ABSTRACT
With a large artificial climate chamber, we examined the effects of warming (control, +1.5 â, +2.0 â), photoperiod (10, 14, 18 h) and nitrogen addition (0, 5, 10, 20 g N·m-2·a-1) on the main phenological phases of Quercus mongolica in Northeast China. The results showed that 1.5 and 2.0 â warming significantly advanced the bud swelling stage and delayed the leaf fully coloring stage, which prolonged the growing season. The extended days increased with the increases of warming range. Photoperiod significantly affected autumn phenology (leaf coloration onset stage, leaf coloration in general stage, leaf fully coloring stage). Compared with photoperiod of 14 h, short photoperiod (10 h) significantly delayed leaf coloration onset stage by 7.0 d, and prolonged the peak of growth season. Nitrogen addition significantly advanced the bud swelling stage, bud opening stage, first leaf unfolding stage and full leaf unfolding stage. The leaf fully coloring stage was significantly delayed by 9.5 d only at the high nitrogen level of 20 g N·m-2·a-1, indicating that high nitrogen addition prolonged the growing season of Q. mongolica. The synergistic effects of warming and high nitrogen addition (20 g N·m-2·a-1) significantly delayed the leaf fully coloring stage, which prolonged leaf coloration stage, and the synergistic effects of warming and short photoperiod, the synergistic effects of nitrogen addition and short photoperiod. The synergistic effects of warming, nitrogen addition and short photoperiod all significantly delayed the leaf coloration onset stage, which relatively prolonged the peak of growing season.
Subject(s)
Quercus , Photoperiod , Nitrogen , Climate , Plant Leaves , Seasons , Climate Change , Temperature , TreesABSTRACT
Five hundred and six fresh fecal samples were collected from Lu'an, Fuyang, Suzhou, Chizhou, Wuhu, Chuzhou and Bozhou in Anhui Province, and detected firstly by direct smear microscopy. The microscopy-positive samples were amplified by nested PCR targeting the triosephosphate isomerase (TPI) and glutamate dehydrogenase(GDH) genes. The positive PCR products were sequenced in both directions. The sequences were analyzed by ClustalX 1.81 for sequence alignment and the neighbor-joining trees were constructed by Mega 5.05. Thirty-two out of 506 fecal specimens were diagnosed as Giardia-positive by microscopy with an infection rate of 6.3%. 23 and 16 of the samples were typed as assemblage E by the TPI (530 bp) and GDH (450 bp) genes, respectively. These findings indicated that there was a different distribution of subtypes of assemblage E in different areas. The zoonosis genotypes such as assemblage A or B was not found in the present study.
