Effect of increasing salinity on growth and mineral composition of wheat varieties and role of sodium exclusion capacity in salt tolerance mechanisms

A few wheat varieties including two Japanese wheat varieties were evaluated for their salt tolerance at seeding stage, their behavior to increasing salinity levels and role of Na exclusion capacity in salt tolerance mechanisms. The wheat varieties were grown in nutrient solution and subjected to 0 (control), 25,75 and 125 mM NaCl salinity levels for 7 days. Although the shoot growth was reduced while Na contents were increased progressively with increasing salinity in all varieties, the varieties were quite different in their response. Salt tolerant va rieties maintained less reduction in their root and shoot growth and better water relations in their shoots than salt sensitive varieties under saline conditions. The wheat varieties were quite different in their Na exclusion capacity. Poor growth in salt sensitive varieties might be due to higher accumulation of Na in their shoots resulting from low Na exclusion capacity of roots, higher Na transport to shoot and/or inferior compartmentation capability

Chemical Changes of Dredged Soil in Kojima Lake from the Viewpoint of Soil Reaction

While dredged soil is increasing, the processing problem isn't solved. So it is expected to use effectively as the soil material. Although, to use dredged soil, the chemical characteristic must be grasped. It is because acidification cause material (pyrite) can be contained in dredged soil. It causes sulfulic ions when it touches air and has the possibility to become acidification. In this experiment, dredged soil in Kojima Lake was made clear that it contained in pyrite and acidified under the oxidation condition. Accordingly, when using dredged soil as ground resources, it is necessary to use as the soil material such as filling-up reclamation under the deoxidization condition

外国為替決済勘定 : "Nostro", "Vostro" および "Loro" account について

論

Phosphorus and Biomass Distribution, and P-efficiency by Diverse Brassica Cultivars Exposed to Adequate and P-stress Environment

To acclimate under orthophosphate (Pi) starved environment, plant species and cultivars display an elegant myriad of Pi-adaptive and rescue responses via reprioritizing internal Pi use and maximizing external Pi acquisition by reprogramming metabolism and restructuring root system architecture.Exploitation of considerable genetic diversity both between and within crop species and harnessing of these genetic variations can lead us to develop smart plants with improved P-acquisition, growth and yield under P-deprivation. To elucidate the effect of P-stress on plant growth, and P-efficiency under Pstarvation, 14 diverse Brassica cultivars were grown hydroponically in a climatically controlled chamber using sufficient (200 and 400 μM) and stress (10 and 20 μM) P-levels using ammonium phosphate (NH4H2PO4) as a P source. Cultivars showed differential growth behaviour in terms of biomass accumulation (shoot and root dry matter partitioning), percent distribution of Pi-concentration ([P]) and P-contents in plant parts (roots and shoots), and P-efficiency ratio (% PER)(relative shoot growth) indicating considerable genetic diversity among the tested Brassica cultivars. PER and the proportional increases in shoot dry matter (SDM) accumulation (SDMmax/SDMmin) in response to the P levels assisted in categorizing the cultivars into efficient and inefficient utilizers of the absorbed P from an ambient environment. Cultivars were classified into efficient responsive (ER), efficient non-responsive (ENR), non-efficient responsive (NER) and non-efficient non-responsive (NENR) by plotting ordination plots between PER and SDMmax/SDMmin under P-stress environment. Differential PER values at stress P levels corresponds to high P levels suggest that P efficiency mechanisms can be different from one cultivar to another within a give plant species and cultivars exhibiting high PER values are better choice to thrive under P-starvation

Process of Acid Sulfate Soil Formation from the Viewpoint of Moisture Conditions on Coastal Muddy Soil and a trial of it's Amelioration

According to recent soil survey data, it has been reported that acid sulfate soils cover areas of about 11,670,000 hectares all over the world and about 40% of those are in South-East Asia. Most of crops could not be grown on those areas without any amelioration due to low soil pH. This report consists of two parts. One is on acid sulfate soil formation in laboratory experiment. Another is on a trial of acid sulfate soil amelioration in field experiment. The results obtained on acid sulfate soil formation, in order to make clear the relationships between the process of oxidation of sulfur compounds and the moisture conditions (moisture suction) in coastal muddy soils, in laboratory experiment are summarized as follows; The concentration of sulfuric ions increase as oxidation of sulfur compounds contained in pyrite, etc. occurs, and as a consequence, the soil pH decreases in the coastal muddy soil (Fig.1). Especially, the soil pH decreased remarkably in the range of pF 2.3~3.4. The activity of soil microorganism takes part in this reaction by helping out with bringing about sulfur oxidation and formation of sulfuric ions. The pH decrease in the soil with autoclaved treatment was only slight at pF values lower than pF 3.0. Accordingly, it is concluded that the decrease of pH in coastal muddy soil occurred mainly due to soil microorganisms which oxidize sulfur compounds under the condition of higher-water than pF 3.0. The results of field experiment is summarized as follows; As a general rule, it is able to remedy the surface acidification of peat/acid sulfate soils by mixing lime dust with plough layer. However, the effect of mixed lime dust is easily disappeared in the area where the acidic ground water table is always high and moves up over the surface in rainy season. Therefore, it was carried out that several experiments for seeking protection against surface acidification due to capillary upward movement of acidic ground water by means of inserting a buffering layer of lime gravel (thickness of lime gravel layer =5㎝) between the top soil and the acidic subsoil (20 ㎝ depth) in the fields, Munoh series which is young acid sulfate soil, at the Narathiwat Land Development Center in South Thailand. The results of soil pH measurement carried out in the field in November of 1985, August of 1987 and September of 1990, it coincides with 2,4 and 7 years respectively after the beginning of the experiments, are shown in Table 3. In the plot of P2 and U1, application of lime dust to the plough layer can increase soil pH rapidly but it's residual effect is not so long. Within a 5 year period, the soil pH is likely to return to below 4. On the other hand, an underlaid lime gravel layer tends to improve the soil around the lime gravel only slight but steadily with time. Therefore, it is concluded that surface soil acidification caused by the upward movement of acidified ground water would be protected against, rapidly and continuously, by both mixing lime dust with plough layer and underlying lime gravel below plough layer. If acid sulfate soil areas would be used as upland fields, much of organic matters in soil are easily decomposed by drying. Therefore, it is suggested that it would be better for these areas to be used as paddy fields, also from the above results