In recent years, Andigena (S. tuberosum ssp. andigena) has attracted the attention of potato breeders as a material for improving yield capacity. The autors reported that one of Andigena strains (W553-4) had high yield capacity and an efficient canopy structure for light transmission. In this experiment, W553-4 was planted to estimate its characteristics of dry matter production and canopy structure at the three population densities (Table 1). 1. W553-4 had large dry weight of stem, root and stolon, and later tuber initiation by 15 to 20 days compared with Norin N0.1. The tuber initiations at the medium and the high density, however, were earlier by several days than that at the low density, and after the middle of August, their total dry weights were considerably large (Fig. 1). In addition, W553-4 showed a tendency that at the higher density, percentages of tuber dry weight were high and those of shoot (leaf and stem) dry weight were low (Fig. 2). 2. The peaks of crop growth rate (CGR) and tuber growth rate (TGR) for W553-4 were later than those for Norin No. 1 (except that of CGR at the low density), and values at the medium and the high density were rather high. W553-4 had large differences in leaf area index (LAI) among densities, and showed rapid decline of net assimilation rate (NAR) at the early growing season (Fig. 3). 3. For photosynthetically-active radiation intercepted by crops during the experimental periods (ΔPAR) and efficiency of dry matter accumulation per ΔPAR (E_PAR), the medium density for both W553-4 and Norin No. 1 was high (Table 2). As for each experimental period, CGR was correlated positively with ΔPAR during emergence to the tuber initiation, and also closely related to E_PAR during all periods (Fig. 4). 4. Canopy structures for W553-4 were efficient for light transmission compared with those for Norin No. 1. Large amount of leaf area distributed in lower layers at the low density, and leaf area at the medium and the high density distributed uniformly over all layers with small light extinction coefficient (K) values (Fig. 5). For compound leaf area, W553-4 had large differences among densities, and considerably large leaves existed at the low density (Fig. 6).

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Studies were carried out to examine the differences between the weight of seeds obtained from the panicles artificially restricted the kernel number and those obtained without restriction. The studies were also done to examine the differences of the F₁ seed weight and the plant height of F1 seedlings between reciprocal crossings. Results obtained are as follows : 1. There was no statistically significant differences between the weight of seeds obtained from the panicles restricted the kernel number and those obtained without restriction (Table 1). 2. Hybrid seeds obtained from the cross combinations whose maternal seed weight was heavier than that of the paternal variety were heavier than that from the reverse cross combinations (Table 1). 3. A reciprocal difference was found in plant height of many F₁ seedlings. That is, the plant height of F₁ obtained from the cross combinations whose maternal variety was Zenith showed a tendency that it was taller than that from the reverse cross combinations. On the other hand, reciprocal difference was not found in the culm length (Table 2). 4. A remarkable heterosis was observed in some crossings. The most excellent F₁ gave an increase 70% higher yield than that of the parents (Table 3).

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Five experiments on the method of tillage were conducted to determine the growth and yields of sugar beets to changes of soil physics from 1979 to 1983 in Sapporo. The treatments (reduced tillage and normal tillage : both planted in late 10 days of April and conventional cultivation : planted in early 10 days of May) were set in black andosol. Sugar beets were grown with the method of transplanting. The following results were obtained. 1. Soil hardness between rows was harder in reduced tillage than in normal one, and solid ratio larger and air ratio smaller in reduced tillage. Soil hardness and three phase of soil between plants showed no differences between reduced tillage and normal tillage. 2. Soil water in response to making the tillage varied in soil layers of plowed soil and the growth stages. In the upper layer (0-5 cm) of reduced tillage, water ratio of soil was larger in early growth stage, and smaller in the lower layer (20-25 cm). 3. The growth was more vigorus in normal tillage than in reduced one. In the early stage, the growth of conventional cultivation was inferior, being planted 10 days after. But later, its growth was almost the same as that of the reduced tillage. 4. Root weight of normal tillage was the largest among three treatments and it was slightly larger in conventional cultivation than in reduced tillage. It seems to be clear that the tillage is useful to promote the growth of sugar beet. 5. Sugar content of reduced tillage was the largest among three treatments. Its available sugar yield was slightly larger than that of the conventional cultivation, because the ratio of harmful N and Na in the reduced tillage were smaller.

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This study was conducted to investigate the localization of tannin in the roots and seeds of buckwheat. Tannin was histochemically detected by the treatment of ferric chloride solution. Results were summarized as follows : 1. Tannin was detected in the stele of seminal root at the early growth stage as 11th day after sowing (Figs. 1 and 2). 2. The content of tannin decreased in the stele and increased in the cortex of lateral roots at the 18th day after sowing (Fig. 3). After 27 days, tannin mostly accumulated in the (cortex (Fig. 4). 3. Tannin accumulation in the cortex reached to maximum in lateral roots at the 33th day after sowing (Fig. 5). 4. Tannin was detected also in cortex of brace root and fine fibrous root (Figs. 6, 7, 8 and 9). 5. Coloration of tannin was also detected in immature seeds in the same lebel as in mature ones, but the sensitivity to detect tannin decreased by FAA fixation (Figs. 10A and 10B). 6. In mature seeds, tannin was localized in their outer seed coats, and tannin was first detected in brown seed coats at the bottom of the immature ones (Figs. 11 and 12). 7. Tannin was distributed within their pigment layers in the immature pericarp and within the inside parenchyma of the mature one, which corresponds to pigment layers of immature one (Figs. 13 and 14). 8. High content of tannin was detected in their basal parts of calyx in which the tannin was distributed in the epidermis of their adaxial side (Figs. 15 and 16).

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Influences of root pruning treatment on shoot and root growth were examined, using young tea plants (Camellia sinensis (L.) O. Kunsze cv. Yabukita). Morphological and functional properties of new roots (white root) were investigated from December to the following July, using 4-year-old plants treated in late August. Relationship between root growth and yield, and root pruning were studied by the different methods (5 times and intensities) of root pruning. High aged and thick roots generated numerous white roots after decapitated by root pruning (Table 1.). The white roots grew more thickly and long than these on intact roots in the control plot, showing poor curvature and branching (Fig. 2). The white roots showed a high level of the activity by TTC reduction and uptake rate of nitrogen during winter season. But, thereafter, their both functions steeply lowered during the first crop season, so that fell below the similar roots in control plot in the successive summer crop season (Figs. 3, 4). The white root, however, maintained the activity of apex and respiratory rate that exceeded the similar roots in the control plot over the whole experimental period (Figs. 3, 5). This suggests that the deterioration in their some functions during and after the first crop season partially attributes to morphological properties, namely, poor branching and so on. The root pruning caused a decrease in lignified root despite treatment times (Jul. to Nov.) but induced 10-40% increase in white roots except the treatment in late November, so that percentage of the white root to total root weight rose by 10-20% relatively to the control plot (Fig. 6, Table 3). The most excellent regeneration of roots was observed in 40-60% root pruning plots (Fig. 7). In the first crop season after root pruning, total shoot weight per plant compared poorly with the control plot regardless of treatment times (Table 4). From the results above, appreciate root pruning was concluded to be effective to induce active growth of roots and to rejuvenate root system. Crop productivity has been also estimated to annually rise with development of the rejuvenated root system although that considerably decreased in the first year following to root pruning treatment.

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This study was conducted to determine the effects of soil water deficit on the seed yield and the yield components of safflower plants. Four plants were grown in a 1/200O a Wagner pot containing soil, chemical fertilizer and compost. Ample amount of water was supplied before the completion of differentiation of an lateral buds (May 27). After this stage, water was supplied to reach a level of 90%, 60% or 40% of the maximum water-holding capacity of the soil, twice a day. The results obtained were as follows. 1. Water deficit treatments inhibited the internode elongation of the main stem, resulting in a short main stem, and inhibited strongly the growth of lateral buds at the lower nodes (Table 1). 2. The number of leaves, number of bracts and total number of leaves and bracts in the main stem were not affected by soil water deficit. In the uppermost branch, reduction in the soil water content did not affect the total number of leaves and bracts, but the number of leaves decreased, though not significantly, and the number of bracts increased in the 40% plot (Table 2). 3. Soil water deficit decreased significantly the mean area of leaf and bract and the total area of leaves and bracts of the plant (Table 3). 4. Soil water deficit at a level of 40% of the maximum water-holding capacity of the soil delayed the flowering of the heads of the uppermost branches, while no effects were observed on the flowering of the head of the main stem (Table 4). 5. The number of seeds and seed yield (dry weight) per plant were considerably decreased by soil water deficit, whereas the number of florets, percentage of ripened seeds, number of seeds and seed dry weight per head were not affected (Table 6). It was evident that the decrease in seed yield per plant was caused by the decrease in the number of heads per plant, which resulted from the decrease in the number of branches. It was also shown that water deficit inhibited more strongly the development of branches, leaves and bracts than the ripening of the seeds (Table 5).

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[in Japanese]

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This experiment was carried out to define the effect of nitrogen fertilization at the different growth stages on the long stem yield of mat rush. For that purpose, watercultured mat rushes, cv. Asanagi, were treated to grow under the low (20 ppm N), the medium (60 ppm N) and the high (180 ppm N) nitrogen levels of culture solution at the early tillering stage (stage II), the tillering stage of the long stem (stage III) and then the elongating stage of the long stem (stage IV), respectively. The results are summarized as follows : 1. Number of tillers and the long stem (>105 cm) per hill at the harvest time increased under the high or the medium N levels for stage II and stage IV. On the contrary, for stage III, i.e. the middle growing stage which was defined as the tillering stage of the long stem, number of the long stem per hill increased under the low N level. 2. Moreover, it was found that the nodal position of the long stems on the stolons were changed and lowered basipetally under the low N level at stage III and the mean dry weight of the long stems was also increased by that treatment. 3. The utilization efficiency of the applied nitrogen during whole growth period of mat rush was estimated on the basis of the dry matter weight and nitrogen content of each part and it was found as low as about 50%. The result of this experiment suggested that 1) at the early tillering stage and the elongating stage of the long stem, the sufficient amout of nitrogen fertilizer should be topdressed to promote the early tillering and the long stem elongation but 2) at the tillering stage of the long stem, the smaller amount of nitrogen fertilizer shoud be applied for getting higher yield of mat rush.

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In the previous papers, the authors have reported on the compositions of C₃ and C₄ species in the grass flora of Japan, and also in subtropical and tropical regions of South East Asia, in which we attempted to clarify the geographical distribution of C₃ and C₄ species with special reference to climatic conditions and altitudinal cline of the grass flora of tropical South East Asia and discussed its ecological significance. In the present study, the geographical distribution of C₃ and C₄ species in the grass flora of Indian subcontinent was critically investigated in relation to the climatic conditions. The results obtained are as follows : 1) A highly negative correlation exists between the percent of C₄ grasses and annual rainfall in each subdivisional region in Indian subcontinent. In dry regions, however, a predominant occurrence of C₄ grasses was noted, often attaining 100%. 2) Due to a relative increase of the Festucoideae grasses in the regions of Northwest-, North- and Himal-India, there occurs no conspicuous relationship between the percent of C₄ grasses and annual rainfall. However, disregarding the Festucoideae, we can recognize a theoretically expected trend between the relative abundance of C₄ grasses and annual rain fall. 3) The relative abundance of the species belonging to Eragrostoideae increases with decreasing annual rainfall, and/or declines drastically with increasing rainfall. Under the wet conditions with more than 1200 mm annual rainfall, the percent of Eragrostoideae species decreases to a certain low level, ca. 20%. 4) The percent of Aristida species increases with decreasing annual rainfall, and/or declines drastically with increasing rainfall. The highest subdivisional percent of Aristida species can be recognized in the Indian-desert (ca. 10%), but the lowest in the regions of South India, Ceylon and East India (ca. 1%). 5) The percent of the Panicoideae increases in response to the increase in annual rainfall with favourable temperature regime, but seems to attain a saturated level under the conditions with more than 1200 mm annual rainfall. 6) The relative abundance of C₃ species belonging to the subfamily Bambusoideae, Oryzoideae and Arundionoideae is correlated most highly with annual rainfall. 7) The relative abundance of C₄ grasses in the grass flora of a certain region is determined directly by the number of C₄ species present in that region under consideration, but also indirectly by the number of total C₃ species present there.

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Using 58 bulu and 54 tjereh rice cultivars of Indonesia, relationship among degree of grain shedding, histological peculiality of abscission region and esterase zymogram were investigated. The results obtained were summarised as follows. 1. The breaking tensile strength of a variety varied from 86 to 249 g in bulu type rice and from 51 to 220 g in tjereh type rice, the average being 180±36 g in the former and 107±41 g in the latter. The strength of 39 out of 57 cultivars in the bulu type rice (68.4%) was larger than 171 g, while the strength of 44 out of 50 cultivars in the tjereh type rice (88.0%) was smaller than 170 g. Especially, the strength of about two-thirds in the latter was smaller than 110 g (Table 1). 2. Both of bulu and tjereh type rices, excepting one cultivar in the former and two cultivars in the latter, had abscission layer. In most tjereh type rice cultivars (90.0%), parenchymatous cells in the abscission layer cracked completely at harvest time, whereas no cracking occurred at the harvest time in most bulu type rice cultivars (93.0%) (Table 2). 3. As to the esterase isozymes, four genotypes of 1 (Est₁ Est₂^S Est₃^F), 3 (Est₁ Est₂^F Est₃^F), 6 (Est₁ Est₂^O Est₃^S) and 8 (Est₁^O Est₂^S Est₃^S) were found commonly in both bulu and tjereh type rices. Additionally, genotype 12 (Est₁^O Est₂^O Est₃^F) was found in the bulu type rice, while genotype 9 (Est₁^O Est₂^F Est₃^F) was found in the tjereh type rice. According to Nakagahra, the esterase genotype 1 corresponded well to the majority of Indian varieties (Indica), genotype 3 to that of southern China (Sinica), genotype 6 to that of the nothernmost areas (Japonica). Genotypes 8 and 12 are representatives of hill and mountain rice in Southeast Asia (Javanica). In the bulu type rice, the proportion of cultivars belonging to the genotypes of 6, 8, 12, 1 and 3 was 79.3%, 10.3%, 6.9%, 1.7% and 1.7%, respectively. In the tjereh type rice, on the other hand, the number of cultivars to genotypes of 3, 1, 6, 8 and 9 was 43.8%, 39.6%, 8.3%, 6.3% and 2.1%, respectively (Table 3). 4. In the bulu type rice, number of cultivars having "hardly shedding-uncracking abscission layer- Est₁ Est₂^O Est₃^S" was largest (78.9%), and next was those having "hardly shedding-uncracking abscission layer-Est₁^O Est₂^S Est₃^S" (7.0%). In the tjereh type rice, the proportion of cultivars having" easily shedding - cracking abscission layer - Est₁ Est₂^F Est₃^F" and those having "easily shedding - cracking abscission layer - Est₁ Est₂^S Est₃^F" was 41.9% and 39.5%, respectively (Table 4). Judging on these three characteristics, bulu type rice was similar to Japonica type rice.

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We produced a new core-sampler and an auxiliary soil-cutting implement in order to study more efficiently and exactly the situation of rice root system in paddy fields. And we evaluated the research method statistically in a paddy field of Saga University. The core-sampler and the soil-cutting implement were characterized by smallness, lightness and simplicity. 1. The core-sampler (Fig. 1-1) consists of three parts, that is, an outside cylinder of steel, an inside cylinder of hard vinyl (Fig. 1-3) and a cap of steel (Fig. 1-2). The outside cylinder is 250 mm in length, 93 mm in inner diameter and 4 mm in thickness. The bottom edge of the outside cylinder is sharpened in order to make it easy for the cylinder to penetrate the soil. The inside cylinder, vertically cut into two halves and then connected with tapes, is set in the outside cylinder. 2. When we research the root system in the paddy field, we first drive the core-sampler into the field by striking the cap with a hammer to a depth of 15 cm, which makes it possible to get most of the roots. Second, the soil-cutting implement is inserted into soil along the outer was of the outside cylinder down to the check point, then the handle of the sticker is horizontally turned round to cut of the core-sampler from soil layer (Fig 2). Finally, the core-sampler is pulled up from the field by holding the grips with both hands, then soil cores are taken out of the inside cylinder and washed with running water. 3. Three young rice seedlings (var. Reiho) were planted in each hill spaced 21.5×21.5 cm on 11 June 1981. The rice plants were grown under a standard cultivation system popular in Saga Prefecture. Sampling the roots was carried out at heading time. 4. Sampling posittions of the soil cores are shown in Fig. 4: positon A is just on a hill, B is between two hills and C is the center of four hills. 5. Whole roots of a single hill were sampled by a square monolith sampler sized 21.5×21.5×15.0 cm, the volume of which was equivalent to the roots growing in the sphere of a single hill as shown in Fig. 3. The root amount obtained by the monolith was taken as a standard value in estimating the amount of roots by using the core-sampler (Table 1). 6. If we estimate the whole root weight in an unit area within a limit of 10% error statistically, nine samplings by the square monolith are required. In the case of positions A and B, fifty six and sixty nine samplings are necessary, respectively (Table 1 and Fig. 5). The number of samplings is so large that the core-sampling method may be considered unsuitable for the estimation of root weight. 7. Position C is the best for the survey of the root distribution in different soil layers because twenty four samplings are required within a limit statistic error of 10%, but within a 20% error only seven samplings are required (Table 1, Table 2). 8. As the root weight is greatly influenced by the depth of plow layer, we need to examine beforehand the plow layer depth of the paddy field. 9. Judging from the results, newly developed core-sampler and the soil cutter, especially the latter, proved to be very useful and convenient tools for the investigation on the root system of rice plants in a paddy field.

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[in Japanese]

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The second and fourth nodes from the top of rice culm were harvested at the times of flag leaf emergence and heading respectively. Ultrastructural observation has been made on the elliptical and diffuse bundles in particular reference to solute movement in the node. 1. In the phloem of elliptical bundles, which are continuous with the large bundles of leaf, both the sieve elements and phloem parenchyma cells increased in number and showed a ratio of about one to two. A sieve element was connected by plasmodesmata with the plural number of phloem parenchyma cells (Fig. 1). In the border region between phloem and xylem, the parenchyma cells with dense cytoplasm were interconnected by plasmodesmata (Fig. 2). It is assumed that the solutes actively move in the symplast between phloem and xylem. 2. The elliptical bundles contain numerous xylem transfer cells, in which the wall ingrowths were formed on the walls contacting with tracheary elements. The mitochondria with developed cristae and the plastids with peripheral reticulums were contained in the xylem transfer cells (Figs. 3 and 4). A large amount of plasmodesmata was found in the walls between xylem transfer cells and bundle sheath cells, between bundle sheath cells and fundamental parenchyma cells and also between fundamental parenchyma cells (Figs. 4, 5, 6 and 7). It can be (considered that the solutes absorbed from transpiration stream by xylem transfer cells are transferred actively to fundamental parenchyma via bundle sheath cells. 3. In the phloem of diffuse bundles which are surrounding the elliptical bundles and are continuous with the large bundles of internode, the number of sieve elements was about 3.5 times as many as phloem parenchyma cells and the sieve elements were partitioned by numerous sieve plates (Fig. 8). The phloem parenchyma cells of diffuse bundle contained abundant mitochondria, plastids, rough endoplasmic reticulum and ribosomes (Figs. 9 and 10). It is suggested that the phloem parenchyma cells play an important role in climbing of photosynthate in the phloem of diffuse bundle through energy supply.

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[in Japanese]

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[in Japanese]

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