Winter Content Research Articles

Myoglobin content in skeletal muscles of hibernating ground squirrels rises in autumn and winter

The content of myoglobin (Mb) in skeletal muscles of Arctic Yakutian ground squirrel ( Citellus undulatus Pallas) was measured in the active euthermic summer and prehibernating autumn animals as well as in hibernating and awake animals in winter. The myoglobin content in winter, irrespective of the state of the animal, was found to be about three times higher than in summer. The content of myoglobin in autumn was also two-fold increased compared to summer, suggesting that high myoglobin level is necessary for hibernation. Analysis of biochemical data available suggests that the increase in myoglobin content in winter is probably related to a high oxygen demand of muscles at the first stage of arousal (non-shivering thermogenesis) when rectal temperature rises from 0 to 10–12°C. At this stage, the oxygen-dependent processes in muscles proceed under the conditions when peripheral blood flow is blocked and anaerobic glycolysis is switched off.

Photosynthesis in coffee ( Coffea arabica and C. canephora) as affected by winter and summer conditions

Photosynthetic and biochemical responses of potted plants of Coffea arabica cv Red Catuaı́ and C. canephora cv Kouillou were examined during winter and summer. There were large decreases in the photosynthetic rates of both cultivars from summer to winter, with more pronounced declines shown by Catuaı́. The photochemical efficiency of photosystem II, as evaluated by the ratio of variable to maximum chlorophyll fluorescence, decreased to a greater extent in Catuaı́ than in Kouillou during winter. This probably was a secondary effect due to the loss of the photosynthetic capacity, which was mostly determined by non-stomatal factors. In response to winter conditions, Kouillou accumulated three times more proline and ascorbate with no changes in the content of malonedialdehyde (MDA). Catuaı́ accumulated 160% more proline and 206% more MDA in winter in comparison to summer values, but there was no significant change in ascorbate levels. The content of chlorophylls and carotenoids did not change in response to natural seasonal acclimation. The leaf starch content in winter was higher by 53% in Catuaı́ than in Kouillou. Photosynthetic rates, as measured by oxygen evolution, were well correlated with starch content in Catuaı́, but not in Kouillou. When winter-grown leaves were darkened for 96 h, their normal starch levels were halved; this was accompanied by the restoration of the photosynthetic rates to levels similar to those found in summer in both cultivars, with a concurrent resumption of the photosystem II efficiency.

Seasonal changes in photosynthesis of young Cryptomeria japonica growing on ridges and foot-slopes

The influence of environmental factors affected by topography, especially light conditions in winter, on photosynthetic capacity of field-grown young Cryptomeria japonica trees was studied. Trees with a large increment in height growth tended to have current year needles with high photosynthetic capacity in the growing season. The change in the photosynthetic capacity from October to February, corresponding to the change in chlorophyll content, differed between trees planted near a ridge and on a foot-slope. There was a tendency for trees with a greater exposure to sunshine in winter, such as those near a ridge, to have a reduced chlorophyll content in winter. The photosynthetic capacity of 1-year-old needles of sample trees near a ridge did not recover as much as those on a foot-slope, even if the foliar nitrogen content was high. These results imply that the magnitude of winter injury on the photosynthetic apparatus differed according to the topographical conditions and strongly influenced the photosynthetic capacity during the next growing season.

Changes in plasma and pituitary levels of prolactin in the toad, Bufo japonicus, throughout the year with special reference to the breeding migration

Monthly surveys of the plasma prolactin level in Bufo japonicus at two localities, one in Tokyo and the other in Saitama Prefecture, revealed that the level was highest during the month of breeding in early spring with an additional peak recognized in autumn. The level was lowest during the winter torpid period before breeding and during the spring torpid period after breeding. The pituitary prolactin content observed in Tokyo also showed an annual cycle similar to the plasma prolactin, except that the content in winter was higher than that in summer. A further precise survey of the plasma prolactin level before and during the breeding period revealed that the level in male toads migrating toward the pond for breeding was as low as the level in torpid toads, and also that the level was elevated in only about 50% of migrating female toads. In the pond, almost all female and male toads showed high plasma prolactin levels. Soon after the females finished breeding and returned to land, the level declined to the baseline without exception. In contrast, many males retained high levels on land. The present results indicate that prolactin is not a water drive factor, at least in B. japonicus. Prolactin may, however, play a role in toad osmoregulation in water. There is a possibility that the high prolactin level in some of the migrating female toads is related to oviductal secretion, as some female toads ovulate during migration.

Studies of Native Fodder Grasses in Japan : IV. Hard seed content of some wild legumes under storage conditions

The hard seed content of Karasuno-endo (Vicia angustifolia L.) and Kawaraketsumei (Cassia mimosoides L.) which are being improved as fodder was investigated. Both immature and mature seeds of Karasuno-endo which had been stored for 1 or 3 months in the laboratory increased their hard seed content 0 to 62.7 % and 50 to 94.6 %, respectively. When immature seeds of Karasuno-endo were stored in a desiccator with water in the bottom of it, they retained their permeability entirely, but when stored with desiccant their hard seed content increased 0 to 99.3 % after 10 days of storage. Under storage condition in the laboratory mature seeds of Karasuno-endo reduced their percentages of hard seed in summer but didn't change them in other seasons. When they were stored with desiccant they showed high percentages of hard seed in every season. Mature seeds of Kawaraketsumei stored in the laboratory increased their hard seed content in winter and reduced in summer. Under dry storage condition with desiccant they reduced the hard seed content rapidly.

Soil Moisture and Water Utilization in Iowa1

SynopsisAverage water loss per day by runoff, percolation and evapo‐transpiration was 0.04 to 0.05 in winter and 0.18 to 0.20 in. in summer from soil samples taken in Iowa between February 1954 and November 1955. There was little change in soil moisture content in winter; small gains in spring were greater in corn than meadow. Decrease in summer was greater under corn than meadow, amounting to 3 to 4 in. Normal rainfall increased soil moisture content 2 to 3 inches in late summer and fall.

Studies on the polyploidy in the tea plant.

1. Several morphologicai and physiological characters of triploid varieties were compared with diploids. 2. There was no clear difference on the leaf size and shape between triploids and diploids, but triploid leaves were thicker than those of diploids. As a rule every internal tissue of triploid leaves was thicker than diploids. It is evident that triploid leaves had larger stomatas of which the distribution density vias lower, compared with diploids. 3. No difference between both the plants could be recognized on the res.istance to brown blight total nitrogen and tannin content in suminer, the reduced form vitamin C content in winter, and regeneration power in cutting. Triploid varieties was more hardy to cold, and some of them had extremely early growing spring bud. The water reserving ability of triploid leaves isolated from stem was greater than that of diploids in September, but the relation changed to be indifferent. in December. 4. Generally triploid fertility was very low but the difference of fertility between each triploid variety was noticed. The pollen grains of triploids showed high sterility. 5. From progenies of triploids, we discovered one aneuploid plant (2n=44). The characters were same like those of triploids and the meio. sis was proceeded abnormally. 6. With colchicine treatment to the growing point of germinated seeds, some tetraploid plants (2ri=60) were obtained. At present, tetraploid plants are growing slowly and they have, dwarf form.