia, and the rate of differentiation of the sieve elements was sufficient to maintain phloem continuity across the intercalary meristems of the laminae, sheaths, and internodes. Within the developing nodes sieve tube differentiation in the cross-linking strands lagged behind that of the leaf traces they interconnected, and this may influence the movement of photoassimilate from a recently expanded leaf to the apex.


Biomics ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 329-336
Author(s):  
A.R. Lubyanova ◽  
F.M. Shakirova ◽  
M.V. Bezrukova

We studied the immunohistochemical localization of abscisic acid (ABA), wheat germ agglutinin (WGA) and dehydrins in the roots of wheat seedlings (Triticum aestivum L.) during 24-epibrassinolide-pretreatment (EB-pretreatment) and PEG-induced dehydration. It was found coimmunolocalization of ABA, WGA and dehydrins in the cells of central cylinder of basal part untreated and EB-pretreated roots of wheat seedlings under normal conditions and under osmotic stress. Such mutual localization ABA and protective proteins, WGA and dehydrins, indicates the possible effect of their distribution in the tissues of EB-pretreated wheat roots during dehydration on the apoplastic barrier functioning, which apparently contributes to decrease the water loss under dehydration. Perhaps, the significant localization of ABA and wheat lectin in the metaxylem region enhances EB-induced transport of ABA and WGA from roots to shoots under stress. It can be assumed that brassinosteroids can serve as intermediates in the realization of the protective effect of WGA and wheat dehydrins during water deficit.


Author(s):  
Shailja Dubey ◽  
Renu Bist ◽  
Shrilekha Misra

Objective: Ethyl methano sulphonate (Ems), a chemical mutagen is widely used to induce a large number of functional variation in wheat plant. The objective of present study was to determine the activity of enzymatic antioxidants and Lipid peroxidation (LPO) after EMS exposure in a wheat plant in M1, M2 and M3 generation of Triticum aestivum L. var. HD 2894.Methods: Presoaked seeds were treated with EMS for 6 hour with different concentration like 0%, 0.1%, 0.2%, 0.3%, 0.4% and 0.5%. Some biochemical parameter such as Catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR) and Lipid peroxidation (LPO) were studied.Results: Our result showed that EMS affects enzymatic and oxidative parameters in all generation. CAT, GR, APX and LPO activity was found to be reduced in m1 generation as compared to control. A simultaneous elevation was recorded in the concentration of ems compared to control treated plants after given the exposure of ems in m2 and m3 generation. Data analysis of antioxidant and LPO during the m2 generation showed that the effect of the mutagen on the activity of antioxidant and LPO did not cease in the m1 but continued to affect the m2 generation. Analysis of m3 generation showed stability in the activity of antioxidant and LPO from m2 to m3 generation.Conclusion: Lethal dose of ems was determined by the activity of antioxidant under laboratory condition. In this experiment, quantitative determination was applied as a regular procedure. The data analysis showed the activity of antioxidant, LPO and doses of ems concentration in m1, m2 and m3 generation. Variability observed on the basis of mean and standard deviation. On the whole, differences between concentrations and treatment time of Ems significantly affect the activity of antioxidant and LPO in all generation. 


2019 ◽  
pp. 291-297
Author(s):  
Marei Abdelkarim

Rhizospheres of crop plants are complexes of chemical and microbial interactions. Of importance, arbuscular mycorrhizal fungi (AMF) are beneficial microorgansims associated with roughly eighty-percent of terrestrial land plants. In this mutualistic symbiosis, the fungus receives the photosynthetic product (sugar) fixed from its host by photosynthesis. In return, the host plant gains a plethora of benefits from the fungus such as enhanced nutrient uptakes, protection against both biotic (soil-borne root pathogens, insect attack) and abiotic (drought, heavy metal pollution, and soil salinity) stresses. Taxonomically, AMF belong to a new erected phylum called Glomeromycota. The field study was conducted in a farm owned and supervised by The Great Man-Made Project in February 2019. The present study was performed to determine the presence or the absence of AMF in a field cultivated with wheat crops (Triticum aestivum, L.) during the vegetative stage, and also to investigate soil physiochemical properties effect on AMF colonization. Results showed that colonization of wheat plant roots were significantly low. The result clearly implies that high-input fertilizers viz., phosphorus fertilization, and agricultural practices such as intensive tillage drastically reduced AMF colonization.


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