潮汐淹水时间对秋茄幼苗生长的影响

模拟正规半日潮淹水的条件下,不同淹水时间对秋茄Kandelia candel(L.)Druce]幼苗生长的影响.应用沙和土两种培养基质,制备盐度为15的人工海水栽培幼苗培养时间为70 d.不淹水(0 h)和长时间淹水(>8 h)对秋茄幼苗的生长有一定的抑制作用,而短时间淹水(淹水2~4 h)对幼苗生长有所促进.较长时间的淹水可促进贮气根的数量增加和长度的增长.在当前培养条件下,秋茄幼苗生长的最佳淹水时间是每个潮水循环淹水2~4 h.2 h处理的沙培秋茄幼苗总生物量和成熟叶面积最大,胚轴失重最小,土培幼苗也有相应的变化趋势.秋茄幼苗生长的临界淹水时间是每个潮水循环淹水8 h.秋茄幼苗有较强的抗淹水能力,适当的淹水对其生长有利.

Influence of waterlogging time on the growth of Kandelia candel seedlings

Influence of waterlogging time on the growth of Kandelia candel (L.) Druce seedlings grown for 70 d in artificial-tidal tanks simulated semidiurnal tide under greenhouse was studied. Sand and soil acted as the substrate and artificial seawater with the salinity of 15 were used in cultivation. Shorter waterlogging time (inundated for about 2~4 h) promoted the growth of K. candel seedlings, while longer time (inundated more than 8 h) or no waterlogging (0 h) inhibited their growth. The number and length of aerating roots increased with the increase of waterlogging time. In current condition, the optimal waterlogging time for the growth of K. candel seedlings was about 2~4 h in every tide cycle. Comparing with other treatments, seedlings in (2 h) sanded treatments obtained the highest biomass, made the lowest mass loss of hypocotyl and broadened the photosynthetic area by increasing area per leaf after 70d cultivation. And the soil treatments had the similar tendency. However, waterlogging for (8 h) in every tide cycle is critical for normal development of seedlings. K. candel seedlins were highly tolerant to waterlogging and a proper waterlogging was beneficial to the growth of K. candel seedlings.