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In the current investigation an attempt has been made to document the floristic diversity, chorotype analysis and occurrence of the Pteridophytes of Pakistan. Previously published literature was consulted in order to confirm the nomenclature, precise locations and other attributes of this unique group of plants. Many field trips were undertaken in various districts of Khyber Pakhtunkhwa and specimens of various herbaria were studied in Pakistan and from other countries. Our updated list of taxa confirms that there are 168 taxa belong to 45 genera and 19 families. Pteridaceace and Dryopteridaceae are found to be largest families with 35 taxa each (41.67%), followed by Aspleniaceae with 28 taxa (16.67%) and Athyriaceae with 24 taxa (14.28%). Asplenium is the largest genus with 28 taxa (16.67%), followed by Dryopteris with 17 taxa (10.12%) and Polystichum with 15 taxa (8.93%). Phytogeographically the Sino-Himalayan elements is the major component of the diversity of the pteridophye flora with 94 taxa (55.95%), 18 taxa (10.71%) are cosmopolitan and European elements have 13 taxa (7.74%). We found that 43 taxa (25.6%) are extremely rare, 39 taxa (23.21%) are infrequent and 37 taxa (22.02%) are common. [ABSTRACT FROM AUTHOR]

The present study was aimed at high level and cost-effective production of phytase by Aspergillus niger under solid state fermentation adopting the response surface optimization method. Plackett-Burman design (PBD) and Central composite design (CCD) of Response surface methodology (RSM) were employed for screening and optimization of cultural conditions for maximum phytase production. Among 8 factors, incubation temperature, initial pH, incubation period, NH4NO3 and tween-40 were identified as significant factors by Plackett-Burman design (PBD) due to their positive effect on phytase production. Then, the optimization of these significant factors was conducted by Central Composite design (CCD), and incubation period (6 days), incubation temperature (35°C), initial pH (6), NH4NO3 (0.75%) and tween-40 (0.6%) were found to be optimum levels for best enzyme production. After statistical optimization, maximum amount of phytase production was obtained i.e. 406.45 IU/g, as it was 297.25 IU/g using conventional one factor at a time (OFAT) optimization approach. There was 1.37-fold increase in phytase yield using response surface methodology (RSM). These results indicated the efficacy of the response surface methodology to enhance phytase production by Aspergillus niger using solid state fermentation process. [ABSTRACT FROM AUTHOR]