Increasing Sea Water Concentrations Research Articles

砂耕及び土耕栽培におけるバラの耐塩性

Experiments were conducted to determine the effect of diluted sea water on the growth and flowering of the ‘Sunlight’ rose cultivar. One-year old ‘Sunlight’ cuttings or ‘Sunlight’ grafted onto Rosa multiflora rootstocks were planted in a wooden container (40×40×20cm) filled with sand or soil. Sea water diluted with Hoagland′s solution and also tap water was used for both sand and soil cultures. Each solution contained 0, 100, 250, 500, 1000, 2000 and 3000ppm Cl. Treatments were continued for approximately 60 days beginning April 30, 1974. Salt injury was not found at 0, 100 and 250ppm Cl. In grafted plants, injury developed in both sand and soil cultures above 500ppm Cl. On own-root plants, injury was observed above 500ppm Cl in sand culture and above 1000ppm Cl in soil culture. The degree of injury was intensified as sea water was raised from 500 or 1000 to 3000ppm Cl. Symptoms such as interveinal chlorosis, marginal and tip burns, and dieback first appeared on the lower leaves and progressed upwards. They further developed on the current shoots of severely injured plants. Generally the injury was more severe in sand than in soil cultures, and on grafted plants than on own-root plants, and highly correlated with Na and Cl in old and young leaves. The Cl and exchangeable K, Mg and Na, and EC values of the soil increased with increasing sea water concentrations.

キクの耐塩性

Experiments were conducted to determine the effect of various concentrations of sea water on growth and flowering of Chrysanthemum morifolium Ramat. ‘Seikonohana’ in sand and soil cultures. The plant height and top fresh weight of flowering plants grown in sand and soil decreased above 250ppm Cl of sea water, and the flowering was markedly delayed above 2000ppm Cl. Salt injury appeared on the leaves at 500ppm Cl in sand culture and at 2000ppm Cl in soil culture 64 days after the beginning of treatments, and became more severe with increasing sea water concentrations. The intensity of the injury was less in soil culture than in sand culture. There was an increase in Mg, Na and Cl content in the leaves at the higher concentrations of sea water in sand and soil cultures. At the end of the experiment the content of Cl, exchangeable Mg and Na in the soil, and the EC values increased with increasing sea water concentrations.

エダマメの耐塩性

Experiments were conducted to determine the effect of diluted sea water on the germination, growth and yield of green soybeans. The germination rate was not significantly different at 0 to 3, 000ppm Cl 2 days after starting the germination test. Seedlings were grown in sand culture for 20 days after seeding. The top dry weight was greatest at 250 and 500ppm Cl. Green soybeans were grown in sand and soil cultures. Salt injury in sand culture was not found at 0 and 100ppm Cl. However, it was slight at 250ppm Cl, and became much more severe with increasing sea water concentrations. The seed fresh weight was greatest at 0 to 250ppm Cl in sand culture and at 0 to 500ppm Cl in soil culture. There was an increase in Na and Cl content in the leaves in sand and soil cultures when sea water concentrations were at high Cl levels. The content of Cl and exchangeable Na, and EC value of the soil increased with increasing sea water concentrations.

The effect of seawater on the metabolism of some seashore and inland mosses.

Photosynthesis and protein synthesis were determined, by measuring uptake and incorporation of radioactive bicarbonate and L-valine, in some seashore and inland mosses after treatment with artificial seawater. In the inland species there was a progressive decline in both processes with increasing seawater concentration. Photosynthesis in the seashore mosses Grimmia maritima and Tortella flavovirens was unaffected by increasing seawater concentration, and supralittoral Ulota phyllantha was less seriously affected than epiphytic material from a subcoastal location. There was a marked decline in chlorophyll content and cessation of photosynthesis in the inland moss G. pulvinata after 3 days' seawater treatment whereas material treated with deionised water showed increased photosynthesis and chlorophyll levels over the same period. In G. maritima both chlorophyll levels and photosynthesis remained relatively unaffected by treatment with seawater for 4 days. Treatment of G. pulvinata with seawater and NaCl led to increased leakage of photosynthetic products to the external solution but this was insufficient to explain the reduction in carbon retained by the plant. The seawater-induced disruption of metabolism in inland bryophytes is believed to be primarily due to the uncontrolled entry of toxic ions into the moss cells whereas seawater tolerance in the seashore species probably reflects the possession of an efficient intracellular cation control mechanism.

Salinity Preference: an Orientation Mechanism in Salmon Migration

An examination of the modal salinity preferences of five Pacific salmon species showed the following pattern of temporal changes. The sequence began with a preference for fresh water, then changed gradually, in the direction of increasing seawater concentration. The terminal pattern indicated a preference for water of open ocean concentration. This temporal progression of salinity preference changes was shown to parallel closely the salinity gradients typical of river outflows through which young salmon pass on their way to the ocean. On the basis of this evidence the following orientation mechanism was proposed: that juvenile Pacific salmon are able to use estuarial salinity gradients as one of the directive cues in their seaward migration.