Apex Length Research Articles

A Statistical Analysis of the Stone Arrow Heads Buried in the Grave Pits of Jomon Period.

In this article, the authors intended to prove statistically that the stone arrow heads which were buried in grave pits had been selected from those used in daily life, and/or intentionally made for grave goods (funerary objects).The materials used were stone arrow heads unearthed from a grave pit and from other areas in the same site. The site belongs to the latest Jomon period, and is located at Satsukari in the southern part of Hokkaido. The excavation was undertaken by the members of the Historical Museum of Hokkaido during the period of 1971 through 73.The investigation was carried out using a variance analysis method to prove whether the variances of measurements of the stone arrow heads differed between those excavated from the grave pit (Group 1) and from the other areas of the site (Group 2). The numbers of materials were 57 for Group 1 and 62 for Group 2.The measurements made were maximum length (F in figure 2), maximum breadth (C), maximum thickness, apex length (D), base length (E), and weight, the line through the middle of the arrow head in figure 2 being the reference line.The test of difference in means showed that the significant differences were recognized in only two measurements, maximum length and apex length, and in both cases Group 2 showed smaller mean values than the Group 1. This fact appears to prove that the arrow heads in Group 2 were worn out by daily use. In contrast to this, insignificant differences between Groups 1 and 2 might show that the arrow heads of both groups belonged to the same population.On the other hand, the variance analysis showed that the variances for all the measurements were larger in Group 2 than in Group 1. The results apparently show that the arrow heads from the grave pit might have been selected intentionally on the basis of a certain standard.Thus, it may be safely emphasized that the statistical analysis on the stone arrow heads from the Satsukari site in Hokkaido proved intentional selection of those buried in the grave pits. In addition, it is very probable that the people of the site used relatively new artifacts when they prayed for a departed soul.

Early spring and late autumn response to applied nitrogen in four grasses

SummaryThe regrowth of Aberystwyth S. 23 perennial ryegrass, S. 24 perennial ryegrass, S. 59 red fescue and S. 170 tall fescue was studied in field swards, comparing four levels of applied nitrogen, for 8 weeks following a clearing cut. The clearing cuts were in mid-October, mid-February and mid-March in each of 3 years, different plots being used on each occasion.The application of N increased the number of leaf primordia, the number of un-emerged leaves, the rate of leaf emergence and death, leaf blade length, width and weight, sheath length, number of leaves per unit area of ground and proportion of green tissue in total yield. The application of N had little effect on the number of leaves per tiller and tended to reduce weight per unit area of leaf blade. The increase in size, weight and number of leaf blades appeared to be major reasons for the positive effect of applied N on yield, previously reported; and the increase in sheath length contributed to the increase in proportion of yield above 4 cm. Rate of leaf extension was not closely related to yield and was more sensitive to temperature than was yield. Changes during regrowth in blade and sheath length helped to explain changes in weight per tiller, previously reported. The effects of improving weather conditions in late winter/early spring were similar to the effects of applied N: larger, heavier leaf blades, longer sheaths, a taller canopy, a lower proportion of dead material, younger leaves. The length of shoot apex per leaf primordium was relatively constant. Leaves continued to emerge, at a slow rate, in the period December–February. S. 170 had the biggest leaves, particularly in May, and the slowest rate of leaf turnover. Rate of leaf extension was increased by applied N more, on average, in the ryegrasses than in the fescues.

Determination of spikelet number in wheat. III.* Effect of varying temperature on ear development

The effects on rate of development and spikelet number per ear in eight wheat cultivars grown at various temperatures (16/9, 23/16, and 30/23°C for 8/16 hr) throughout or transferred from one temperature to another at floral initiation were studied under normal (12.5–14.0 hr) and 24 hr photoperiods. Under a 24 hr photoperiod, the durations of the vegetative, spikelet and elongation phases, and spikelet number per ear decreased as the temperature increased from 16/9 to 30/23°C in all cultivars. The rate of spikelet initiation increased as temperature increased from 16/9 to 23/16° in most cultivars, but further increase in temperature caused a variable response. Under a normal photoperiod, increasing the temperature from 16/9 to 23/16°C changed spikelet number little, but further increase in temperature decreased it in most cultivars. The rate of initiation increased, but the durations of the vegetative, spikelet and elongation phases, and the apex length at floral initiation decreased in all cultivars as the temperature increased from 16/9 to 23/16°; with further increase in temperature, the rate of initiation, apex length and duration of the elongation phase decreased in most cultivars, but the durations of the vegetative and spikelet phases either increased or changed little. Variation in the number of spikelets per ear in relation to variation in the factors considered to be its possible determinants is discussed with a view to understanding the control of spikelet number. ___________________ *Part II, Aust. J. Agric. Res., 28: 575 (1977).

Effect of phosphorus applied as superphosphate on rate of development and spikelet number per ear of different cultivars of wheat

The effects of adding phosphorus (40 kg of phosphorus ha-1) at sowing on rate of development, spikelet number per ear, rate of spikelet initiation, apex length at floral initiation, and leaf number at ear emergence of the main shoot of seven wheat cultivars were studied under a 16 hr photoperiod at a constant temperature of 20°C. Phosphorus additions increased the spikelet number per ear, rate of spikelet initiation, and apex length significantly in all wheats, but had no effect on the duration of the vegetative phase, spikelet phase or elongation phase, or on leaf number. The increase in spikelet number was due to an increase of spikelet initiation. All wheats responded similarly to addition of phosphorus.

Determination of spikelet number in wheat. II.* Effect of varying light level on ear development

The effects of two light levels (0.98 and 4.90 cal cm-2 hr-1) on rate of development and spikelet number per ear were studied in eight wheat cultivars grown under a 16 hr photoperiod at 20°C. The objective was to ascertain how light affects spikelet number. At the lower light level the durations of the vegetative, spikelet and ear elongation phases were greater, but the number of spikelets per ear, number of phytomers present at floral initiation, final leaf number, number of phytomers that were converted into spikelets, apex length at floral initiation and rate of spikelet initiation were smaller than at the higher light level. Responses to varying light level for a11 these parameters were similar for different cultivars, but the sizes of the responses differed. Within a given cultivar, an increase in spikelet number was associated with longer apices at floral initiation and a higher rate of spikelet initiation. It was concluded that these two factors are important determinants of spikelet number. ___________________ *Part I, Aust. J. Agric, Res., 28: 565 (1977).

Anatomical Changes in the Shoot Tip of Wheat After Exposure to Drought Stress1

Shoot apices of 3 to 4‐week‐old winter wheat (Triticum aestivum L.) seedlings of cultivars ‘Ponca’ and ‘Cheyenne’ were examined and described anatomically before and after exposure to drought stress. Drought caused the following changes: thickened cell walls in apical and subapical regions, abundant peri‐ and anti‐clinal divisions with granulation and absence of protoplasts of some cells in the sub‐apical region, plasmolysis of some cells, lack of distinct zonation, and increased lateral bud formation. Apex length in both cultivars was comparable in controls but length more than doubled in Cheyenne with drought stress while drought‐susceptible Ponca changed very little. The distance between the apex tip and the first differentiated procambial cells was greatest in control Cheyenne and decreased with drought to less than onehalf in plants droughted 8 days. This distance to procambium decreased in Ponca with slight drought, then increased with additional drought stress. It is suggested that several of these changes may be responsible for the eventual death of the plant from severe drought.

Floral initiation in Lolium temulentum L.: the role of phytochrome in the responses to red and far-red light

The possibility that phytochrome is involved in the promotion of flowering by far-red light was investigated. The addition of far-red (FR) to a day extension with red (R) light promotes inflorescence initiation in Lolium. A 2-hour interruption with darkness also promoted flowering compared with the uninterrupted red light control; apex length was further increased by a 10-minute FR irradiation given before the 2-hour dark interruption and was decreased by 10-minutes of R light given in the middle: both FR promotion and R inhibition were reversed by R and FR respectively. Apex length increased approximately linearly with increasing duration of dark interruption up to at least 2 1/2 hours. When varying ratios of R:FR light were substituted for a 2-hour dark period, apex length was increasingly depressed as the % R was increased above 25%; no difference between 25% R/75% FR and 100% FR could be detected. Apex length was inversely linearly related to the calculated [Pfr]/[P] ratios above about 40% Pfr.FR promoted flowering when given during a 5-hour interruption of a day extension with R light but, between 0.25 and 0.90 J m(2) s(-1), there was no effect of intensity of FR; at 0.11 J m(-2) s(-1) apex length was shorter than at 0.25 J m(-2) s(-1) but longer than in darkness. When the duration of FR (from the beginning of a dark interruption of a day extension with R) was varied, apex length increased with increasing duration of FR up to 1 1/4 to 2 hours but further increasing the duration of FR did not promote flowering more.The results implicate phytochrome in the promotion of flowering by FR light. It has been demonstrated that a low [Pfr]/[P] ratio (less than present in 25% R/75% FR) is needed over a relatively long period of time: this explains why a relatively high proportion of FR light must be added to R for several hours in order to give maximum promotion of flowering. It is concluded that, in Lolium, the increased flowering response to FR light is brought about by a reduction of [Pfr]/[P] ratio at the appropriate time, although the possibility that another effect of far-red is also involved has not been rigorously excluded.

New and Little-Known Taxa of Merremia Hall. f. (Convolvulaceae) from North-East Africa

These notes mainly concern Merremia semisagitta (Peter) Dandy and its allies which form a difficult group of species. The following additional published names are involved-Ipomoea candei (Terrac.) Chiov., Merremia gregorii Rendle, M. pedata (Choisy) Hall. f. and var. gracilis Hall. f., Ipomoea psilophylla Steud. nomen nudum, Ipomoea stenophyton Chiov. and Merremia subpalmata Verdc. Several gatherings from north-east Africa were put aside many years ago for further study, since they did not appear to be referable to any of the above, and, at the time, there was a distinct possibility that the collectors concerned would be able to make further journeys to collect more material. Since this has now proved impossible, an account of the group is given based on what material is available. The main characters appear to be the indumentum, nature and degree of lobing of the leaves, shape of the segments, petiole length, sepal length and shape of apex, corolla length and seeds. Other characters such as flower colour may be valuable but have been inadequately documented by collectors. Further collecting will unquestionably modify some of my conclusions. A key to the group follows.

Plant Population Induced Growth Correlations in the Barley Plant Main Shoot and Possible Hormonal Mechanisms

A morphogenetic study, from the first-leaf stage onwards, was made of barley plants grown at a range of plant populations from 50 to 1600 plants m~2. Increasing density reduced leaf number from 10-2 to 8 and caused stem internode elongation to start earlier at a lower node. Final stem length was reduced due to earlier cessation of growth. The lamina and sheath length of the lower leaves was increased with increasing density, and lamina width was de creased. At the highest density the apex reached the double ridge stage 6 days earlier than at the lowest density, and this difference persisted throughout the development of the apex. The rate of primordium production was little affected by density, but the duration was markedly affected. Primordium production stopped abruptly, first at the highest density, and then successively at the lower densities. At this stage changes were seen at the tip of the apex, and eventually the 10 distal primordia died. There were small differences in the length of shoot apex or ear during growth, but earlier cessation of growth in the higher densities led to a shorter ear. Growth of the internodes of the floral apex started first at the high density. These observations suggest that plants grown at high densities had a high concentration of gibberellins (GA) in their tissues. The promotion of apex development by the higher concentra tion of GA gave rise to earlier competition for nutrients diffusing through the apex. This lead to starvation of the tip of the apex and earlier death of this region and, consequently, fewer spikelets. Differences in the light environment of the plants, either intensity or red/far red ratio, most probably brought about the differences in GA.

Studio Comparativo della Struttura e del Ciclo Biologico di Due Diatomee di Acqua Dolce:Navicula MinimaGrun. ENavicula SeminulumGrun: II. Struttura e Ciclo Biologico: diNavicula SeminulumGrun. ColtivataIn Vitro

Abstract Comparative study of the structure and of the biological cycle of two fresh water diatoms: « Navicula minima » Grun. and « Navicula seminulum » Grun. II. Structure and biological cycle of « Navicula seminulum » Grun. cultivated « in vitro ». — The Navicula seminulum Grun. was isolated in a clonal culture adopting the cultural soil agarized by Tanada. The investigations were conducted in a particular way in two clones, even though very similar to each other, and, for a better definition of the « type » studied, the integral description of the diatom under examination made by various authors was reported. It was revealed that the existent divergences on this matter often are notable also in connection with the institution of numerous varieties within the species, of which the variety intermedia Hustedt, the variety radiosa Hustedt, the var. Bergii A. Cleve-Euler, the var. brevis A. Cleve-Euler, the var. fragilarioides Grun., and others, whose validity is not yet demonstrated on the basis of deepened studies. The biological cycle of the N. seminulum Grun. occurs according to the observed procedures for the N. minima Grun., even though the maximum length is about 18–20 μ and the minimum around 4 μ. The cells enter into sexual reproduction when they reach dimensions of about 8,5 μ, on the condition that the nutritious conditions are of the best. The gamy occurs between two partners, one of which pours its entire protoplast into the other through a short canal for copulation, behaving, therefore, as a masculine component. The auxozygotes restore the maximum dimensions of the cells and the cycle repeats itself once more, spending on the average about 4 to 5 months. During the vegetative multiplication the proportions between the length of the axis at its apex and that across the apex length alterred, passing from a maximum value of about 4 to a minimum value of about 1,30; this phenomenon was represented graphically by means of lines of regression. The form of the valve, for some reason, undergoes a gradual modification, passing from a linear-elliptical form, with evident swelling in the middle part and characteristically rounded extremity, to a form simply elliptical and, at times, not quite round. As regards the structure of the frustule, the N. seminulum presents an axial area, narrow and linear, an ample central area enlarged transversally, and striae very evident in numebr of 18–20 in 10 μ. The wall of the frustule, examined by the electric microscope, appears to be of the laminar type with striae constituted of coupled rows of holes disposed in an alternate manner. This structural element is certainly of considerable diagnostic importance, and will have to keep itself present when one wishes to relate to N. seminulum Grun. several varieties, mentioned a little above, whose systematic position is actually uncertain.

Studies on the Growth of the Barley Apex I. Interrelationships Between Primordium Formation, Apex Length, .and Spikelet Development

A detailed study has been made of the morphology of the spring.barley apex from shortly after germination to shortly before heading. The effects of 8- and 24-hr light periods and three levels of soil-moisture tension were examined with reference to the total number of primordia initiated on the main stem, the length of the apex, and the rate of spikelet development.