Surface runoff and phosphorus (P) loss from bamboo (Phyllostachys pubescens) forest ecosystem in southeast China

The effect of different fertilization treatments on runoff and nutrient losses under field conditions was investigated through setting runoff plots in bamboo (Phyllostachys pubescens) forests in a catchment of Taihu Lake. The results showed that, the runoff loss reached 356, 361 and 342 m3/hm2, while the soil particle loss reached 393, 392 and 442 kg/hm2, respectively, in the period from June 2009 to May 2010, under the treatments of control (CK), site-specific nutrient management (SSNM) and farmers’ fertilizer practice (FFP). The runoff and soil particle losses were highly correlated with the precipitation during the period. The largest phosphorus losses happened in August, when it had the largest rainfall of that year. The total phosphorus (TP) concentration of the 95% of the observed runoff samples exceeded 0.10 mg/l. The average bioavailable phosphorus (BAP) concentration of the runoff was 0.23 mg/l and the various phosphorus forms lost was strongly inter-correlated. Compared with FFP, the SSNM treatment reduced total P (TP) by 5%, total dissolved phosphorus (DP) loss by 15% and total bioavailable phosphorus (BAP) loss by 8%.Key words: Phyllostachys pubescens, ecosystem, surface runoff, phosphorus (P) loss

Cytological evidences of pollen abortion in Ornithogalum caudatum Ait

Ornithogalum caudatum Ait exhibits strong physiological adaptability; however, it suffers a serious menace of pollen abortion, as almost no seed is formed in the plants. In the current study, chromosome karyotype of root-tip cells (RTC) during mitosis, and chromosome behavior of pollen mother cells (PMC) during meiosis in O. caudatum were investigated. We recorded 18 euchromosomes with variable number (28~36) of B chromosomes in the somatic cells genome. In leptonema of meiotic prophase I, the synapsis between euchromosomes was normal, but there were several darker granular nodular bodies in the cells, which could be the precursor for B chromosomes. Some of the cells were observed as duplication loop in zygotene, indicating that the PMCs had gone through a chromosome structure variation with duplication, which could reduce the fertility of pollens. Numerous chromosome bridges, fragments and lagged chromosomes were observed in meiosis anaphase I. It reflects that these cells might have undergone paracentric inversion, which is one of the important reasons of pollen abortion. In meiosis anaphase II, the sister chromatids separate unusually forming the triad, which leads to gamete sterility. These findings conclude that pollen abortion in O. caudatum mainly results from the variation in chromosome structure, which could be related to the B chromosomes in somatic cells.Key words: Chromosome structure variation, B chromosome, root-tip cells, pollen mother cells, gamete sterility

Hemoglobin E syndromes in Pakistani population

<p>Abstract</p> <p>Background</p> <p>Hemoglobin E is an important hemoglobin variant with a worldwide distribution. A number of hemoglobinopathies have been reported from Pakistan. However a comprehensive description of hemoglobin E syndromes for the country was never made. This study aimed to describe various hemoglobin E disorders based on hematological parameters and chromatography. The sub-aim was to characterize hemoglobin E at molecular level.</p> <p>Methods</p> <p>This was a hospital based study conducted prospectively for a period of one year extending from January 1 to December 31, 2008. EDTA blood samples were analyzed for completed blood counts and hemoglobin variants through automated hematology analyzer and Bio-Rad beta thalassaemia short program respectively. Six samples were randomly selected to characterize HbE at molecular level through RFLP-PCR utilizing <it>Mnl</it>I restriction enzyme.</p> <p>Results</p> <p>During the study period, 11403 chromatograms were analyzed and Hb E was detected in 41 (or 0.36%) samples. Different hemoglobin E syndromes identified were HbEA (n = 20 or 49%), HbE/β-thalassemia (n = 14 or 34%), HbEE (n = 6 or 15%) and HbE/HbS (n = 1 or 2%). Compound heterozygosity for HbE and beta thalassaemia was found to be the most severely affected phenotype. RFLP-PCR utilizing <it>Mnl</it>I successfully characterized HbE at molecular level in six randomly selected samples.</p> <p>Conclusions</p> <p>Various HbE phenotypes are prevalent in Pakistan with HbEA and HbE/β thalassaemia representing the most common syndromes. Chromatography cannot only successfully identify hemoglobin E but also assist in further characterization into its phenotype including compound heterozygosity. Definitive diagnosis of HbE can easily be achieved through RFLP-PCR.</p