强潮区较高纬度移植红树植物秋茄的生理生态特性

以中国红树林引种最北界的乐清湾西门岛海域为研究地点,选择黄零为1.96、1.66和1.35 m 3个高程断面(每个潮水周期平均淹水时间分别为3.18、3.65、4.07 h),研究了1年生和4年生秋茄的生长、叶片的光合色素和保护酶活性、植株可溶性糖含量、游离氨基酸含量、离子含量等指标的变化。结果表明,当滩涂高程为黄零1.66 m以上时,每个潮水周期平均淹水时间低于3.65 h,1年生和4年生秋茄幼苗均可生长;当滩涂高程为低于黄零1.35 m时,每个潮水周期平均淹水时间高于4.07 h,1年生秋茄幼苗仍能正常生长,而4年生秋茄叶片叶绿素、类胡萝卜素总量、茎叶中的可溶性总糖和游离氨基酸含量、过氧化物酶(POD)活性以及K+/Na+比均显著降低,同时,叶片中的丙二醛(MDA)和茎、叶中Na+含量均快速上升,导致了生长缓慢。总体上说,较大树龄秋茄可生长在高程为黄零1.66 m以上,其原因是植株在每个潮水周期平均淹水时间少于3.65 h时仍能够维持正常的碳氮代谢。

Ecophysiological characteristics of higher-latitude transplanted mangrove Kandelia candel in strong tidal range area

Ximen island of Yueqing bay, the northern boundary of artificially planted mangroves, was chosen as the study site. Changes of 1- and 4-year-old Kandelia candel at the tidal level of 1.96, 1.66 and 1.35 m above the zero tidal level of Yellow Sea (Waterlogging time at this tidal level are 3.18, 3.65 and 4.07 h per-tide-cycle respectively) on growth, photosynthetic pigments, activities of protective enzymes in leaves, contents of total soluble sugars and free amino acid and ion contents in leaves and stems were investigated. The results showed that the tidal level of 1.66 m above the zero tidal level of Yellow Sea was suitable for planting Kandelia candel, because the waterlogging time at this tidal level was less than 3.65 h per-tide-cycle. When the tidal level was 1.35 m above the zero tidal level of Yellow Sea, the waterlogging time at the tidal level was 4.07 h per-tide-cycle, which caused a series of effects. A decrease in the contents of chlorophyll, carotenoid, total soluble sugars and free amino acid, the activities of peroxidase (POD) in leaves, and the ratio of K⁺/Na⁺ in stems and leaves of 4-years-old Kandelia candel were detected. Moreover, a rapid increase in the contents of malondialdehyde (MDA) in leaves and Na⁺ concentration both in leaves and stems of 4-years-old Kandelia candel were found. Based on results listed above, a growth retard was detected when the waterlogging time was 4.07 h per-tide-cycle for 4-year-old Kandelia candel. However, this growth retard was not found in 1-year-old Kandelia candel under the same waterlogging time. Therefore, it is concluded that the older Kandelia candel could grow at 1.66 m above the zero tidal level of Yellow Sea, which is due to the maintaining of normal carbon and nitrogen metabolism under waterlogging time (less than 3.65 hours per-tide-cycle) at this tidal level.