Microalgae are a group of photosynthetic microorganisms living in the water. They are in the spotlight as biostimulators and biofertilizers in modern renewable and sustainable agriculture system, attributed to characteristics such as photosynthetic, and metabolism of various industrial wastes and to increase production when treating crops. Scenedesmus sp. CHK0059 is also one of the microalgae with these characteristics, and it has been reported to suppress various diseases in crops and promote the health of vegetables. However, the mode of action that has a positive effect on plants is not yet well understood. This study was designed to focus on the modulation in diversity change of plant microbiota community, which was the result of the preliminary study, and to determine the direct changes in microbial members that trigger the diversity change in the Arabidopsis model system. As a result, there was no change in the phenotype of Arabidopsis and the microbiota community structure in the rhizosphere during the treatment period, but two bacteria genera, Brevibacterium and Pseudomonas, dominance in the rhizosphere was positively correlated with the CHK0059 treatments. And the bacteria had a positive network correlative relationship with 24 other bacteria. Our findings suggest that the application of microalgae was correlated with several microbiota members in the rhizosphere and was expected to affect the microbiota community structure modification in long-term treatment.

An experiment was carried out at the Field Laboratory of the Department of Crop Botany, Bangladesh Agricultural University, Mymensingh from March to July, 2001 to investigate the effect of biofertilizers on morpho-physiological characters of okra. The experiment was laid out in a randomized complete block design with four replications. There were nine treatments such as ~textrmT0 (control), ~textrmT1 (Azotobacter biofertilizer), ~textrmT2 (Azospirillum biofertilizer), ~textrmT3 (Azotobacter+Azospirillum biofertilizers), ~textrmT4 (Azotobacter+Cowdung 5 ton ~textrmha-1 ), ~textrmT5 (Azospirillum+Cowdung 5 ton ~textrmha-1 ), ~textrmT6 (Azotobacter+Azospirillum+Cowdung 5 ton ~textrmha-1 ), ~textrmT7 (Cowdung 5 ton ~textrmha-1 ) and ~textrmT8 (60% Nitrogen). The experimental results revealed that significant variations exist among the treatments regarding morphological characters e.g. plant height, number of leaves/plant, stem base diameter, tap root length, and physiological characters like, root dry weight, leaf area index and crop growth rate. Number of leaves/plant, stem base diameter, root length, root dry weight, leaf area index and crop growth rate were found higher in ~textrmT4 , ~textrmT5 , ~textrmT6 and ~textrmT8 than the others. In all the parameters, ~textrmT8 gave the similar result with biofertilizers in combination with cowdung treatments and ~textrmT7 showed identical with ~textrmT0 (control). Biofertilizer treatments had insignificant effect on 1000-seed weight(g). Experimental results mentioned above revealed that morpho-physioligical characters of okra could be modified by the application of biofertilizer+cowdung. However, biofertilizers+Cowdung treatments were comparable to ~textrmT8 (60% Nitrogen) in this study. This suggests that ~textrmT4 or ~textrmT6 or ~textrmT5 were more benificial in environmentally friendly okra cultivation and may be used as an alternative of inorganic nitrogen by saving cost of production and sustaining productivity.