Advanced Journal of Agricultural Research (AJAR) ISSN: 2367-9816, Vol. 8(5), pp. 244-256, December, 2021.  © Advanced Scholars Journals

Review paper

Micro-morphology of the rhizosphere with focus on plant nutrition: a review

Dr. AN Sarkar

 University College of North Wales (Now Bangor University), Bangor, Caerns, Wales, U.K.

Ex-Scientist (Soil Science), Indian Council of Agriculture Research (ICAR), New Delhi

University of Petroleum and Energy Studies (UPES), Dehradun, Uttarakhand, India.

(International  Business & Dean (Research), Asia-Pacific Institute of Management, New Delhi.                                         

E.mail: [email protected]

Accepted 22^nd May, 2021.

Abstract

The paper highlights the historic background of Rhizosphere investigations focusing on Root-Soil Interface activities in terms of micro-morphology, using advanced micro-morphological investigation techniques and tools such as high-resolution microscope, scanning electron microscope, electron-probe X-ray-analyser technique, X-Ray Diffraction Technique, Thin  Micro-Autoradiography using Kodak thin myler films onto thin sections with optical polish < 1.0 micron. The second part of the paper refers to a number of factorial pot experiments with French beans (Phaseolus vulgaris L) as test crop, involving three nitrogen sources (viz. ammonium phosphate, choline phosphate  and calcium chloride) at 2 N levels (500 ppm n and 1000 ppm N), 2 initial soil pH levels adjusted at pH 7 & pH 8 and two growth (G) stages (21 days and 42 days) were conducted under a standard growth chamber condition ( temperature 28⁰C_, light intensity 10, 000 LUX, R.H. 60%). Following dry ashing (475⁰C) shoots and roots were analysed for H₂PO₄^-2 (Phospho- molybdate method ( Jackson, 1964) Ca²⁺, Mg²+  , K+  ,Na+,  NH₄+ , NO₃^- , Cl­^­-), dithinate-citrate extractable Fe²+ ,  Mn²⁺ , Zn²⁺ ( Mehra and Jackson, 1960 ). The analytical values of soil (rhizosphere and non-rhizosphere) and root and shoot parameters were subject to Analysis of Variance Tests (ANOVA Test) to determine significant differences of based on single factors of factorial combinations and reveal ‘main effects’ and interactions. The summary of results of these experiments is briefly summarized in the relevant sections of the paper.

Key words: Micro-morphology, Rhizosphere, Soil-Root Interface, Plant Nutrition, Factorial Experiment