<正>对3种不同林龄阶段的马尾松林下枯落物储量及其持水特性进行分析。结果表明：枯落物储量中近熟林、中龄林、幼林分别为32.20、30.59、22.27t/hm2；同一林分不同种类枯落物最大持水量差异明显；枯落物吸水速度随浸泡时间的延长而降低，30min内吸水速度最快，枯落物吸水速度与其浸泡时间相关性极高；在充分吸水条件下，不同林龄不同层次、不同种类枯落物蒸发量有所差异，保水周期为7～10d；林下枯落物最大持水能力随林龄的增大而增加，幼龄林、中龄林、近熟林分别为53.28、71.91、77.49t/hm2，分别相当于水深为5.33、7.19、7.75mm。

The effects of controlling dissolved oxygen tension(DOT) on cellulase production by Trichoderma reesei were studied with 10 g/L pulp. The moore content of carbon dioxide and oxygen in off-gass and cellulase activity were mensurated. The results showed that at aeration rate of 25 L/(h～L), the DOT was too low for 22-40 h, but it was high for 0-15 h and 45 h to end. The moore content of carbon dioxide in the gas was above 0. 8% for 45-80 h, and it went against the growth of mycelium. When the aeration was adjusted to control DOT, cellulase activity was effectively increased and the time of cellulase production was evidently shorten. At DOT of 20%-30%, the content of carbon dioxide in the gas was dropped to about 0.4%, the growth and metabolize of mycelium was better and filter paper activity (FPA) reached 3.54 U/mL. It was 28.7% higher than 2. 75 U/mL of the unchanged one. It was found that the optimnm time for harvest of cellulase was shortened from 84 h to 72 h.