Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Xylem Vessel Variability at Three Positions of Rice Root (oryza Sativa L)

M.K. Bashar
Bangladesh Rice Research Institute, Gazipur 1701

Abstract/ Executive Summary:

Root xylem vessel numbers and areas at different positions of the roots of one African upland rice variety, Moroberekan and one semidwarf modern . lowland variety, IR20 were• studied. The plants were grown in hydroponic cultur in a phytotron glasshouse under controlled conditions. Samples were taken from the base, middle and tip of roots from randomly selected plants. Within a root, the lowland variety produced both a higher number as well as a larger area of xylem vessels at the base; the xylem vessel number and area gradually decressed at the middle and tip of the root. This trend was not observed in the upland variety. There were no significant differences among the plants and roots within plants in Moroberekan in respect of xylem vessel number or area. However, the IR20 plants showed significant differences in root xylem vessel number. The smallest contribution to the total variation was due to root while the greatest contribution in cases of both the characters and both the varieties came from the sampling position within root. Thus, sampling should be from a certain section of the root, preferably from the tip.

Keywords: Variability, Xylem vessel, Rice root

Location: Phytotron of the International Rice Research Institute

Start Date:

End Date:

Program Area: Crop-Soil-Water Management

Commodity: Rice

Objectives:

To: i) observe the variations among plants and roots; ii) determine the changes in xylem vessel number and area due to sampling position within a root; and iii) estimate the contribution of each variable to the total variation.

Methodology:

The experiment was conducted in the phytotron of the International Rice Research Institute. Moroberekan, an African upland rice variety and IR20, a semidwarf lowland variety, were used as the test materials, The varieties were grown in hydroponic culture under controlled conditions. Seeds of the test materials were surface sterllized for one minute with 0.1% mercuric chloride and germinated in' petridishes. After 3 d, the germinated seedlings were transferred to nylon seive trays placed in plastic trays 50%-concentration culture solution to cover the germination seeds. One 11 d old seedling was transferred into a styrofoam plant holder and placed in a PVC tube 7.5 cm in diameter and 50 cm in height. For the first week of seedling growth, 50%- concentration of culture solution was used; the full-concentration solution was used during the second and third weeks. In the fourth week, the N content of the culture solution was increased from 40 ppm to 80 ppm. The pH of the solution in the PVC tube was checked every day and was maintained between 5.0 to 6.0. Culture solution was added to the PVC tube as and when necessary to compensate for transpirational losses. The flow chart of the experimental procedure is shown in Fig.2. Five plants of each variety were taken at random, and three roots were randomly selected from each plant. The root samples were taken from the base, middle and tip portions 45 days after sowing (DS). Root cross sections for studying anatomical features were prepared with the help of a microtome (Johansen, 1940). The xylem vessel numbers in the three roots were counted and the xylem vessel diameters were measured under an ocular microscope at a 200 x magnification. Xylem vessel areas were computed from these data. Statistical analyses of the data were performed following the random model of tested design.

Source of Information: Bangladesh Rice J. 1(1) : 64-72 (1990)

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

The analysis showed that the least or no variation was due to root. Thus, any type of root may be sampled. Katayama (1966) reported the ratio of the diameter of the central cylinder to that of the cortex to be relatively constant in seminal, adventitious and lateral roots. The sampling of seminal roots is impractical for a large number of samples at 45 OS. The range of variation observed for both the characters and varieties due to plants was 0-24.3%. The lowland variety showed a greater variation than did the upland variety. The plant variations can be minimized by increasing the population size. The highest variation was observed for both the characters and the varieties due to position within root. The upland variety exhibited greater variation due to position of sample than did the lowland variety in respect of both root xylem vessel number and area. Thus, sampling should from a certain position of the root, preferable from the tip which can be sectioned even by free hand. There is a chance of loss of xylem vessels due to adaptive changes in the root in response to environmental chances, Sampling from the middle or base of the root may thus be misleading. Further studies with larger population sizes are needed to confirm these results.

Knowledge Management: Journal