伪潜育土季节性滞水条件下大冷杉毫根动态的研究(Abies grandis Lindl.)

本文对一个25年生大冷杉林在伪潜育土至45cm矿质土壤里,从1987年晚秋滞水期至1988年生长旺盛期的毫根量动态及化学组成变化进行了研究。 滞水期土壤中死根量(5558kg DS/ha)显著高于活根量(3594kg DS/ha)。生长旺盛期初,活根量增加约50％,死根量降低约27％。经过夏季至生长旺盛期末,活根量仍略有增加,死根量继续降低。毫根化学组成分析显示,滞水期活根中K、Mg及Zn离子含量显著低于生长旺盛期,Mn离子含量则明显高于生长旺盛期。这一结果表明,除了与季节性相关的生长节奏因素外,大冷杉毫根生物量的变化主要是由滞水状况所致。

DYNAMIC OF FINE ROOTS OF GRAND FIR (ABIES GRANDIS LINDL. ) TO PERIODICAL WATERLOGGING IN A PSEUDOGLEY SITE.

The dynamic of fine root biomass in mineral soil up to 45cm and their chemical composition were investigated in a 25 years old grand fir stand on a pseudogley soil from the waterlogged period to the vegetation period (November 1987-September 1988) . Under waterlogging the fine roots had considerably higher dead mass (5558 kg DS/ha) than living mass(3594 kg DS/ha). At the start of the vegetation period the total mass of the living fine roots increased by 50% and the total mass of the dead fine roots decreased by 27%. A further shift, although smaller, could be observed through the summer towards the end of the vegetation period. The influence of waterlogging on the vitality of the fine foots was recognizable in their chemical composition. During waterlogging the living fine roots showed distinctly less K, Mg, Zn, but higher Mn contents than that during the vegetation period. We conclude that the large fluctuation of the fine root mass was due to the water saturation although some yearly periodic root growth occur.