Growing the rice plants under each condition of some possible combinations of the daytime air-temperatures (A_D: 26, 20 and 14°C), the daytime water-temperatures (W_D: 26, 20 and 14°C), the nocturnal air-temperatures (A_N: 20, 14 and 8°C), the nocturnal water-temperatures (W_N:20, 14 and 8°C) and the number of days of treatment (P: 3, 6 and 9 days) at each stage of growth, the autliors examined their main effects and interactions on the percentage of sterile grains. The daytime was settled for eight hours from 9.00 a.m. to 5.00 p.m. and the night-time was settled for sixteen hours from 5.00 p.m. to 9.00 a.m. of the following day. The depth of water was kept in four cm. above the soil surface in pots. The experimental design was 3⁵ factorial in 81 units (1/3 replicate) with one block and defining contrasts 1=A_DW_DA_NW_N²P. The results were summarized as follows; 1. At the differentiating stage of first bract primordia (T₃), all the main effects and their two-factor interactions were not significant (table 4). 2. At the middle differentiating stage of primary branch primordia (T₄), only the main effect of A_D was significant at 5% level. However, that was not considered to be important because the differences of the percentage of sterile grains among them were smaller than 3%(tables 3 and 4). 3. At the stage of reduction division of pollen mother cells (T₅), the main effects of A_D, A_N and P and all of their two-factor interactions were significant at 0.1 or 1% levels. Moreover, the effects of W_D, W_D × A_N and W_D × W_N were also significant at 5% level. The contour lines of each pefcentage of sterile grains based on A_D and A_N were straight and parallel with the line of mean air temperature for three day treatment (fig. la). On the other hand, the contour lines for six and nine day treatments were curve together (fig. 1b-c). 4. At the head emergernce stage (T₆), the effects of A_D, A_N, P, and A_N × P and A_N × P were significant at 0.1% level. However, for three day treatment, A_D and A_N didn't affect the percentage of sterile grains. For six and nine day treatment, A_D and A_N were effective and their contour lines of each percentage of sterile grains were curve (fig. 2b-c). 5. The optimum ranges between A_D and A_N to minimize the percentage of sterile grains for each mean air-temperature were found in all the cases in which the contour lines were curve. The lower the mean air-temperature became, the bigger the optimum range between A_D and A_N became in most cases. Moreover, the optimum combinations of A_D and A_N to minimize the percentage of sterile grains were found to be about 24-20°C in all cases (fig. 1∼2).

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Acid soluble nucleotides of wheat were surveyed at the one month after heading. They were extracted with cold perchloric acid and separated by chromatography on columns of Dowex 1(C1-), followed by repeated paper chromatography. The nucleotide compostition of wheat is presented in table 5. The detected nucleotides in the grain were adenosine monophosphate (AMP), adenosine diphosphate (ADP), ADP-glucose, ADP-X₁, ADP-X₃, adenosine triphosphate (ATP), uridine monophoshate (UMP), uridine diphosphate (UDP), UDP-glucose, UDP-X₃, uridine triphosphate (UTP), cytidine monophosphate (CMP) and guanosine derivatives. In leaves and culms, only AMP and ADP were detected. The total nucleotides were 12.39 μmoles in 75 g fresh weight of grains, while 0.35 μmoles in the leaves and culms. Thus, the contents of nucleotides in leaves and culms were approximately 3% of those in grains. ATP and ADP-sugar were not detected in leaves and culms. These nucleotides were probably decomposed to AMP and ADP during senescence. In grains, ADP- and UDP- sugars were main derivatives of adenosirle and uridine. ADP-sugar and UDP-sugar occupied 54% and 58% of respective nucleotides. As reported in the previous paper, rice contained UDP-glucose in the leaves and culms at the stage of one month after flowering, but wheat did not as described above. These differences may reflect that leaves and culms of rice are less senescent than those of wheat at this stage. Wheat, whose ears were cut off at the flowering stage, were grown further one month. The detected nucleotides from leaves arLd culms of these treated plants were AMP, ADP, ATP, UMP, UDP, UDP-glucose, UDP-X₃ and CMP. ADP-sugar and UTP which were detected in non-treated plants were not found in treated plants. The contents of nucleotides in treated plants were about 20% of those from the non-treated plants. Only AMP was greater in treated plants than in non-treated. Adenosine derivatives were predominant in treated plants. The treated plants contained less UDP-glucose and more AMP in their acid soluble nucleotide pool than non-treated plants. When ears were cut off, leaves and culms were probably substituted for ears to pool acid soluble nucleotides. Identification of the nucleotide sugar of fraction f, j and I (see figure 1) was tried. After mild hydrolysis with 20% acetic acid, several sugars were detected on paper chromatogram (see figure 3). Glucose (X₂), maltose (X₃) and fructose (X₁) were tentatively identified after comparison with R_f values (R_glucose values) of authentic samples.

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Anatomical observations were made among seedling leaves of cereal crops. The crops used in this observation were classified systematically to the following three groups. Bambusoid group····rice (Oryza sativa and Oryza glaberrima), Panicoid group····Italian millet (Sataria italica), common millet (Panicum Crus-galli), grain sorghum (Andropogon sorghum) and maize (Zea mays) and Festucoid group····rye (Secale cereale), barley (Hordeum vulgare), wheat (Triticum vulgare) and oats (Avena sativa). In these crops, most of the mesophyll cells were so-called the arm-cells having several protuberances. According to the direction of cell elongation and protuberance development, the mesophyll cells of cereal leaves were divided into the following types: tubular palisade cells (P-type), longitudinally elongated arm-palisade cells (LP-type), transversely elongated arm-palisade cells (TP-type) and rachymorphous arm-cells (R-type). The TP- type cells were found only in the rice species, whereas the other types were found in the almost every crop of the panicoid and festucoid groups. The P- and LP-type sells occur in the outer layer of the mesophyll and the R-type cells occur in the inner layer of the mesophyll. There were large differences among these crops in size of the mesophyll cells. The size becomes larger in the order, bambusoid, panicoid, festucoid. Size of the mesophyll cells was positively correlated to thickness of the mesophyll and length of the epidermal cells, whereas the number of stomata per unit leaf area was found to be negativbly correlated. In the leaves of the rice species, palisade-like arrangement of TP-type cells was observed in longitudinal sections. In the leaves of the panicoid and festucoid groups, palisade-like arrangement of LP-type cells was observed in transections. Orientation of the long axes of palisade cells, appearing in transections, were closely related to their position in the mesophyll. In the outer layer of the mesophyll, the palisade cells were oriented with their long exes at right angles to the leaf surface. The palisade cells around the vascular bundles were oriented in a radiating manner. Panicoid leaves having short interveinal distance and well-developed parenchymatic bundle-sheath, showed a distinct radial arrangement of the mesophyll cells. From this observation, the relationship between function and structure of the mesophyll was discussed.

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Plants of different types of rice varieties, Sasanishiki and Kamenoo, were grown in pots with different levels of nitrogen, and the mesophyll structural changes of leaves were observed. In Kamenoo, the typical panicle weight type, the ratio of the mesophyll surface area to the leaf area (MS/LA) and the number of protuberances developed by each mesophyll cell were decreased by application of nitrogen. In Sasanishiki, the typical panicle number type, these structural changes of the mesophyll were not so remarkable as those in Kamenoo. In longitudinal sections of both varieties, the intercellular spaces area in the mesophyll was increased in proportion to the amount of applied nitrogen. So far as the unit leaf area was concerned, the number of mesophyll cells was decreased by application of nitrogen. Flowever, the total cell surface area was hardly reduced because of increase in surface area of each mesophyll cell, and this trend was more evident in Sasanishiki than in Kamenoo. From the results of this experiment, it was suggested that the application of nitrogen might bring about a favourable structure for gaseous diffusion in the mesophyll.

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In order to study photosynthesis, respiration and water metabolism of the crop, it is necessary to know the behaviour of stomata which are the major gateway for transpiration and gas exchange. The available methods of stomatal aperture measurement are divided into three groups, that is, (1) microscopic technique; (2) infiltration method; and (3) porometler method, each of which has its own advantages and shortcomings. Among these methods, porometer which can measure continuously variable stomatal resistance is more suitable for the metabolic study of the crop than other methods which measure the actual size of stomatal aperture. It was indicated by Heath and Williams, however, that in the porometer method the stomata inside the permanently attached cup open much more widely than the stomata outside the cup. This wide opening of stomata inside the cup might be caused by CO₂ deficiency due to photosynthesis in the mesophyll within the cup. And they pointed out that such a type of recording porometer is unfit for use because of the danger of misleading the experilmental results. The present paper gives a description of a newly devised recording porometer with an attachable cup which enables continuous recording. The results of some tests by this instrument are also presented. 1. The new recording porometer is composed of clear plastic cup (0.44 cm²), mercury manometer with three electrodes, electric valve which closes silicone tube, membrane air pump and event recoder (figs.1 & 2). 2. The cup was cemented absolutely airtight with the birdlime on the lower epidermis of the leaf of the tobacco plant. No injury was detected in the leaf tissue for a long period, though leaf blade had a great number of hairs and did not show any toughness. 3. The air pressure in the porometer is constantly kept average 15mm mercury higher than the atmospheric pressure. Consequently, the air included in the porometer escapes away to the atmosphere through the stomata inside the cup (fig. 1). The mercury within manometer gradually falls to the previously decided state (P₁) according to the exhausting of the air, and then the electric valve is open and mercury is restored up to the former state (P₂) by the fresh air from the membrane air pump. The movement of the electric valve is automatically repeated by the direction of mercury, and each stroke of mercury accompanied with electric valve (M₁) is continuously recorded on the event recorder (fig. 3). 4. Stomatal viscous flow conductance in the tobacco leaf was indicated 25∼45 cc/min in the daytime which was obtained by the new recording porometer (fig. 4). This rate of viscous air flow in the porometer was 8∼15 times as much as that of the air including sufficient CO₂ for the photosynthesis of the mesophyll inside the cup. 5. A highly significant correlation (r=0.924, significant at 0.1% level) was obtained between porometer conductances inside the cup and infiltration scores outside the cup (fig. 5). 6. The facts mentioned above (4, 5) show that no CO₂ deficiency occurred in the attachable cup of the new recording porometer, and that similar stomatal movement was detected at the both sides of the cup. Accordingly, it can be said that the defect of porometer of old type, such as indicated by Heath and Wrilliams, has been completely removed. 7. The relation between porometer conductance (x) and the mean of stomatal aperture width (y) in the lower epidermis of the tobacco leaf was given by the equation of logarithm function :y=2.258+3.066 log x. A highly significant index of correlation (r_c=0.926, significant at 0.1% level) was obtained between conductances and stomatal apertures. Consequently, it will be able to estimate the stomatal apertures in the leaf by the porometer conductances (fig. 7). 8. [the rest omitted]

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In order to bring about improvements in the photosynthetic ability per unit leaf area of soybean varieties by means of breeding techniques, it is desirable to clarify the genetic characteristics of photosynthetic ability of soybeans and to establish the simplified method for soybean selection. So, we tested the differences in the photosynthesis among F₃ lines by using "Manshu×Harosoy" and "Norin-1×Harosoy" as samples. The results are summarized as follows : 1. A significant difference was found statistically in the net photosynthetic rate at saturated light intensity amomg F₃ lines in either case of the two crosses. 2. Correlation coefncients of F₃ progeny(mean value of respective lines) to F₂ single plants for two crosses were high for leaf thickness and fresh leaf weight per unit leaf area, but low for net photosynthesis and total N content per unit leaf area. 3. But, the majority of F₃ lines higher in photosynthetic ability were obtained from F₂ plants with higher photosynthetic ability, and vice versa, F₃ lines lower photosyntllesis were mostly derived from F₂ plants with lower photosynthetic ability. Thus the effect of the selection on the increse in photosynthetic ability was proved. 4. In the case of lines higher in photosynthesis, a saturated light intensity being higher, it was recognized that under the condition of high light intensity, the efficiency of light energy utilization can be increased. 5. Most of F₃ lines higher in photosynthetic ability showed a tendency to become higher in the total N content per unit area, in leaf thickness and in the fresh leaf weight per area. This fact can be taken up as a means of the soybean selection. techniques.

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1. The rates of vegetative growth of the non-tuberous roots of sweet potatoes were tested according to various soil treatments in the later growth stage of sweet potatoes. Such test proved that no appreciably great effect was found in the prodution of dry matter (total dry weight), while a striking effect was found in the distribution of dry matter. 2. Namely, according to the increase of non- tuberous roots it showed increase in the weight of tops, while decrease in the weight of tuberous roots, thus the ratio of tuberous root weight to the total dry weight became lower (correlation coefficient : r=-0.891**). And a high positive correlation was also found between the ratio of tuberous root weight to non-tuberous root weight and the ratio of tuberous root weight to total dry weight (r=+0.952**). This fact made clear that for the purpose of keeping the ratio between tuberous root weight and total dry weight at the rate of 40 per cent or higher, the ratio between tuberous root weight and non-tuberous root weight should to be kept at the rate of 1O times or higher. 3. It was also found that high in ground temperattlre, much in soil moisture and low in the concentration of oxygen are soil conditions for acceleration of the growth of non-tuberous roots as well as of the excessive vegetable growth of sweet potatoes.

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Experiments were carried out to make clear the process of devernalization of winter wheat, variety Norin No. 27. (1) The plants vernalized immediately after sowing for 30 or 40 days at 1°, 4°, 8°, 11°, and 15°C, respectively, were exposed to relatively high temperature of 12°, 18°, or 24°C for l0 days. The vernalization effect achieved at 1°C or 4°C were reversed markedly by the subsequent exposure to high temperature such as 18°C or 24°C. The effect obtained at 8°C or 11°C, on the other hand, were reversed a little by the same treatment. (2) The plants vernalized immediately after sowing at 1°C for 30 days were exposed to high temperature varying diurnally for 1 week. Among the plants which were exposed to various combinations of temperature being equal to mean temperature, the plants exposed to high temperature varying diurnally emerged the flag leaves on the same date as those exposed consecutively to a constant high temperature or emerged somewhat earlier than the latter. (3) The plants vernalized immediately after or 15 days after sowing at 2°C for 30 days were exposed to high temperature (25°C) under the light of different intensities. The vernalization effect was reversed markedly by the high temperature treatment under dark condition. This vernalization effect was reversed by the high temperature treatment more markedly under high light intensity than under low light intensity.

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Milk vetch and Italian ryegrass were cultivated in water solutions with different composition. Roots of these plants were successively extracted with 66% EtOH (Fr.1), cold water (Fr.2), O.1M acetic acid in 75% EtOH (Fr.3), 0.3% NaOH in 60% EtOH(Fr.4), 1N〓NaC1(Fr.5), 2% acetic acid (Fr.6) and with 5% HC1 (Fr.7). The residual material was ashed (Fr.8)and Ca and Mg in these fractions were determined, The results obtained were as follows : 1. When the concentration of Ca in culture solution was strongly lowered from the standard concentration, the concentration of Ca in each fraction decreased slightly indicating that the rate of Ca transport to top was reduced. At very high Ca concentration in culture solution, calcium carbonate and Ca bound to pectic acid besides water soluble Ca greatly increased. First two Ca fractions probably came from the excess Ca, being absorbed more than the amoun to be transported to the top in a short period. Italian ryegrass, which required lower Ca concentration fo culture solution for optimum plant growth, was cultivated at standard Ca concentration and low Ca concentration. The two largest Ca types of the root, Ca bound to pectic acid and tribasic calcium phosphate, were smaller in amount and on the other hand the reactive Ca soluble in alcohol was high. This pattern of distribution of Ca appeared to explain the less repuirement of Ca in root and the more translocation fo Ca to the top by this plant. In Italian ryegrass, whose plant growth was not suppressed too much at low Ca concentration, the amount in the root of calcium carbonate and Ca bound to pectic acid were reduced but no reduction was observed in both types of transportable Ca, soluble in alcohol and in water. This may be attributed to the effective transport of Ca to the top at low Ca solution. At excess Ca concentration in culture solution, Ca bound to pectic acid and especially tribasic calcium phosphate accumulated markedly in root. 2. The Ca bound to pectic acid and protein were directly depressed by increase of Mg concentration in solution caused by the competitive effect of Mg. The amount of tribasic calcium phosphate was not affected by direct competitive effect of Mg but was depressed by the decrease of concentration ot Ca in root. When the concentration of Mg in culture solution was so increased as to reduce Ca bound to pectic acid and tribasic calctum phosphate by the competitive effect of Mg, the plant growth was reduced. 3. At low Al concentration of 0.5ppm in culture solution, the binding of Ca to protein and pectic acid and accumulation as tribasic calcium phosphate were inhibited. At high Al concentration of 5ppm, accumulation of calcium carbonate was also inhibited besides the last two types. In Italian ryegrass, which was tolerant to Al toxicity, the depression of Ca in above three types at the Al concentration of 0.5-5ppm in culture solution was little. 4. At low pH solution of 4.3 in culture solution, alcohol soluble Ca in root was depressed as compared with that of pH 5.3 and resulted in the depression of translocated Ca at the top. And the accumulation of tribasic calcium phosphate in root was also inhibited in this case. In milk vetch, which was susceptible to the injury of high H ion, the amount of Ca bound to pectic acid in root also decreased as well as the above two types of Ca, at low pH of solution. At high pH value of 6.3 in culture solution, Ca concentration of tribasic calcium phosphate and Ca bound to pectic acid increased as compared with that of pH 5.3. 5. The concentration of Mg fractiond, which were bound to pectic acid, soluble in alcohol and soluble in alcohol with acetic acid, increased with increase of Mg concentration in culture solution. In milk vetch, whose growth was severely reduced by excessive Mg concentration in culture solution, the concentration of Mg in above three types easily increased at Mg concentration of 2-15ppm in solution. [the rest omitted]

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減数分裂期に冷温処理を行ない,頴花,葯および花粉の発育経過をしらべた. これらの形質の生長速度は処理期間中いちじるしく抑制されたが, 処理終了後は正常なものと同じ速度に回復した。正常なものも処理されたものも減数分裂初期から小胞子の第2収縮期までは, 頴花長によつて花粉の発育時期を推定することができる. 冷温感受性のもつとも高い時期を正確に判定するため, 冷温処理時に1cmごとに葉耳間長の印をつけ, 処理時の花粉の発育時期と稔実歩合との関係を, 葉耳間長別, 穂の最先端5頴花の位置別にしらべた. 冷温感受性のもつともたかい時期は,これまでいわれてきた減数分裂盛期ではなく, 4分子期から第1収縮期までの小胞子初期である.

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冷温にたいしてもつとも感受性のたかい小胞子初期ころのタペート細胞を電子顕微鏡により観察した. タペー卜細胞は細胞質が充実しており,おおきな液胞をもたない. 粗面小胞体が減数分裂のおわりごろから発達しはじめ, 小胞子初期にほおおきなかたまりになる. タペート細胞間の細胞壁は非常にうすく, ほとんど細胞膜のみからなつている. 莉腔側の細胞壁ほカロースで‘できており,のちにカロースがとけて細胞膜が露出する. 新生小胞子期にこのカロース壁の下に球状体が生じ, カロース壁がとけさると球状体も露出する. そのご電子密度のたかい突起が, この球状体の表面に生長していく. 以上のような形態的特長は, タペート細胞の分泌的性質およびまもなくこわれていく運命とよく符合している.

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小胞子初期ころに冷温処理をおこなつてタペート肥大をおこさせ,それを電子顕微鏡により観察した. 肥大細胞は(横断切片の面において)数個のもとのタペート細胞が融合してできたもので, 核ほ萎縮変形し,小胞体は膨潤し,やぶれた細胞壁(および細胞膜)は痕跡として観察された.その他の細胞要素は形態的に正常であつたが,肥大にともなつて相当に増殖していた.

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The interrelationships of aerial parts and root characteristics in varieties of different plant types in rice plant were studied with respect to yleld components, leaf senescence, and the angle of leaf inclination. The results obtained were as follows : (1) Among 16 early duration varieties of different types, there was highly significant correlation between the number of panicles and the weight of upper nodal roots. While, there was a close correlation between the weight of lower nodal roots and the weight of panicle, which was negatively correlated with the number of panicles. (2) During the ripening stage, a close correlation was found between the activity of upper nodal roots and the degree of drooping of leaves in early duratioll varieties. However, similar data collected from late duratioll varieties did not show a clear correlation between the two characteristics. (3) A close correlation was found between root activity and chlorophyll content of leaves, leaf senescence in early duration varieties at their ripening stage. The same result was obtained with late duration varieties. (4) Among late duration varieties, close correlation was found between root activity at the ripening stage and grain yield.

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In a previous paper it was shown that the characters and activities of roots were closely related to the charecteristics of aerial parts with varieties of different plant type. The present paper is concerned with using mutatel strains derived from Norin 8 the relationships of root characteristics to the number of panicles and the angle of leaf inclination. The results obtained were as follows. (1) The inclination of the flag leaf is closely related with the root activity. The higher the root activity, the larger the inclination of the flog leaf. (2) In general, the panicle-number-type varieties produced more upper nodal roots than the lower ones. The upper nodal roots, as a result, occupied the major portion of the total root weight but the roots were slender. The activity of the lower nodal roots was not so high as that of the upper ones. This might be, the reason why the panicle-number-type varieties showed faster senescence of the leaves. (3) On the other hand, the panicle-weight-type verieties produced thicker and more active lower nodal roots Which might be responsible for the later leaf senescence as compared with the panicle-number-type varieties.

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The object of this study was to know how the diameter of the first elongated internode and diameter of loots formed at each leaf-shoot unit are related to the number of spikelets per panicle of main culm and tillers in individual or group of varieties. The results of study were as follows : (1) A close positive correlation was found to exist between the number of spikelets per panicle, and the diameter of roots formed at the 3rd, 4th, 5th and 6th leaf-shoot units. (2) The positive correlation was recognized between the number of spikelets per panicle and the number and diameter of vascular-bundles in roots formed at the 3rd leaf-shot units. (3) It was detected that the number of spikelets per panicle was those positively and significantly correlated with the diameter of roots, especially formed at the 3rd leaf-shoot units, the diameter of the first elongated inter-node at the base of the culm and the diameter of neck-node. The same tendency was observed even among varieties or within tillers of one same hill.

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This study consists of two categories. In order to clarify the effect of elimination of nitrogen application at different growth stages on the degree of leaf senescence and the root activity, the first experiment was carried out under water culture conditions. The second one was aimed to investigate variation of characters and movement of mineral nutrients within one and the same hill after root systems of the plant were separated and exposed to two different environments. The results obtained were as follows. (1) The elimination of nitrogen application greatly affected the chlorophyll destruction of the excised leaf and reduced the root activity. (2) The elimination of nitrogen application resulted in a great retardation of the root activity both at the tillering stage and the stage of reduction division. The activity of the lower nodal roots were severely affected at the tillering stage while that of the upper nodal roots was mostly retarded after reduction division stage. (3) By dividing roots into two halves and exposing each one to different nitrogen leveles, it was found that tillers and their roots were closely related each other. It appeared that the roots distributed in a given root environment affected mainly the tillers connected with them. The movement of mineral nutrients among the tillers which connected different root systems within one and the same hill had being independent each others. (4) When different root environments were given to the plant, certain elements such as calcium, iron and manganese seeiried to be difficult to move from one tiller to another, while nitrogen, potassium, phosphorus and magnesium moved relatively easily each other.

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ダイズは開花期間が比較的長いため,開花期にもろいろいな発育段階の花を含んでいる. また,落花・落莢に対する補償作用もきわめて強い. これらの特性のため,低温処理の開始時期によつて, また年次によつて低温障害の程度が非常にちがうことがある.そこでこの実験では主茎の10節以上と分枝を摘除し,発育程度の同じ主茎花のみをのこして低温処埋(15℃)をして,開花期前後における, 1)低温の最も敏感な時期の決定, 2)低温処理期間の長短による障害の程度, 3)低温時の花間競合, 4)低温処理にともなう体内諸成分の変化などを明らかにしようとした. 開花期前後の低温はいずれも結莢率, 一株粒重を低下させるが, 開花期まで続く開花前の低温はとくに影響が大きい. 低温処理はその期間の長いものほど結莢率, 一株粒中を低下させるが,開花までの処理日数が15日以上になると, とくにいちじるしい. 低温処理によるこのような結莢率の低下は主茎葉数を5枚にして,花数をわずか3個に制限した場合にも認められるところから, 同化産物などの供給低下を背景に考えられる花間競合はほとんど考えられない. また乾物重,全糖,還元糖,全窒素,燐酸などの含有率は低温処理によって,著しく影響を受ける. とくに燐酸含有率の変化は低温処理で著しく増加し,ガラス質に戻すと減少する. しかしこれら成分と結莢率の低下との間の直接的な因果関係は追究されなかった.

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1. The line of phyllotaxis in main stem was as a rule parallel with the line of long dimension of grain, and the odd number's leaves grew on the opposite side of scutellum and the even number's leaves grew on thc side of scutellum. 2. When the third or fourth foliage leaves emerge, main stem begins to incline to right or left direction against the line of long dimension of grain, at the same time primary branch leaf arises on the opposite side. The divergence among main stem, first primary branch and second one was about 120 degrees each other. 3. When seeds were sown with embryos upward and on this side, the ratio numbers of plant in which primary branch developed the right side (type A) to those on the left side (type B) was nearly 1 : 1. 4. The ratio right handed plant to left ones in al1 leaves of main stem and branches was almost 1 : 1 too. Frequency of alternation of right handedness and left handedness was very high in the case of third or more upper leaves of main stem and branches. 5. The above mentioned tillering type A and B has a connection with right and left handedness of leaves in main stem. The plant which has a right-handed third and upper odd number's leaves forms type A, and left-handed one forms type B.

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Experiments were undertaken to investigate an injurious effects of sulfur dioxide and hydrogen fluoride in the atmospheres on stomatal apertures of tulip plants of flowering stage. Typical symptoms of injury caused by sulfur dioxide and hydrogen fluoride on tulip plants were observed during and after treatment. Stomatal measurements were made from silicone impressions. All fumigations with closed system were made in the same chamber. The results obtained were as follows: 1. Injuries by lOO ppm of sulfur dioxide and hydrogen fluoride were observed on leaf, floral axis and petal of tulip plant, especially whole leaves being severely damaged in the concentration. White color was a typical symptom of leaf injury caused by lOO ppm of these gases. A relative resistance in each part of the fumigated plant was in thc following order: floral axis > petal > leaf 2. Injuries at concentrations of 30 ppm and below of these gases were observed only on leaf. It was observed that tip and nlarginal part of leaf appeared by the injury with the change of color from green to white color by concentrations of 30ppm and below of sulfur dioxide and with the change of color from green to greyish brown color by concentrations of 30 ppm and below of hydrogen fluoride: and soon thc injured part was spread to the central part of the leaf with increasing concentration of toxic gases or the extension of treatment time. From the above-mentioned facts, we can macroscopically distinguish the injuries by sulfur dioxide from these by hydrogen fluoride by the difference in changed color of the injured parts. 3. In tulip plants, a signiftcant difference in the susceptibility was observed between the injury of sulfur dioxide and hydrogen fluoride. The susceptibility of leaf to sulfur dioxide was more sensitive than to hydrogen fluoride. 4. The symptoms of leaf injuries by spraying solution of hydrogen fluoride to tulip plant appeared by the change of color from green to greyish brown color, but not symptorn appeared by spraying solution of sulfur dioxide. 5. From the result of estimation of stomata number in the position and the portion of leaf, it was suggested that higher susceptibility of the leaf than that of the floral axis was due to greater number of stomata per unit area of the former. 6. The injury-symptom in a leaf developed gradually from the tip to the central and base portions. This fact may also be related to the greater number of stomata per unit area in the leaf tip, hence with higher content of sulfur absorbed, than the other portions of the leaf.

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