Abstract
1. Photosynthesis and respiration rate of rooted aquatic plants were measured by the light and dark bottle method. The efficiency and limitations of the methodwere discussed.2. The maximum rate of photosynthesis at light saturation, 38mg O2/g dry weight/hr, was obtained in Hydrilla verticillata in August. Usually the rate was 5-10mg O2/g/hr in most species in summer. In general, the photosynthetic activity of aquatic macrophytes was 1/2 to 1/10 of that of land plants, when compared on a leaf area basis.3. Winter buds or turions, produced by certain species such as Hydrilla verticillata and Ceratophyllum demersum, showed lower metabolic rates as compared with vegetative shoots of the same species.4. Two types of profile structure were found in aquatic plant communities, respectively corresponding to the grass- and herb-types of terrestrial communities. The former is made by such linear-leaved species as Vallisneria asiatica, while the greater part of the aquatics forms the community having the latter type of structure, as illustrated by the example of Potamogeton crispus. The concentration of leaf biomass in the surface stratum characteristic to the latter type is exaggerated by the floatinghabit of shoot tips in submerged higher plants.5. Total photosynthesis and respiration of a community were measured by the in situ technique. In the upper part of the community the photosynthetic rate was high, while it became lower toward the basal part. The difference was mostly attributed to the gradient of physiological activity inherent to different depths of the Table 4. Average daily values (g day matter/m2/day) of gross production (Pg), net production (Pn) and respiration (R) of Potamogeton crispus and Vallisneria asiatica communities. Figures in the brackets show relative values. community. The respiration rate, on the other hand, seemed fairly constant throughout the depths.6. Daily rates of dry matter production and respiration loss of the whole community were estimated. In an early stage of a Vallisneria asiatica community in June, the net production was -0.59g dry matter/m2/day, suggesting the vigorous consumption of storage substances in clonal organs. A fully developed Potamogeton crispus community (total biomass:112g dry weight/m2 or 1.9g chlorophyll/m2. LAI:4.2m2/m2) produced 0.50g dry matter/m2/day in May. Corresponding gross production was 0.66 and 2.39g dry matter/m2/day, respectively.
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Claims 14
Claim · model-written summary
Hydrilla attained maximum photosynthesis of 38mg O2/g dry weight/hr in August.
- Taxon
- Hydrilla verticillata
Hydrilla verticillatae0 - Outcome
- maximum rate of photosynthesise0
- Direction
- maximume0
- Value
- 38mg O2/g dry weight/hre0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maximum rate of photosynthesis at light saturation, 38mg O2/g dry weight/hr, was obtained in Hydrilla verticillata in August”
Claim · model-written summary
Most species usually had photosynthesis of 5-10mg O2/g/hr in summer.
Verbatim
e0“Usually the rate was 5-10mg O2/g/hr in most species in summer”
Claim · model-written summary
Aquatic macrophyte photosynthetic activity was 1/2 to 1/10 of land plants on a leaf-area basis.
Verbatim
e0“photosynthetic activity of aquatic macrophytes was 1/2 to 1/10 of that of land plants, when compared on a leaf area basis”
Claim · model-written summary
Hydrilla turions had lower metabolic rates than vegetative shoots.
- Taxon
- Hydrilla verticillataHydrilla verticillatae0
- Organ / stage
- Winter buds or turionse0
- Outcome
- metabolic ratese0
- Direction
- lowere0
- Comparator
- vegetative shootse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Winter buds or turions, produced by certain species such as Hydrilla verticillata and Ceratophyllum demersum, showed lower metabolic rates as compared with vegetative shoots of the same species”
Claim · model-written summary
Ceratophyllum turions had lower metabolic rates than vegetative shoots.
- Taxon
- Ceratophyllum demersum
Ceratophyllum demersume0 - Organ / stage
- Winter buds or turionse0
- Outcome
- metabolic ratese0
- Direction
- lowere0
- Comparator
- vegetative shootse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Winter buds or turions, produced by certain species such as Hydrilla verticillata and Ceratophyllum demersum, showed lower metabolic rates as compared with vegetative shoots of the same species”
Claim · model-written summary
Aquatic communities had two profile structure types.
Verbatim
e0“Two types of profile structure were found in aquatic plant communities”
Claim · model-written summary
Vallisneria formed the linear-leaved grass type of community.
- Taxon
- Vallisneria asiatica
Vallisneria asiaticae0 - Outcome
- linear-leaved speciese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The former is made by such linear-leaved species as Vallisneria asiatica”
Claim · model-written summary
Potamogeton illustrated the herb type of community.
- Taxon
- Potamogeton crispus
Potamogeton crispuse0 - Outcome
- latter type of structuree0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“aquatics forms the community having the latter type of structure, as illustrated by the example of Potamogeton crispus”
Claim · model-written summary
Community photosynthesis declined from upper to basal layers.
Not reportedTaxon
Verbatim
e0“In the upper part of the community the photosynthetic rate was high, while it became lower toward the basal part”
Claim · model-written summary
Community respiration was fairly constant with depth.
Not reportedTaxon
Verbatim
e0“The respiration rate, on the other hand, seemed fairly constant throughout the depths”
Claim · model-written summary
Early Vallisneria community net production was -0.59g dry matter/m2/day in June.
- Taxon
- Vallisneria asiaticaVallisneria asiaticae0
- Outcome
- net productione0
- Value
- -0.59g dry matter/m2/daye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In an early stage of a Vallisneria asiatica community in June, the net production was -0.59g dry matter/m2/day”
Claim · model-written summary
Developed Potamogeton community produced 0.50g dry matter/m2/day in May.
- Taxon
- Potamogeton crispusPotamogeton crispuse0
- Outcome
- producede0
- Value
- 0.50g dry matter/m2/daye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A fully developed Potamogeton crispus community (total biomass:112g dry weight/m2 or 1.9g chlorophyll/m2. LAI:4.2m2/m2) produced 0.50g dry matter/m2/day in May”
Claim · model-written summary
Vallisneria gross production was 0.66g dry matter/m2/day.
- Taxon
- Vallisneria asiaticaVallisneria asiaticae1
- Outcome
- gross productione0
- Value
- 0.66e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corresponding gross production was 0.66 and 2.39g dry matter/m2/day, respectively.”
e1“Vallisneria asiatica community”
Claim · model-written summary
Potamogeton gross production was 2.39g dry matter/m2/day.
- Taxon
- Potamogeton crispusPotamogeton crispuse1
- Outcome
- gross productione0
- Value
- 2.39g dry matter/m2/daye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corresponding gross production was 0.66 and 2.39g dry matter/m2/day, respectively.”
e1“Potamogeton crispus community”