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

新疆果树原胶的出胶调查/Investigation on Gum Output of Fruit Trees in Xinjiang[J]

以新疆果树为试材,研究了山桃、蟠桃、桃杏、杏、巴旦杏、李子、李子幼林、水蜜桃、黄果山楂、新疆梨、石榴共11个果树原胶的出胶率和出胶量.结果表明:山桃、蟠桃、巴旦杏、桃杏和杏的出胶率和出胶量较大,高达90％的树木都出胶,且单株出胶量多在40～50 g；李子和水蜜桃的出胶率则较小,一般在25％,单株出胶量1～3 g；黄果山楂、新疆梨和石榴未发现出胶

塔里木盆地塔里木沙拐枣群落特征/The community characteristics of Calligonum roborowskii A.Los in Tarim Basin[J]

塔里木沙拐枣(Calligonum roborowskii)主产塔里木盆地,是该地区主要防风固沙先锋树种.以塔里木盆地5个天然塔里木沙拐枣群落为研究对象,通过样方凋查,对物种组成,区系成分,群落结构,物种丰富度和多样性等要素进行了初步研究,结果表明:塔里木沙拐枣天然群落共出现种子植物11种,分属6科10属；该群落植物种类组成贫乏,区系成分简单.从属的地理成分分析来看,古地中海成分明显多于温带成分；群落生活型以高位芽植物占优势,1年生植物次之；群落的垂直结构简单,可分为灌木层、草本层；从多样性指数的数量特征来看,Shannon-Wiener多样性指数的变化范围为0.808-1.175,Simpson多样性指数的变化范围为0.489-0.641