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extracted with EDTA) to total primary production (TPP) were rneasured using "C-tracer to estirnate the ratio for each fraction of organic carbon photosynthetically produced by microphytobenthos and phytoplankton. TEOC for rn.icrophytobenthos ranged frorn 4 2 to 73% of TPP and was rnade up mostly of 14C-Colloidal-OC The TEOC/TPP for phytoplankton ranged frorn 1.5 to 220,). The ratio of I4C-EPS to I4C-CoUoidal-OC for rnicrophytobenthos was 41 to 53%, and for phytoplankton was 4.4 to 24%. Algal species in the transitional phase were used for experiments because microphytobenthos Nitzschia hybridaeformis most abundantly produced TEOC and EPS in the transitional phase during growth in experirnents studying the effect of the growth phase. By using EDTA for the extraction of extraceUular organic matter, it beComes clear that excretion of colloidal organic matter by rnicrophytobenthos has always been underestimated. These results suggest that the large arnount of TEOC containing EPS produced by microphytobenthos plays a more mportant role than secretion of phytoplankton as a source of organic carbon for heterotrophic organisms in the intertidal-flat ecosystem.

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Limnological features of Lake Puma Yum Co, a typical alpine lake located at the altitude of 5030 m in the Tibetan Plateau, China, are described based on the fi ndings of the second expedition in September 2004. The lake surface is about 280 km 2 and maximal depth is 65 m. Total infl ow just after the rainy season was estimated to be about 860 000 m 3 day, and the lake water was drained from a newly excavated channel at a rate of 960 000 m 3 day −1. We may have to expect undesirable lowering of the water level by this new drainage, especially in the dry season. Thermocline developed from 20 to 30 m depth, and the euphotic zone reached the 50 m depth. Dissolved oxygen in surface water was supersaturated as in productive lakes, although there were no large point and nonpoint sources of nutrient in the catchment. Vertical distribution of phytoplankton biomass and primary production suggested the presence of photoinhibition. What should be noted about the fl ora and fauna is that a Chara zone and a shell zone were distributed at about 30 or 40 m of depth.

Endogenous JA production is not necessary for wound-induced expression of JA-biosynthetic lipase genes such as DAD1 in Arabidopsis. However, the JA-Ile receptor COI1 is often required for their JA-independent induction. Wounding is a serious event in plants that may result from insect feeding and increase the risk of pathogen infection. Wounded plants produce high amounts of jasmonic acid (JA), which triggers the expression of insect and pathogen resistance genes. We focused on the transcriptional regulation of DEFECTIVE IN ANTHER DEHISCENCE1 and six of its homologs including DONGLE (DGL) in Arabidopsis, which encode lipases involved in JA biosynthesis. Plants constitutively expressing DAD1 accumulated a higher amount of JA than control plants after wounding, indicating that the expression of these lipase genes contributes to determining JA levels. We found that the expression of DAD1, DGL, and other DAD1-LIKE LIPASE (DALL) genes is induced upon wounding. Some DALLs were also expressed in unwounded leaves. Further experiments using JA-biosynthetic and JA-response mutants revealed that the wound induction of these genes is regulated by several distinct pathways. DAD1 and most of its homologs other than DALL4 were fully induced without relying on endogenous JA-Ile production and were only partly affected by JA deficiency, indicating that positive feedback by JA is not necessary for induction of these genes. However, DAD1 and DGL required CORONATINE INSENSITIVE1 (COI1) for their expression, suggesting that a molecule other than JA might act as a regulator of COI1. Wound induction of DALL1, DALL2, and DALL3 did not require COI1. This differential regulation of DAD1 and its homologs might explain their functions at different time points after wounding.