This paper reports the first photosynthetic study of marestail in Jiuzhaigou. In this work, we used PAM fluorometry to examine photosynthetic rates of submerged and emerged marestail in three lakes. Three lakes were s...This paper reports the first photosynthetic study of marestail in Jiuzhaigou. In this work, we used PAM fluorometry to examine photosynthetic rates of submerged and emerged marestail in three lakes. Three lakes were studied across a gradient of water temperature, with low water temperature conditions in Grass Lake and Arrow Bamboo Lake, and higher water temperature in Five Colored Lake. In the field, electron transport rates （ETRmax） were measured as rapid light curves （RLCs） by in situ yield measurements. Submerged and emerged marestail showed higher photosynthetic activity in Five Colored Lake compared to the other lakes, a response consistent with the adaptation of marestail in Five Colored Lake to high water temperature. The optimal temperature for photosynthesis of submerged marestail in Jiuzhaigou was about 12 ~C. Non- photochemical quenching （NPQ） of submerged and emerged marestail increased with increasing water temperature. Maximum quantum yield （Fv/Fm） of submerged marestail in Five Colored Lake showed full recovery at 170o h due to higher NPQ. Further, the chlorophyll a for submerged marestail was the highestin Grass Lake and the lowest in Five Colored Lake. These results indicate that in different lakes the function of these aquatic plants is associated with a diversity of place-dependent environmental conditions, especially water temperature that leads to pronounced differences in the plant＇s ecophysiological reactions.展开更多
Tolpyralate is a benzoylpyrazole, 4-hydroxyphenyl-pyruvate dioxygenase inhibitor, and a herbicide registered for use in corn. The efficacy of tolpyralate plus atrazine to provide full-season residual control of glypho...Tolpyralate is a benzoylpyrazole, 4-hydroxyphenyl-pyruvate dioxygenase inhibitor, and a herbicide registered for use in corn. The efficacy of tolpyralate plus atrazine to provide full-season residual control of glyphosate-resistant (GR) Canada fleabane in corn is not known under Ontario environmental conditions. Five field trials were completed over a two-year period (2018-19) in south-western Ontario on farms with confirmed GR Canada fleabane [Conyza canadensis (L.) Cronq.] populations to determine if tolpyralate + atrazine provides full-season residual control of GR Canada fleabane in corn. Corn injury was less than 10% with all treatments. At 4 weeks after application (WAA), tolpyralate (30 g·ai·ha−1), tolpyralate (40 g·ai·ha−1), and atrazine (560 g·ai·ha−1) controlled GR Canada fleabane 64, 78 and 72%, respectively. A tank mix of tolpyralate + atrazine at both rates improved GR Canada fleabane control to 94%. Saflufenacil/dimethenamid-p, mesotrione + atrazine, and dicamba/atrazine controlled GR Canada fleabane 99, 95 and 92%, respectively. At 8 WAA, tolpyralate (30 g·ai·ha−1), tolpyralate (40 g·ai·ha−1) and atrazine (560 g·ai·ha−1) controlled GR Canada fleabane 83, 88, and 83%, respectively (Table 2). The tank mixes of tolpyralate (30 g·ai·ha−1) + atrazine (560 g·ai·ha−1) and tolpyralate (40 g·ai·ha−1) + atrazine (560 g·ai·ha−1) controlled GR Canada fleabane 94, and 97%, respectively, 8 WAA which was similar to saflufenacil/dimethenamid-p, mesotrione + atrazine and dicamba/atrazine. There was no treatment difference for corn yield. Based on these results, tolpyralate (40 g·ha−1), tolpyralate (30 g·ha−1) + atrazine and tolpyralate (40 g·ha−1) + atrazine, applied PRE, provided similar control of GR Canada fleabane as current industry standards at 8 WAA.展开更多
基金funded by the International Program of the Ministry of Science and Technology of China (2010DFA91280)111 Project(B08037)
文摘This paper reports the first photosynthetic study of marestail in Jiuzhaigou. In this work, we used PAM fluorometry to examine photosynthetic rates of submerged and emerged marestail in three lakes. Three lakes were studied across a gradient of water temperature, with low water temperature conditions in Grass Lake and Arrow Bamboo Lake, and higher water temperature in Five Colored Lake. In the field, electron transport rates （ETRmax） were measured as rapid light curves （RLCs） by in situ yield measurements. Submerged and emerged marestail showed higher photosynthetic activity in Five Colored Lake compared to the other lakes, a response consistent with the adaptation of marestail in Five Colored Lake to high water temperature. The optimal temperature for photosynthesis of submerged marestail in Jiuzhaigou was about 12 ~C. Non- photochemical quenching （NPQ） of submerged and emerged marestail increased with increasing water temperature. Maximum quantum yield （Fv/Fm） of submerged marestail in Five Colored Lake showed full recovery at 170o h due to higher NPQ. Further, the chlorophyll a for submerged marestail was the highestin Grass Lake and the lowest in Five Colored Lake. These results indicate that in different lakes the function of these aquatic plants is associated with a diversity of place-dependent environmental conditions, especially water temperature that leads to pronounced differences in the plant＇s ecophysiological reactions.
文摘Tolpyralate is a benzoylpyrazole, 4-hydroxyphenyl-pyruvate dioxygenase inhibitor, and a herbicide registered for use in corn. The efficacy of tolpyralate plus atrazine to provide full-season residual control of glyphosate-resistant (GR) Canada fleabane in corn is not known under Ontario environmental conditions. Five field trials were completed over a two-year period (2018-19) in south-western Ontario on farms with confirmed GR Canada fleabane [Conyza canadensis (L.) Cronq.] populations to determine if tolpyralate + atrazine provides full-season residual control of GR Canada fleabane in corn. Corn injury was less than 10% with all treatments. At 4 weeks after application (WAA), tolpyralate (30 g·ai·ha−1), tolpyralate (40 g·ai·ha−1), and atrazine (560 g·ai·ha−1) controlled GR Canada fleabane 64, 78 and 72%, respectively. A tank mix of tolpyralate + atrazine at both rates improved GR Canada fleabane control to 94%. Saflufenacil/dimethenamid-p, mesotrione + atrazine, and dicamba/atrazine controlled GR Canada fleabane 99, 95 and 92%, respectively. At 8 WAA, tolpyralate (30 g·ai·ha−1), tolpyralate (40 g·ai·ha−1) and atrazine (560 g·ai·ha−1) controlled GR Canada fleabane 83, 88, and 83%, respectively (Table 2). The tank mixes of tolpyralate (30 g·ai·ha−1) + atrazine (560 g·ai·ha−1) and tolpyralate (40 g·ai·ha−1) + atrazine (560 g·ai·ha−1) controlled GR Canada fleabane 94, and 97%, respectively, 8 WAA which was similar to saflufenacil/dimethenamid-p, mesotrione + atrazine and dicamba/atrazine. There was no treatment difference for corn yield. Based on these results, tolpyralate (40 g·ha−1), tolpyralate (30 g·ha−1) + atrazine and tolpyralate (40 g·ha−1) + atrazine, applied PRE, provided similar control of GR Canada fleabane as current industry standards at 8 WAA.
