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SummaryThe effects of day-length and light intensity on the growth rate and leaf number of an early (Pink Ice) and a late (Orchid Rocket) flowering variety of Antirrhinum majus L. have been investigated. Growth rate, as determined by plant height or dry-weight increase, was greater for Pink Ice in all instances. When the two varieties were grown under similar conditions, the leaf numbers prior to flowering attained by Orchid Rocket were always greater than those of Pink Ice. With high light intensity the long-day (LD) responses of both varieties were characterized by leaf numbers which were on average 30 leaves less than the numbers found on plants grown in short days (SD) at high light intensity. Pink Ice exhibited this photoperiodic response to LD irrespective of whether the light intensity was high (26,000 lux) or low (6000 lux), whereas the leaf number of Orchid Rocket only declined in LD when the intensity was high. Plants of this variety grown in low light LD had leaf numbers similar to plants maint...

Summary Observations have been made relating to the effect of foliar and soil applications of Phosion (0.1 mg and 1.0 mg/ml in 0.01 % Tween 20) on the contents of nitrogen, phosphorus and carbohydrates in different parts of Abelmoschus esculentus plant during different developmental stages. Phosfon caused reduction in the stem length, and the leaf area, but increased the leaf number. The increase tn leaf number was probably due to the retention of the lower leves on stem for comparatively longer periods as a result of the treatment. The plants showed an increase in the levels of nitrogen and phosphorus during vegetative growth but their levels declined with the onset of flowering and fruiting. In fruits the nitrogen and phosphorus contents increased but the level of total carbohydrates fell in response to phosfon.

Three doubled haploid lines artificially derived from each of the burley tobacco varieties, Burley 21, Ky 10, and Harrow Velvet, were compared with the normal diploid lines in 1971. Some of the doubled haploid lines were gene-tically different from the normal diploid lines. At least, three out of the nine doubled hap-loid lines showed the reduced vigor, resulting in the lower yield than the normal diploids. However, none of the doubled haploid lines was higher than the normal diploids in yield. An experimental line, DH-6, derived from Ky 10 variety had an apparently higher leaf number than that of the parental variety. These results were ascertained by the experi-ments in the next year. From the comparison of clonally related doubled haploid lines, it was assumed that the genetic variation among the entries was due to the mutation occurred in haploid stage.

Differences in emergence, height, and leaf number between corn (Zea maysL.), soybean [Glycine max(L.) Merr.] and seven dicotyledonous weed species were measured until plants reached 15 cm in height or for 40 days, whichever occurred first, under several temperature regimes. Corn grew faster than the weeds at all temperatures. Initially soybean grew more rapidly than the weeds, but when they reached 15 cm in height the growth rate of weeds exceeded that of soybean. A positive and highly significant curvilinear relationship between plant height and leaf number was obtained for several temperature regimes for each species. Equations were derived for determining leaf number from plant height for each species.

The duration of the juvenile phase in early-flowering (Dorset Marl) and late-flowering (S123) red clover is described. Neither cultivar responded to inductive conditions at the first leaf stage but Dorset Marl attained maximum sensitivity by the 3-leaf stage. A comparable response was obtained with S123 only after the production of 12–13 leaves. The growth characteristics of the two types under continuous long or short days are described and possible explanations are advanced for the characteristic differences in tillering and stem internode number.

Controlled-environment facilities were used to examine the effects of temperature and photoperiod on tassel-initiation time, leaf number and rate of leaf initiation of two corn hybrids. The effect of diurnal temperature range on tassel-initiation time and leaf number was also investigated. There was a consistent decrease in time to tassel initiation as temperature was increased from 15° to 25°C regardless of photoperiod. There was no difference in tassel initiation time at 25° and 30°C under all photoperiods for both hybrids. Photoperiod increased the time to tassel initiation at all temperatures, however, the change in time was more pronounced at low temperature (15°C). Temperatures of 15, 20 and 25°C had little effect on changing the number of leaves. However, the 30°C-treatment resulted in an appreciable increase in leaf number over that of other temperature treatments. As photoperiod was extended, leaf number increased at all temperatures for both hybrids. Average leaf number increased by 2.1 for each hybrid by lengthening photoperiod from 10 to 20 h. The rate of leaf initiation was nearly doubled for United 108 and more than doubled for Guelph GX 122 when temperature was increased from 15° to 30°C. The two hybrids exhibited a pronounced difference in leaf-initiation rate at high temperature (30°C). There was a small change in the rate of leaf initialtion with photoperiod. It is concluded that the increase in leaf number with increasing photoperiod resulted from the prolongation of the time to tassel initiation. At low mean temperature (15°C), there was an appreciable delay in tassel-initiation time as the diurnal range was increased from 0.0 to 17.2°C. The delay at these ranges became smaller at the 20°C-mean temperature. At 25°C-mean temperature, there was a pronounced delay with an increase of range from 8.6 to 17.2°C. The number of leaves increased with mean temperature and diurnal range. However, the effect of temperature range became less pronounced at high mean temperature.

The number of inbreeding generations required to produce homozygotes may be reduced if the more homozygous individuals in each breeding generation are selected phenotypically in the segregating progenies for further inbreeding. To demonstrate this, inbred lines and their F1, S1, and S2 progenies were studied for number of days from planting to anthesis, plant height and total leaf number. The data indicated that a high degree of control of rate of inbreeding may be obtained by proper use of heterotic characteristics in selection. The technique is a simple one: the selection of those individuals in a segregating array that most closely approach the characteristics of the ultimate homozygotes obtainable from the population. If these traits are undefined, then simple negative selection for heterotic attributes should suffice. In an S1 progeny of maize, an individual with the same number of leaves and (1) as short as and (2) as slow to flower as the parental inbreds will be likely to be more homozygous than its taller and earlier flowering sibs of like leaf number. Since the inbreeder’s aim is not homozygosis per se but the development of agronomically useful homozygotes, the population dealt with should be sufficiently large to permit intense selection for outstanding individuals among the more homozygous members of each generation of selection.

1. Basswood seedlings were grown in sand and in solution culture in a chamber with a sealed atmosphere. Growth of plants receiving minus-sulfur nutrient solution was markedly limited. Those receiving complete nutrient grew vigorously. 2. Visual symptoms of sulfur deficiency included yellowed leaves, early death of the growing point leading to lesser stem height and leaf number at harvest, and a significantly low dry weight. 3. Other than smaller size, no visual symptoms of root damage were noted. 4. Top/root dry-weight ratios were appreciably smaller in the sulfur-deficient plants, showing the more marked effects of the deficiency on the tops. 5. Under certain environmental conditions the amount of sulfur supplied via the atmosphere may be sufficient for those plants having a low sulfur requirement.

SUMMARYHand-pollinated pods of the Crin Elite establishment cocoa progeny C77 X C23 showed that pod maturity, based on pod age, significantly affected bean viability as well as leaf area, leaf number, plant height and plant girth of the seedlings produced. Beans extracted from immature unripe cocoa pods only 15 weeks from hand-pollination were more than 50 per cent viable and produced seedlings vigorous enough for transplanting to the field after 20 weeks in the nursery compared with beans from 25-week-old normal, mature-ripe cocoa pods. Loss by black pod disease (Phytopthora palmivora Butl) could therefore be avoided and time of waiting for pods to attain normal maturity and ripening saved, by early harvesting.

Part I.-1. The growth of the photosynthetic area of Valencia orange trees has been determined from the total number and blade lengths of leaves from four trees of 3, 6, 12, and 29 years of age. The frequency curves were normal in the three youngest trees. 2. The physical characteristics of the four trees also were determined. 3. The relationships between tree age and mean blade area per tree, mean blade area per class per tree, mean blade fresh weight per tree, crown surface per tree, crown volume per tree, ratio of crown surface to crown volume per tree, trunk diameter per tree, total leaf area per tree, and total leaf number per tree can be expressed by an equation of the general type y = bxn, where x is time. 4. The relationships between tree height and crown diameter, crown surface, crown volume, ratio of crown surface to crown volume, trunk diameter, total leaf area, and total leaf number per tree can be expressed by the allometric equation y = bxk. 5. The relationships between dimensions of plant pa...

SummaryUnfeathered maiden trees of apple Stark Earliest (syn. Scarlet Pimpernel) were pruned back in winter to a height of 70 cm. The following spring five shoots were allowed to grow out, the others being removed. When the leading shoots were about 12 cm. long the trees were sprayed once with various concentrations of GA, TIBA, CCC and B.9 (see below), other trees being left unsprayed as controls. Subsequent effects on shoot growth were analysed in terms of leaf number and internode length. Apical dominance was destroyed or greatly reduced by GA (200 p.p.m.), TIBA (200 p.p.m.) and CCC (5,000 p.p.m.) and these substances all increased leaf number on the lower shoots. B.9 (2,000 p.p.m.) had no effect on apical dominance. TIBA, CCC and B.9 reduced mean internode length on all shoots, whereas GA increased internode length on the lower shoots only.CCC caused only a temporary check to growth, but the growth-retarding effects of B.9 and TIBA persisted throughout the growing season. The possible mode of action o...

With the aid of water culture and gravel culture growth-curves have been determined for tomatoes, based on leaf area and on the dry weight of leaves, stem, fruit and roots. Rectilinear increases were measured for the height and the leaf number and leaf area of the plants and parabolic increases for the dry weight of the leaves, stem, roots and fruit. Generative development decreased the extend of vegetative growth, which nevertheless continued to increase at least in a rectilinear fashion.

In order to investigate the effect of temperature on leaf production and transformation of photosynthetic product into various organs, the studies were carried out under both controlled environmental conditions and natural field condition. Obtained results are as follows: 1) Even without clipping, under higher temperature conditions, the growth of various organs decreases gradually, plants become weaker before long, and presents the symptom of summer depression. 2) The higher the temperature, the more the flower buds are formed, and the less the portion occupied by storage organs. And the preparations to regrowth become worse. 3) Becoming worse of preparations to regrowth under higher temperature conditions seems to be a result caused by adaptation to keep the balance between production and consumption. And as a result, the plants make their non-photosynthetic parts less relatively. 4) Maximum leaf-size is found under 15°C and 20°C temperature conditions, and it is found that under higher or lower than this optimum conditions leaf-size becomes smaller. 5) Not only the interval of leaflet emrgence but also that of its death become shorter under higher temperature, longer under lower temperature, but the increasing rate of living leaf number shown by the ratio of the former and the latter reaches maximum at 20°C and 25°C, and becomes less at 15°C and 30°C in accordance with this order. 6) It is found that the number of branches and its increasing rate reach maximum under 15°C and 20°C, and under hither or lower than this optimum conditions they become less. Flower bud initiation is subject to stimulation by long day and high temperature conditions. 7) The higher the temperature, the shorter the number of days required to expand leaflet fully. 8) Judging from the above stated facts, the apparence that total leaf area of the plant under higher temperature conditions may be attributed to the following facts; (1) the size of leaflet under higher temperature conditions is smaller than that of under lower temperature, and (2) lower increasing rate of branches and higher initiating rate of flower bud under higher temperature conditions make the increasing rate of living leaf number less.

SUMMARYA detailed study was made of the tillering of barley plants grown at densities which ranged from 50 to 1600 plants m–2. Throughout the season the initiation of tiller buds and their growth in length and leaf number were followed, and measurements were made of leaf sheath and lamina length and lamina width. A proportion of tillers died and their positions and times of death are given.Three phases of tillering were recognized. The first, tiller bud initiation, was little affected directly by density. During the second phase, buds did not grow or did grow and emerge from the subtending leaf sheath. If they grew, there was no difference in growth rate of tillers at different densities. At the higher densities fewer buds developed, and the morphology of those tillers which did grow was affected by density. This suggests that the growth of the tiller bud may be controlled by levels of endogenous gibberellin, while in the final stage, growth after emergence from the subtending leaf sheath, competition for light appears to be the factor which determines whether a tiller survives to produce an ear. The data are discussed in relation to the practical importance of tillering.

SUMMARY Several quotations of minimum leaf numbers for floral initiation are given in the literature, but it was thought desirable to obtain further evidence that they do represent, as claimed by Purvis and Gregory for rye, obligatory vegetative growth preceding the attainment of Klebs's Bliihreife. The effects of mineral starvation on leaf number, as in Purvis's original experiments, were therefore tested with Xanthium, Eupatorium adenophorum, and Celosia argentea. In each of these, near-constant leaf numbers are characteristic of plants induced to flower rapidly by continuous short-day treatment. In each, treatments such as starvation which retard vegetative growth do somewhat reduce the numbers. In Xanthium indeed, the concept of Bliihreife is superfluous, for the 8 leaves to be accounted for could be explained as the primordia present in the seed plus the extra leaves initiated during daylength induction. For the other two plants, on the other hand, the sum of these is still many short of the required number, and for them a con cept of Bliihreife expressed by leaf number is retained, but with the admitted doubt whether all factors controlling their flowering are yet known. Klebs in 1913 invented the term 'Bliihreife' for a postulated stage in the development of a plant signifying its 'ripeness' for environmental conditions to induce flowering. It is evident that he could not himself characterize the stage, save by the negative criterion that none of the environmental variants at his command would induce initiation in rosettes of Sempervivum funkii before the end of the summer.

The first experiment involving different explants and concentrations of 2,4-D and kinetin showed highly significant differences for length and weight of callus formed except interaction of callus weight. Leaf explant appeared to be best of all for callus length and weight when 1.0 mg/L 2,4-D + 0.25 mg/L kinetin concentration was used. Similarly, different explants versus different concentrations of BAP/GA 3 /IAA showed significant differences for shoot length and leaf number per plantlet and also for root length. However, interaction term confirmed node and node/internode explants produced better results in shoot length and number of leaves per plantlet when concentrations 1 .0 mg/L BAP + 0.1 mg/L GA 3 and 1.0 mg/L BAP + 0.2 mg/L GA 3 , 1.0 mg/L BAP + 0.4 mg/L GA 3 , respectively, were used. Similarly, internode explants produced better results for root length after 21 days plantlet -1 when concentration of 1.0 mg/L IAA + 0.25 mg/L GA 3 was used. Shoot tip explants also produced better results in root length after 28 days plantlet -1 when concentrations 1.0 mg/L IAA + 0.25 mg/L GA 3 were used. Key Words: In vitro, callus initiation, regeneration, potato. DOI: 10.3329/bjar.v34i3.3971 Bangladesh J. Agril. Res. 34(3) : 449-456, September 2009

1. This investigation was carried on from 1960 to 1963 with three varieties of Japanese persimmons (Jiro, Monpei and Hiratanenashi) to make clear the main factors connected with the yearly change of the average individual fruit weight of a tree. Fruits were thinned usually to one per bearing shoot in July of each year, except for on some of trees in 1963.2. When the correlation was observed between shoot length and leaf area, and between leaf number and leaf area respectively, its coefficient was higher in the former than in the latter. Consequently, fruit number per one meter length of shoot was employed as an indicator of fruit load on a tree, dividing the total number of fruits by the total length of non-bearing and bearing shoots.3. A significant negative correlation was always found between fruit load of a tree and average individual fruit weight. However, a significant positive correlation existed only occasionally, both between bearing shoot length and average individual fruit weight, and between seed number of a fruit and average individual fruit weight. Therefore, the fruit load of a tree seemed to have a deeper connection with the average individual fruit weight than the length of a bearing shoot and the seed number of a fruit.4. Average individual fruit weight varied from 150 to 250g in the yearly change of the same tree as well as among the different trees of the same year. The variation coefficient expressed as a measure of dispersion of individual fruit weights was 7 to 15% regardless of the fruit load. A significant positive correlation was always found between fruit load of a tree and its yield.

In trials in 1966-7, removal of the upper leaves of wheat and rye at heading gave lower yields of grain and straw than removal of the lower leaves. Removal of all leaves reduced grain yields of winter rye by 44% and winter wheat by 43%. The proportional increase in stem weight after flowering compared with that of ear weight, was appreciably greater in rye than in wheat. (Abstract retrieved from CAB Abstracts by CABI’s permission)

In rye cv. Petkus and Zelder the date of emergence of the flag leaves was almost the same for all plants irrespective of the number of leaves (10-13) produced. Correlation coefficients for the relationship between total leaf area and number of leaves were + 0.45 and + 0.44 and for that between number of spikelets per ear and number of leaves + 0.61 and + 0.69 for the 2 varieties, respectively. Average surface area per leaf increased with increasing number of leaves.-R.B. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Flower production of seedling plants of Gerbera was shown to be positively correlated with the number of lateral shoots and with the number of leaves per flower. The most productive plants were those which formed 2–5 lateral shoots during the first year and had a leaf flower ratio of 2–4. The number of lateral shoots at the moment the first flower bud became visible was strongly correlated with the number of lateral shoots after 1 year. There was a positive correlation between the number of lateral shoots and total number of leaves, but hardly at all between total leaf number and flower production, as the leaf flower ratio increased with the number of lateral shoots.

As strains of Verticillium with increased pathogenicity had originated in several crops and serious outbreaks of Verticillium dahliae Kleb. had occurred in New Zealand tobacco (Nicotiana tabacum L.), isolates from four different fields were compared for virulence in inoculated field trials. No significant differences were found. In the field the growth of infected tobacco was retarded, final leaf number increased, and internode length was shortened. Eight weeks after inoculation 93 percent of the plants showed some symptoms, whereas only 5 percent of uninoculated plants had symptoms. After 15 weeks the percentages of visibly affected plants were 100 and 68.5 respectively. As leaf numbers increased from 6 to 14 the proportion of leaves with symptoms diminished, but it increased rapidly after the plants had flowered.

In the previous paper (IV) it was reported that plants cultivated at the field belonging to Utsunomiya Tobacco Experiment Station produced greater number of leaves than those at the field belonging to Okayama Tobacco Expriment Station and that daily mean temperature was little different, however the diurnal variation of temperature was greater in the former than in the latter. Then studies were made on effects of diurnal variation of temperature upon the developmental responses of tobacco seedlings. Seedlings with 9 to 12 leaves of Hicks I-2 variety were used. In experiment I two temperature treatments were designed under 12hrs. day-length condition. In one of them daily mean temperature was 16°C and the diurnal range of it was 24°C. In the other, temperature during lightperiod was the same as the former, but temperature during dark-perid was higher by 9°C. Then the effect of temperature during dark-period upon the developmental responses was examined. Plants grew at higher rate and bore greater number of leaves under warm night than those under cool night. In experiment II three treatments on temperature were designed under 12hrs. day-length condition. Daily mean temperature was 16°C in all treatments. One was constant temperature (16°C), the others had the diurnal variation of temperature varied 23-9°C and 28-4°C respectively according to sine curve. The highest rate of leaf initiation was observed in the variation 23-9°C Plot and the lowest one in the variation 28-4°C Plot. In both the constant temperature Plot and the variation 23-9°C Plot, leaf initiation rate was slower with increasing of seeding-age at the beginning of treatment, however it differed little in the variation 28-4°C Plot. Plants bore the least number of leaves in the constant temperature Plot. In the variation 28-4°C Plot plants produced greater number of leaves than those in the variation 23-9°C Plot. Seedlings with more number of leaves at the beginning of treatment initiated floral primordia earlier, however little difference in total leaf number at flowering was observed in all plots.

Growth of flue-cured tobacco (Nicotiana tabacum L.), ‘NC2326,’ was studied under controlled conditions in the North Carolina State University Phytotron (Southeastern Plant Environment Laboratory) to determine the patterns of growth over a wide range of day/night temperatures. Day temperatures ranged from 18 to 34 C at 4-C intervals; night temperatures ranged from 14 to 30 C at 4-C intervals. The growth of seedlings from first leaf to transplant size (Experiment I) was determined weekly intervals under all possible day/night temperature combinations. Fresh weight, dry weight, and leaf number were affected to a greater extent by night than by day temperature. The minimum night temperature for growth lies between 18 and 22 C. The 34/30 treatment yielded maximum fresh and dry weights, while maximum leaf number occurred under the 34/26 treatment. Diurnal variation in temperature favored increased growth. During early stages of seedling growth fresh and dry weight accumulation exhibited a bimodal response to day temperature. The growth of plants from transplant size to appearance of the first flower (Experiment II) was studied under the following day/night temperatures: 34/30, 30/26, 26/22, 22/18, and 18/14. Whole-plant fresh and dry weights, leaf fresh and dry weights, leaf number, and plant height increased with temperature to 30/26, but decreased slightly at 34/30. Days.to.flower decreased with temperature to 26/22 and then increased at higher temperatures.

In the previous paper (I), the authors reported that in Setonaikai districts premature blossoming was frequently observed in tobacco plants transplanted at the age of 11th or 12th leaf. On the other hand, premature blossoming is scarcely observed in the Kanto provinces or the areas among Tyugoku Mountains. This experiment was carried out to make clear the causes of local differences of the developmental responses of tobacco seedlings. Three fields, which belonged to Kagoshima, Okayama and Utsunomiya Tobacco Experiment Station respectively, were selected with an eye on the different climatic conditions. Seedlings with 9 to 11 leaves of Hicks I-2 variety cultivated under the control condition (20-30°C, 12hrs.-light period) were sent from Okayama Tobacco Experiment Station to the other two experiment stations by rail in 15-20 hours. On April 2nd in 1963 these seedlings were transplanted to Okayama and Kagoshima fields and on April 17th in 1963 to Okayama and Utsunomiya fields at the same time. In the Kagoshima field leaves initiated at higher rate and plants bore greater number of leaves than those in the Okayama field. No difference in total leaf number among seedlings with different ages used for transplanting was observed in both fields. Temperature was higher in the Kagoshima field than that in the Okayama field throughout the growing season. Astronomical day-length in both fields differed little. Then it was thought that these differences in the developmental responses arose chiefly from temperature different among these two fields. Interdiurnal change of temperature was irregular in both fields, that caused no difference in total leaf number among seedlings with different ages used for transplanting. In the Utsunomiya field leaves initiated at lower rate than in the Okayama field. In the former however, plants bore greater number of leaves than those in the latter. Difference in total leaf number among seedlings with different ages used for transplanting was observed in the Okayama field, but not in the Utsunomiya field. Both astronomical day-length and daily mean temperatute were scarcely different among these two fields. However the diurnal variation of temperature differed; the diurnal range of it was greater in the Utsunomiya field than in the Okayama field. It was supposed that longer time of low temperature at night depressed the leaf initiation and longer time of high temperature at daytime retarded the flower-bud formation of tobacco seedlings in the Utsunomiya field.

The number of days before heading has hitherto been used to express developmental stages of rice plants, and it is known that the number of days before heading can also been used practically in case of a definite variety grown in a definite area. However, in fact, the number of days before heading is strongly affected by many factors such as varieties, time of seeding or transplanting, cultural conditions and so on. On the other hand, the number of leaves on the main culm is also affected by the factors mentioned above. Therefore, the authors have tried to clarify the relation between the leaf number index, which is possible to express the developmental stages of young panicles of rice plants, and the number of days before heading at various stages, and the following results have beed obtained. 1. The relation between the leaf number index (LNI) and the number of days before heading (DBH) is variable with varieties, time of seeding or transplanting and cultural conditions etc. For instance, the number of days before heading corresponding to a given developmental stage (a given LNI) is larger in late varieties than in early ones, in the case of an identical seeding time. Likewise, DBH is larger in early seeding time than in late one, in case of an identical variety being used. These facts suggests that the variation in the number of days before heading corresponding to a given leaf number index might be mainly governed by the number of days from seeding to heading (DSH). 2. The number of days before heading is divided by the number of days from seeding to heading and is multiplied by 100, and then its relation to the leaf number index has been examined, so that the time difference in the number of days before heading caused by various factors may be eliminated. As a result of it, relation between leaf number index and DBH/DSH ratio shows always a definite tendency irrespective of variation caused by varieties and other factors. Accordingly, the values of DBH/DSH have been proved to be effectively used for estimating each developmental stage of young panicles in rice.

1. Mature leaves of larkspur, for the aspects studied, bear a relationship to one another typical of growth sequences in single organs. 2. Slightly sigmoid curves were obtained when the characters (number of points per side, per middle, total, and area, length, and area/length) were plotted against physiological time intervals (leaf number). 3. Log-log plotting of some characters against others yields relative growth relationships expected from sigmoid developmental sequences. 4. The problem of the developmental factors underlying these relationships is briefly analyzed. 5. The number of points is in direct relationship to the area of the leaf, indicating that incision must be regarded as a segmentation of the area rather than a splitting in from the circumference. 6. The use of homologous organ series in problems of relative growth and the use of relative growth techniques in estimating degree of differentiation are discussed.

The auther has been made an experiment to see the influence of natural low temperature of planting time upon the developmental process of tabacco seedlings, which were grown under different conditions. The seedlings to be test were divided into six kinds by the difference of the next growing method, and each of them were separately cultured in green house (high temperature plot) and open field (natural low temperature plot.) respectively. The kind and the growing method of seedling. [table] The result of this experiment can be summarized as follows ; The growth and flowering of all plants exposed to natural low temperature were delayed compaired with that to high temperature, and their total leaf number has decreased. But an exception, in this case, was recognized ; the seedlings grown roughly in seed bed of open field were flowered very rapidly, and their total leaf has remarkably decreased. According to the above results, it is low temperature affects the development of tobacco plant as well general winter crops and accelerates at least, the flower initiation. Moreover, it is suggested that the reaction degree of seedlings itself to this temperature will be varied clearly by their different developmend and nature.

The purpose of this study was to find the most promising F1 hybrids by crossing several self-incompatible strains of induced pseudogamy in Matsushima No. 2 and Chiba No. 1 chinese cabbage. The authors obtained 48 F1 hybrids by crossing 23 self-incompatible strains. The seeds of these F1 hybrids were sown on the two different dates. The hybrid vigor and the various characteristics which appeared in these F1 hybrids, were observed. (1) In crossing these self-incompatible strains, hybrid vigor was affected by different cross-combi-nations and different sowing dates, and especially the total weight, head weight etc. were increas-ed by hybridization. (2) The rate of increase in F1 hybrid yield was greater than that of their parents, in both early and late sowing, and the variation in their yield was greater than those of other characteristics. It is thus possible to find a fairly productive F1 hybrid. (3) Generally, the degree of hybrid vigor which appeared in early maturity and leaf number was less in comparison with those of other charac-teristics. However, a few of these cross-combi-nation showed marked vigor in early maturity and leaf number characteristics. Therefore, it was possible to select the hybrids that matured earlier, and had more leaves per head than Matsushima No. 2. (4) There was correlation between a superior parent yield, an average yield of parents and F1 hybrid yield, respectively, but no correlation be-tween an inferior parent yield and F1 hybrid yield. The F1 hybrid resulting from crossing productive parents showed increased vigor, when their parents were homozygous. (5) In general, F1 hybrids resulting from the crossing of these self-incompatible strains did not have more excellent characteristics than those of standared variety, Matsushima No. 2. However, some of these F1 hybrids seemed markedly promising. Finally, we selected 6 F1 hybrids that had showed adaptability to early sowing and late sowing, which were superior in early maturity, yield, uniformity and disease-resistance (soft rot) to Matsushima No. 2.

Effects of single GA3, IAA and MH and of their combinations with GA3 in natural rhythm of day and night and in shade in day + darkness at night have been studied. The rise in leaf number as a result of many of the treatments did not result in any practical economic benefit to the tobacco crop because the rise in leaf number was not reflected in rise in leaf area and the dry weight. It was observed that GA3 had no growth-promoting influence on tobacco plants when grown in shade, rather increased the starvational death, but usual growth-promotion was more or less resumed when the plants were transferred to natural light. It is concluded, therefore, that GA3 was neither metabolized nor destroyed nor inactivated in any way inside the plant tissue even in 20 days but its action was temporarily inhibited in shade and was resumed again after the reception of light. The dependence of GA3 action on light may be either a photosynthesis or auxin-mediated mechanism.

It was made an attempt to know the safe and effective method of utilizing herbicide CAT in barley and wheat cultivations. 1.) The pot tests were carried out to investigate the circumstances of movement of t he chemical under various conditions combining several kinds of soil and amounts of rainfall, where the seedlings of rape and wheat were used as test plants. It was made clear that the chemical moved into the soil 3 cm depth from the surface, under the condition which had 20 mm rainfall on Nagano loam with a little water capacity and humus content. Some matters that demand special attention for use of the chemical were pointed out from this fact. 2) Differences were found on the germination phases in Alopecurus aequalis var. amurensis between the plants grown on plowed and non-plowed paddy fields. On the plowed paddy fields, plants can emerge easily from the deep parts under the ground. As it causes the growing of numerous number of weeds on the plowed paddy fields, othet suitable means togethet with the chemical should be adopted to weed control in such case. 3) The interrelation between the growing stages of wheat or Alopecurus aequalis var. amurensis and the chemical injuries was investigated. The chemical injury is raised in an early stage when the plants have not attained the leaf number of 2.5. Therefore, the attention should be paid for the growing stage when the chemical is used.

1. Plants of Callistephus chinensis cv. ‘Giant Comet’ were subjected to photoperiods of 8 or 16 hours. In short day (SD) a much greater number of leaves was formed than in long day (LD) before the terminal inflorescence was initiated. By transferring plants from LD to SD at weekly intervals it was established that in LD floral induction is completed about 6 weeks after sowing. 2. Inflorescence development proceeds faster in SD than in LD. Plants in continuous SD or LD flower almost simultaneously. Plants transferred from LD to SD six weeks after sowing, flower about a month earlier than those plants grown entirely in LD. 3. Gibberellic acid (GA3) did not affect inflorescence initiation in LD. In SD, however, GA3 applications reduced the number of leaves formed before the inflorescence. The maximal effect, obtained by spraying with a solution of 25 mg GA3/1 during 30 days, halved the difference in leaf number of untreated plants in LD and SD. The same effect was obtained when plants were sprayed 10, 20 or 30 times during this 30 day period. 4. Manipulation of the photoperiod allowed the development of a method to grow two generations within one year. This method, which is being used to speed up a breeding project, is briefly described.

In these investigations, relationship between total number of leaves of a tobacco plant (bright tobacco var. BRIGHT YELLOW), which was closely related to time of flower initiation and length of duration in which plants were grown on water-logged soil, was examined under field conditions in normal season. In the first experiment, the three different sized seedlings (with 8, 10 and 12 leaves) were subjected respectively to water-logging for various durations (0, 1, 3, 6, 15 and 20 days) after transplanting, in order to determine the influence of both growth stage of seedling and length of treatment duration. As the results, in case of 8 leaver-seedling, these treatments had relatively little or no effect upon the number of leaves and in 12 leaves-seedling, it tended to decrease in total number of leaves markedly with length of durations, whereas in 10 leaves it was slightly decreased in case of shorter duration (1-3 days), but reversely increased in longer duration (15∼2O days) compared with that of normal plant. In the second experiment, all combination of three growth stages (8, 10 and 12 leaves), two periods until beginning of treatment from transplanting (0 and 14 days) and two water-logged durations (3 and 15 days) were tested in order to recognize above-mentioned relationships. As the results, total number of leaves, which were treated at 14 th day after Transplanting was decreased compared with that treated just at the time of transplanting, except in case of three days duration with 8 leaves-seedling and fifteen days with 12 leaves. Especially, the remarkable decreases of total number of leaves was caused by only three days treatment and in these plants was observed earlier blooming than normal, if the growth stage of plant shown by external leaf number reached more than 12 leaves. In the third experiment, the three different sized seedlings as above mentioned were transplanted at the same time, and then in 12 leaves-seedling were treated just at the time of transplanting, where as the same treatment was begun at 7 th day after transplanting in 10 leaves-seedling and at 14 th day in 8 leaves, when their external leaf number reached to 12 leaves and continued respectively for various durations (0, 1, 3, 6, and 15 days). As the results, in longer duration of treatment as fifteen days, there was less variation in decrease of total number of leaves among seedlings with various growth stages However, it showed in shorter duration that total number of leaves was decreased markedly in case of 12 leaves-seedling. From these results, it was concluded that there was a limiting factor showed by the growth stage of tobacco plant for decrease of total number of leaves caused by long duration of water-logging, as shown in previous paper, and in one stage before this limit, increase of total number of leaves occurred, but in another stage over this limit, water-logging duration required to induce the remarkable decrease was reached to only three days.

Six parents and 15 hybrids of sorghum (Sorghum bicolor (L.) Moench) were grown for 3 years at Manhattan and Ashland, Kansas and observed for leaf number and time of flowering. Three parents and two hybrids were grown at Plainview, Texas for 1 year and observed for leaf number, time of floral initiation and of flowering. The data are interpreted to mean that earliness of hybrids results largely from more rapid development of the meristem prior to floral initiation and to more rapid development of the panicle in hybrids.

In order to make clear the peculiarity of growth habit of rice plant in warmer regions, and to obtain fundamental data of clinical diagnosis based on its external characteristics, the present investigation concerning with growing process of leaves according to the leaf order was carried out. The results obtained are summarized as follows: 1. Elongation process of the leaves (blades and sheaths) according to their leaf orders were shown in Fig. 1 (in nursery bed period) and Fig. 2 (in transplanted field period). 2. Elongation periods of the leaves are shown in Fig. 3. These periods increased in length gradually according to the leaf order from the 1st blade to the 7th blade, where the firstpeak occured, and then decreased sucessively until the 10th blade which showed the minimum length of period. In higher odered leaves than the 11th blade, these periods were increased again gradually. Elongation period of each leaf sheaths coincides almost with that of the next higher ordered leaf blades. 3. Leaf period of each leab showed a tendency to increase gradually from the lower to the higher. The difference in the life duration between the 1st and the 9th leaves was not so great, but those among the upper order leaves beyond the 12th were of some significance.(Fig. 3) 4. Blade-weight per leaf changed regularly according to the leaf order as shown in Fig. 4 (A). The weight increased regularly according to the elongation of blade, and the maximum weight was reached shortly after the completion of elongation. The decrease of the blade weight from the maximum was not so large as that of sheath. 5. sheath-weight per leaf changed in the similar way as that of the blade as shown in Fig. 4 (B). The difference of weight between the sheath and the blade according to the growing stage seemed to show heavy decrease after the maximum weight was attained, and this tendency was especially remarkable in sheaths of 12∼15th leaves. This decrease of weight correlated closely with starch translocation in sheath. 6. Between the two groups of the leaf, i. e. a lower group of 1∼11th leaves and the upper one of 12∼16th, the authors found a distinct difference in the sheath blade weight ratio. It might be related to the growth phase transition from the vegetative to the reproductive stage of the plant. 7. Developmental changes of leaf number and weight per plant were shown in Flg. 5. the number of green leafblades was largest at the developing stage of young ear, but their weight was heaviest at the time immediately before heading. The number and weight of green leaf sheaths were largest at the same time as the former.

Potted cabbage plants were grown in growth chambers at 25 degrees day and 15 degrees night and hardened successively at 5, 0, and -3 degrees . Leaf growth was determined by measuring leaf area, hardiness by freezing at a series of temperatures and determining percent survival. Leaf growth increased progessively with leaf number, reaching a maximum rate of growth and final area in the tenth and eleventh leaves when the plants become potbound. Leaf growth continued at hardening temperatures of 5 or 0 degrees , the Q(10) being 2.0 to 2.5. Ability to harden also increased with leaf number, paralleling the growth rate of the leaves just before hardening as well as the growth rate and the total growth during hardening. The above results were similar whether prolonged (several weeks) or brief (24 hr) hardening was utilized.

In the phytotron of our Institute the effect was studied of different day and night temperatures on the shoot growth of first- and second-year seedlings of Limburgse Boskriek (Prunus avium L.) grown under natural daylength conditions. It was found that, after termination of growth, significant differences occurring simultaneously in shoot length and leaf number between the temperature treatments were mainly due to the effect of the day or night temperature on the duration of growth. In some cases these differences were also influenced by the effect of temperature on the rate of growth. Within the range of temperatures studied, no effect of the night temperature on the rate of growth was observed.

The present paper is a report on the formation of first internode and beginning of internodal extention in rice shoots, and it also describes the varietal differences and ecological responses to the varying times of cultivation. Definitive nodes and internodes are here defined as those that are clearly delimited in longitudinal median sections of living shoots as observed using dissecting microscope. By these easy methods, the first discernible internordal lacunae are considered here as an index of internodal extension. From the results of this observation on the morphogenetic process, the author proposed that the stem development may be divided into the following three phases; viz. previous phase of internodal lacunae formation named "Primitive phase", process of subtle elongation of basel telescoped lacunae (Crown-internodes) named as "Primary phase", and the following phase showing the rapid and long extension of upper internodes (Culm-internodes) named as "Secondary phase". It is observed that the stage of first internodal formation in the Primary phase may correspond to time far previous to differentiation of panicle primordium. The plant-age as measured by the number of leaves is about 5.5. And in most plants, first extended internode is that between 5th and 6th node, however, the locus of this node keeps lower in short-term varieties and in plants planted late, but upper in long-term varieties and in early planted plants. The number of extended internodes in Primary phase may be found 5 or 6 in most plants, and are less in short term varieties but more in long-term varieties. However, ecological variations due to the varying of planting times are a little. These internodes are 1-2 mm in length at the beginning of formation, and are extended just about 3 mm in full length. And the internodes which are extended over 3 mm in length may be regarded as the internodes of Secondary phase. At the stage of onset in Secondary phase, the panicle is 0.4∼1.0 mm in length, and the stage ranges from the branch differentiation to early time of spikelet formation. And the plantage is 11.0∼14.0 leaves, leaf number index is 83 to 87, and the Secondary extension of internode begins from the node of 10∼13th leaf. Each above-mentioned value is revealing the range of varietal differences. It seems that the "crown" of Grasses may be divided into two types with or without of "crown-internode"-Rice-type crown (with) and Wheat-type crown (without). From the results of this studies, the author stated that the simple method using dissecting microscope may be useful for identifying the internodal formation and extension not only at the Secondary phase but also at the Primary phase, without any trouble as by paraffin method.

The number of leaves per verticil in the material examined varied from 2 to 16. The variation in leaf number from verticil to verticil cannot be correlated to the splitting of primordia, junctional forces, binding whorls, acropetally developing forces from the stele, positions of leaf traces, nor to a constant angle between leaf insertions at every node. In tracing the development of leaves it is clear that nodes bearing leaves are produced in partially differentiated internodal tissue, as the apical thimble enlarges and grows. The leaves are not initiated at a constant distance from the tip and the larger the circumference of the leaf insertion disc, the larger is the number of leaves. The centers of the leaf primordia are circa 50 microns apart in each verticil. The initiation of leaves is traced in both aerial and aquatic apices using material from a single clone and also from a variety of sources. Aerial apices are usually smaller than aquatic ones and are of a different shape. However, the primordia are apparently the same until they are 50 microns long. Seven cells in the second layer divide periclinally to initiate each primordium. The study suggests that each of these groups of seven cells originates from anticlinal divisions of a single cell. The several cells separating the groups also originate from a single cell.

For the purpose of studying the effect of selection within a population of the small turnip “Kanamachi”, the heritabilities and the degrees of dominance were estimated for weight, leaf number, neck diameter, root thickness, index of root shape and tap-rot diameter by using the data of biparental progenies within a population (the experimental procedure was the same as Experiment I. of COMSTOCK and ROBINSON, 1952)and the double of regression foefficient of progeny on male parent and on female parent. The degree of dominance was estimated from “a”=√(2(F-M)/M) and σa2/σg2 by the method of Comstock et al., It was considered that the heritablilty values estimated were nearly zero weight and root diameter, and were low (5-20 percent) in the other characters except the index of root shape which showed 33-36 percent estimates. The estimates obtained by the three method agreed fairly well. In the root shape, no dominance was observed, but in the others, overdominance was detected by this mithod. Granting that overdominance observed in this experimint is partly caused by overestimation due to the method adopted, it still seems right to conclude that strong dominance effect of genes affects thses chearacters. Finally, in thses characters except index of root shape, the effect of selection cannot be exaected, because hiritability values are very low and degrees of dominance which may be overdominance are fairly higy.

When potato plants cv. King Edward are inoculated with Phytophthora infestans by a standard method, which is described, four types of leaf reaction can be distinguished: (1) successful infection with fungal spread giving normal lesions, (2) relative hypersensitivity (as defined), (3) hypersensitivity (as defined) and (4) no visible symptoms. Leaves showing these reactions form zones on growing plants and up to three such zones can be present. In very young plants all leaves are very susceptible and show normal lesions. In older plants up to flowering time reaction types 2, 3 and 4 appear in a zone intermediate between susceptible zones with reaction type 1 at the top and base of the plant. In plants immediately after flowering there may be a less well-defined susceptible zone at the top of the plant so that temporarily only two clear zones are present. With further increase in leaf number the susceptible zone at the base increases in size, the intermediate more resistant zone remains constant in extent and a susceptible zone is again present at the top. The overall resistance of plants therefore varies with age and may be related to the occurrence of different reaction types. These reactions have been shown by plants grown in the open and in the glasshouse but are more apparent on leaves attached to the plant and, with the exception of normal lesions, are much less frequently seen on detached leaves. Reactions of leaves on various kinds of branches were similar to those on main stems except that leaves on flower shoots showed more frequent occurrence of reaction types 3 and 4. When the concentration of sporangia in the inoculum applied to leaves on main stems was 5000/ml reaction types 3 and 4 were most frequent but were somewhat fewer at a concentration of 10000 sporangia/ml and least at concentrations between 25000 and 100000 sporangia/ml.

The effect of night temperature upon the development of some crop plants was observed, taking wheat, barley, rye, pea and french bean as test object. Each plants which sowned at suitable season were adequately managed. Those plants were cultured to the date of harvest in two green houses, the one being heated during night time to raise the night temperature average 4°C. higher than the other (control) (Fig. I). The plants in both green houses were investigated with regard to the growth rate, flowering and fruiting habit; Some of the interesting observations are recorded here. 1). Effect upon the growth rate: Warm night, generally, were promoted the growth of the plants, but could not give influence to the leaf number (Tab. 1). French bean, however, were slower in opposition by warm night (Fig. 5). The growth of ovary of pea were promoted by warm night. (Fig. 4). 2). Effect upon the heading and flowering: The heading of wheat, rye and barley were promoted by warm night; the promotion of wheat were one month's duration, but other plants were seven to ten days (Fig.2). The flowering of pea var. AOTURUNASI were promoted by warm night, but var. KINUSAYA were delayed (Fig. 3). The flowering of red-flower french bean were clearly by warm night, or the flowering percentage was 40%, but at warm night was 0.29% (Tab. 4). And observed that the developments of pollen mother cell were retarded by warm night temperature (Fig. 6). 3). Effect upon the harvested materials: Some investigation of the harvested materials were operated only about wheat, barley, and rye. Those plants, generally, at warm night were retarded the organization of the spiklet; grain number, size of spiklet, etc., but the grains were clearly substantial (Tab. 1 & 2).

Bulb development in the onion plant, which occurs in response to the stimulus of long days, has two main morphological features : swelling of the base of the pseudostem and the formation of scales from leaf initials produced at the stem apex. The swelling may be expressed as the 'bulbing ratio', i.e. the ratio of the maximum diameter at the base to the minimum at the neck, but this is a somewhat insensitive measure under adverse light conditions and no ratio can be specified at which bulbing is first apparent. In the absence of bulbing, leaf initials have at all stages of development a blade longer than the leaf sheath, giving a 'leaf ratio' of blade/sheath at all times greater than unity. In scale formation, when bulb development begins, the sheath of a small initial starts to grow sooner than in foliage leaf formation and blade growth is suppressed ; the leaf ratio therefore falls rapidly below unity and this is diagnostic of bulbing. Characteristic graphs of leaf ratio plotted against leaf number from the apex demonstrate the stage of bulbing reached and a fall in leaf ratio from near the apex in such a graph can indicate the beginning of bulbing before any actual scales (with ratios less than unity) have been formed. In normally grown plants, differentiation into foliage leaves or scales appears to take place when the initials reach about i mm in length. When the incidence of bulbing within a treatment is very variable, difficulties arise in averaging the leaf ratio curves for the different plants. Mean number of scales per plant, or mean minimum leaf ratio, may then be used as measures of bulbing. Heavy shading in winter was found to delay but not prevent the bulbing of those plants which survived. 'Buds', consisting of a portion of stem with the apex surrounded by leaf initials, but no scales, were dissected out from onion sets and cultured aseptically in tubes. Limited growth was obtained and rooting occurred in some cases. In the presence of sucrose, swelling of leaf sheaths and reduction of the leaf ratios took place; these responses increased with sucrose concentration. Glucose similarly stimulated bulbing but high osmotic pressure caused by mannitol or mineral nutrients had no effect. Rooting appeared to reduce the degree of bulbing, possibly by competing for carbohydrate supply. The bulb development in these sterile 1 Present Address: Coffee Research Station, Lyamungu, Moshi, Tanganyika. 2 The experiments described form part of the work presented for the degree of Ph.D. of the University of Reading. Journal of Experimental Botany, Vol. 16, No. 46, pp. 128-144, January 1965. This content downloaded from 207.46.13.149 on Wed, 28 Sep 2016 05:17:11 UTC All use subject to http://about.jstor.org/terms Heath and Hollies—Studies in Physiology of Onion Plant. VI 129 cultures was most unusual in occurring in short photoperiods and the possibility of a residue of 'bulbing hormone' being stored in sets is discussed.

1. Increasing light intensity under long (16-hour) and short (10-hour) photoperiods of fluorescent light increased the rate of primordium production and of floral development. 2. The photoperiodic response, in terms of floral development and leaf number, was not great under the fluorescent light source in comparison with responses reported under natural or incandescent light. 3. The various developmental and growth responses of the apex to variations in daylength or light intensity were closely related, suggesting an over-all controlling mechanism. 4. The age of the light source had no effect on apical development under comparable light intensities, but variations in the rooting medium had a profound influence, indicating the necessity for standardization of this factor in photoperiodic experiments.

In order to make clear the cause of growth reterdation of Ladino clover induced by high temperature during the summer, the influences of high temperature on dry matter and leaf production of the plant were studied. The plants were grown under controlled environmental conditions with temperatures of 15°C, 20°C, 25°C and 30°C for 31 days after cutting. The total amount of dry matter production at the high temperature (30°C) was less than that at the lower temperatures (below 25°C). The expansions of leaf area in early period of regrowth were more rapid at the higher temperatures than at the lower temperatures, but those in middle and later period were more rapid at the lower temperatures than at high temperatures. The increasing rate of living leaf number decreased remarkably with advancement of the regrowth period at the higher temperatures (especially 30°C). The remarkable depletion of increasing rate of living leaf number at the higher temperatures was caused by both the decrease of emergences and life spans of leaves. From these results, it may be concluded that the depletion of dry matter productivity at the high temperature (30°C) is caused by the decrease of lear area affected by the decrease of emergances and life spans of leaves.

In a field experiment Hilgendorf wheat was found to initiate and produce ears earlier than Aotea, Arawa, and Cross Seven. Under controlled conditions none of the varieties tested showed an obligatory requirement for vernalisation, although Hilgendorf responded more strongly than the other wheats. Vernalisation caused ears to be initiated earlier and at a lower leaf number provided plants were exposed subsequently to continuous light or 14-hour days; in a to-hour day it had no effect. The length of the photoperiod influenced time to initiation and ear emergence as well as the number of leaves appearing at those stages. All varieties flowered in short days (10 hours), although only after 18-19 weeks from sowing. The field performance of wheat is examined on the basis of results obtained under controlled conditions.

Effects of temperature in seed-bed and field upon premature blossoming of tobacco plants were examined. The flue-cured variety, Hicks I-2 was used. In expriment 1, 9-12th leaf seedlings were grown under two different seed-bed conditions. The one was the commercial seed-bed covered with vinyl-film, the other a seed-bed set in a greenhouse. Minimum temperature was lower in the former by ca. 8°C as compared with that in the latter. These seedlings grown under different conditions were transplanted to the fiield and the same ones were transferred to the phytotron maintained at 20°C under natural day-length condition no April 8th in 1962. Plants cultivated in the fiield showed the same trends reported in the previous paper (I). The more advanced in age the seedling transplanted in the field, the earlier the flowering date, the lower the plant height and moreover the less number of leaves. But with plants transplanted from the greenhouse to the field, these trends were less observable. On the other hand, plants produced greater number of leaves in the phytotron than those in the field. And with plants cultivated in the phytotron, difference was not observed in total leaf number among seedlings with different ages, accompanying with no effect of the seed-bed condition upon the developmental responses of tobacco seedlings. These facts suggested that it was not day-length but temperature, especially in the field, that caused differences in total leaf number. In experiment II developmental responses of tobacco seedlings were examined in 1962 and 1964. Seedlings of 8-12th leaf stage cultivated in the commercial seed-bed were transplanted to the field on April 12th in 1962 and on April 13th in 1964 respectively. The same results as reported in the previous paper (I) were obtained in 1962. But in 1964, leaves were produced at higher rate and no difference in time for flower-bud formation among seedlings with different ages was observed. Consequently, plants bore greater number of leaves in contrast to that in 1962, and total leaf number increased with increased age of seedlings used for transplanting. The reason why these phenomena occured was able to be explained by comparing the changing pattern of diural mean temperature in both years. That is to say, in 1964 diural mean temperature was higher throughout the growing season as compared with that in 1962. But diural temperature rose gradually in 1962, and did not so in 1964. The development of tobacco seedlings was greatly influenced by temperature and the difference in total leaf number among seedlings with different ages arose chiefly from the changing pattern of diural temperature, which was confirmed in several experiments carried out by many procedures.