ABSTRACT
The status of colonization of Arbuscular Mycorrhizal Fungi [AMF] in the roots and AMF spore population in the rhizosphere soils of Turmeric [Curcuma domestica Vahl.] were assessed with the samples collected from Dashmail, Kantaji and Ramsagar of Dinajpur district; Thengamara of Bogra district and Boalmari of Faridpur district. Roots were assessed for AMF colonization after staining in aniline blue and rhizosphere soil samples were assessed for AM fungal spore population following wet sieving and decanting methods. Turmeric roots collected from different locations were found mycotrophic and the rhizosphere soil samples contained a large number of AMF spores. Significant variation of biodiversity of colonization and spore population were recorded in the present investigation. The range of AM colonization varied from 34% to 52% with the highest AM colonization was recorded from Kantaji [52%] and the lowest from Thengamara [34%]. The range of mycelial, vesicular and arbuscular colonization was recorded as 34-52%, 24-48% and 26-40% respectively. Poor, moderate and abundant intensity was recorded as 51-71%, 21-40% and 5-22% for mycelial colonization; 34-67%, 21-54% and 4-24% for vesicular colonization and 54-81%, 17-39% and 2-22% for arbuscular colonization respectively. Total range of spore population was recorded as 54-154 with the highest from Boalmari [154] and the lowest from Dashmail [54]. No correlation was found between percent colonization and the spore population. Glomus was dominant among the available AM fungal genera. Biodiversity of structural colonization in the roots and AM fungal genera in the rhizosphere soil samples of turmeric growing areas indicate the applicability of AM fungal technology in turmeric growing areas
Subject(s)
Mycorrhizae , Fungi , Curcuma , Zingiberaceae , Plant RootsABSTRACT
New pentadentate Schiff base ligand of S,S-dimethyldithiocarbazate was prepared after condensing with 2,6-diacetyl Pyridine and its Ni[II], Cu[II], Zn[II] complexes were obtained while reacted with corresponding metal salts. The ligand and its metal complexes were screened for antimicrobial activity against plant microbes' viz. Aspergillus sp., Fusarium solani, Penicillium sp., Verticillum sp. and Rhizobium sp. Observed action was good to moderate against Aspergillus sp., F. solani, Penicillium sp. and Verticillum sp. while for Rhizobium sp. it was negative or minute. Metal chelation increased the inhibitory competence of the ligand in most of the cases
ABSTRACT
Neem is one of the most valuable multi-purpose tree. This tree is very important culturally, medicinally and pesticidally and has gained worldwide recognition for its pharmaceutical and pesticidal properties. Our knowledge about the diseases of Neem is quite insufficient and fragmentary. Only leaf spots caused by Cercospora subsessilis are recorded from Bangladesh. The present work was undertaken to record the occurrence of powdery mildew on Neem leaves that has not been recorded earlier from Bangladesh. The symptoms of the disease were observed thoroughly under field conditions and the infected samples were brought to the laboratory for the detection of the causal organism from the diseased leaves. The causal organism of powdery mildew disease of Neem was observed in the laboratory and was identified as Oidium azadirachtae sp. nov. Initial infection in the leaf surface was found as a tiny powder mass and with the progress of the disease the whole area of the leaf was covered with a powder mass. The infection was also found on the lower surface of the mature leaves. The leaf becomes susceptible to infection when it is half the normal size and remains so till senescence. The disease was more prevalent in mature or old leaves than the young leaves. Because of leaf surface coverage with the powdery mass the photosynthetic activities are reduced and severe fungal attack results in defoliation. The spread of the diseases is favoured by high humidity, low temperature and mist. The specimens with typical powdery mildew symptoms were preserved in the laboratory