Comparison of five Calligonum species in Tarim Basin based on morphological and molecular data

Five Calligonum species endemic to the Tarim Basin – C. roborowskii, C. kuerlese, C. juoqiangense, C. yengisaricum, and C. taklimakanense – were compared using 14 morphological characteristics and nrDNA ITS and cpDNA trnL-F molecular data. Intraspecific and interspecific morphological variation was uncovered, with variation between species significant for most characteristics. Based on Euclidean distances, C. roborowskii and C. kuerlese were the most similar, and C. yengisaricum and C. kuerlese were the most divergent. There was very little variation in the molecular sequence data: although several variable sites were present in ITS and trnL-F regions, none of them were parsimony informative. Results of morphological and molecular analyses suggest that the various morphological characteristics of the studied Calligonum species are strongly shaped by environmental factors, with the observed intraspecific and interspecific morphological variation a product of the spatial isolation and extreme drought of the Tarim Basin

Spatio-seasonal variation of water quality influenced by land use and land cover in Lake Muhazi.

peer reviewedUnderstanding the influence of land use/land cover (LULC) on water quality is pertinent to sustainable water management. This study aimed at assessing the spatio-seasonal variation of water quality in relation to land use types in Lake Muhazi, Rwanda. The National Sanitation Foundation Water Quality Index (NSF-WQI) was used to evaluate the anthropogenically-induced water quality changes. In addition to Principal Components Analysis (PCA), a Cluster Analysis (CA) was applied on 12-clustered sampling sites and the obtained NSF-WQI. Lastly, the Partial Least Squares Path Modelling (PLS-PM) was used to estimate the nexus between LULC, water quality parameters, and the obtained NSF-WQI. The results revealed a poor water quality status at the Mugorore and Butimba sites in the rainy season, then at Mugorore and Bwimiyange sites in the dry season. Furthermore, PCA displayed a sample dispersion based on seasonality while NSF-WQI's CA hierarchy grouped the samples corresponding to LULC types. Finally, the PLS-PM returned a strong positive correlation (+ 0.831) between LULCs and water quality parameters in the rainy season but a negative correlation coefficient (- 0.542) in the dry season, with great influences of cropland on the water quality parameters. Overall, this study concludes that the lake is seasonally influenced by anthropogenic activities, suggesting sustainable land-use management decisions, such as the establishment and safeguarding protection belts in the lake vicinity

Chromosome numbers of three Calligonum species (Polygonaceae)

The chromosome number 2n=36 for Calligonum korlaense Z. M. Mao and the chromosome number 2n=18 for Calligonum yengisaricum Z. M. Mao and Calligonum ruoqiangense Liou f. is reported for the first time

Calligonum taklimakanense sp. nov. (Polygonaceae) from Xinjiang, China

Calligonum taklimakanense B. R. Pan & G. M. Shen, a new species of Polygonaceae from Taklimakan Desert, Xinjiang, China, is described and illustrated. It is closely related to C. ebinuricum Ivanova ex Soskov in having similar fruit shape and achenes with two rows of bristles, but differs in straight old branches and slightly coiled achenes without a long beak. Calligonum ebinuricum has tortuous old branches, very coiled achenes, and a 2-4 mm long beak