2004 Fiscal Year Final Research Report Summary
Elucidation of gas diffusion and transport mechanisms in mangroves adapted to high salinity and anaerobic soil conditions
| Project/Area Number |
14560219
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
生物環境
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
KITAYA Yoshiaki Osaka Prefecture University, Graduate School of Life and Environmental Sciences, Associate Professor, 農学生命科学研究科, 助教授 (60169886)
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| Co-Investigator(Kenkyū-buntansha) |
SHIBUYA Toshio Osaka Prefecture University, Graduate School of Life and Environmental Sciences, Assistant Professor, 農学生命科学研究科, 助手 (50316014)
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| Project Period (FY) |
2002 – 2004
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| Keywords | mangrovs / hypocotyls / gas difusion / photosynthesis / leaf conductance / oxygen concentration / coastal ecosystem / gas exchange |
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| Research Abstract |
In order to carry out afforestation of mangroves efficiently, it is important to understand the growth characteristics of young seedlings as affected by environmental elements at plantation sites. Young seedlings of some mangrove species have well developed hypocotyls. The hypocotyls of the seedlings would have important role for their growth in an early growth stage. In the present study, we examined the effect of inhibition of gas exchange in the hypocotyls on oxygen concentrations in the hypocotyls and the roots and leaf conductance, using 6-12 months old seedlings of Bruguiera gymnorrhiza and Rhizophora stylosa. Plants were subjected to four treatments. There were 3-5 replicate plants per treatment. One group remained in the growing conditions as a control. In the other three treatments, the hypocotyls were either applied by silicon putty on the surfaces, shielded from sunlight or both applied putty and shielded. The oxygen concentrations were 19.2% and 12.7% in the hypocotyls and the roots, respectively, of B.gymnorrhiza. Oxygen concentration in the roots decreased to 3.1% with applying putty, and to 2.5% with applying putty and shielding. The leaf conductance of B.gymnorrhiza was 0.59 cm s^<-1> in the control at photosynthetic photon flux density of 500 to 1500 □mol m^<-2> s^<-1>. The conductance decreased to 0.16 cm s^<-1>, 0.46 cm s^<-1>, and 0.12 cm s^<-1> with applying putty, shielding, and applying putty and shielding, respectively. Decreases of oxygen concentrations in the hypocotyls and the roots and the leaf conductance were more remarkable with applying putty than that with shielding. R.stylosa showed the similar tendency to B.gymnorrhiza as affected by the same treatment. Therefore, extended submergence and shielding of the hypocotyls may inhibit gas exchange in leaves.
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