SYRVE FOR MYCORRHIZAL ASSOCIATION AND OCCURRENCE OF ENDOGONACEOUS SPORES IN SOILS OF SOUTHREN REGION OF PAKISTAN (MULTAN-BAHAWALPUR DIVISIONS AND SIND PROVINCE).

Abstract

A survey of Southren Region of Pakistan (MultanBahawalpur Divisions and Sind Province) was made for the occurrence of endotronhic mycorrhizae. One hundred and ninty one plants belonging to fourty seven families were collected from this region. The collected root samples were subjected to examine f or t he type of funcral symbiont and the extent of vesicular-arbuscular infection. r.nd000nc spores and sporocarps were identified which commonlv form mycorrhiza. Ninty two percent of the collected nlants snecies belonging to fourty four families were observed to be mycorrhizal. Some members of most families that were not infected in other ways, have been found infected with aseptate f ungi in this survey. Plant families such as Amaranthaceae, Chenopodiaceae, Cruciferae, Euphorbiaceae, Oxalidaceae, Polygonaceae and Rannunculaceae , so far considered to be non-mycorrhizal were seen to harbour mycorrhizal infection in most of their members. Plants belonging to families Cyperaceae, Nyctaginaceae,Nymohaeceae and Rosaceae, were observed to be non-mycorrhizal. ~oot infection in plants from Multan and B~hRwRlnur Divisions was subjected to infection rate statistical analysis. The infection ranaed 50-100 percent in sixty two percent of the infected plants examined and rest OC the thirty eiqht percent olants showed the infection ran~in0 between 2-49 percent. Similarly, the collections fro~ sinn Province when analysed for mycorrhizal infection showed 2 the presence of 50-100 percent infection rate i n fourtv seven percent of the examined plant roots and 0-45 percent infection rate in the remaininq fifty three oercent plant roots. A successful isolation of several strains or Phycomycetous funqi from a number of species Of plant soils was investiqated. Generally four types of Fndoqonaceous isolates were identified in the soils of this area. The following spores forms were recognized, (i) Glomus moss ae (Chalamydosnores light yellow brown, spherical to pear shaped, vacuolate), (ii) Glo~us macrocarpus var. ~acrocarpus (Ren brown, spherical, subtendinq hyphae shor.t), (iii) Acaulospora laevis ( resting spores borne laterctllv on a hyphae ter~inating in a vesicle), and (iv) GiqasDora calosnora ( Spores white or yellow, spherical, reticulate, subtending hyphae bulbous). In the soil samnles eXn~ined, the spore population of Glomus mosseae was in abundance compared with the other three types of spor.es, and that of Acaulospora laevis were least present. T rl) rcorrh', 11 • f t (,; .~r=tct(>r::"z"'d b' -rb'--ls~ules V. "1.) r (~ r1 1 d t ..c n. (J TrV E rc r oc n ~d, E, ( .. ) V st.a 1:'1< d anc. broad forming H-shaped confiquration, (ii) with narrow hyphae, occassionlv septate, light stained showing anaular nrojections , und(iii) brown septate or non-septate, with or without anqular. nrojections. . ) A close relationshio between intensity of infection and the stage of plant growth was observed. The venetativ', state of qrowth was in correlation with the heavy develoPm2r t. of arbuscules in the infected cells. Similarly, in flowerir.q and seed bearing stage of nlant growth, vesicular type or infection ( late mycorrhizal infection) was seen extensively. The rhizosphere at flowering or seed bearing stage encountred h i gh Endogonaceo us spore population as comnared to the ?lants in t heir vegetative phase of growth.