Observations on the Raspberry Cane Midge (Thomasiniana Theobaldi Barnes): II. “Midge Blight”, A Fungal Invasion of the Raspberry Cane Following Injury by T. Theobaldi

Seed of the Potentate variety of tomato was sown at weekly intervals for 56 weeks and weekly measurements of the diameters of every fruit were made to provide estimates of fruit volume production. Development of the plants could suitably be divided into the following periods : (a) from germination to the start of fruiting, (b) an initial lag in fruit volume production, (c) rapidly increasing production, (d) declining production and (e) arrested development, when fruit swelling virtually ceased.

The duration of the period from germination to the start of fruiting was related to day-length.

The condition of arrested fruit development occurred from approximately the shortest day to the vernal equinox in mature plants that had already attained a maximal rate of fruit volume production ; in juvenile plants it occurred, and was maintained, from approximately the autumnal equinox to the vernal equinox, i.e. when the duration of darkness exceeded that of the light. In both juvenile and mature plants the condition of arrested fruit development ceased when the duration of the light exceeded that of darkness, and a period of increasing fruit volume production ensued.

The rate of fruit volume production during this period of rapid increase was related to day-length and the relation was curvilinear. It continued to increase as long as the days continued to lengthen. When the day-length began to decline so also did the rate of production and the relation with day- length was linear.     

Gkowth and Flowering of the Tomato in Relation to Natural Light Conditions

Continuous-recording photometers were used to measure the amounts of light entering a glasshouse during certain growth periods of young tomato plants. Fresh and dry weights of the tops of the plants and the number of days between cotyledon expansion and anthesis of the first flower of the first inflorescence were related to the recorded light values as follows :

1. The relationship between log dry weight and the light-time integral was linear up to 220,000 foot candle hours, after which a marked reduction in growth occurred.

2. The departure from linearity occurred at about the same light integral even when additional nutrients were supplied to the standard volume of compost, but was delayed when a larger container was used.

3. The number of days to anthesis and the recorded light-time integrals show the following relationships : in winter, light integrals are constant (about 400,000 f.c.h.) while time is variable ; in summer, time is constant (about 40 days) while the light integrals are variable.

4. In summer, neither the reduction of the natural day-length to 9 hours nor the reduction of the light intensity to 75% normal materially influenced the number of days to anthesis.

It is concluded that in winter growth is limited by, and is therefore proportional to, the amount of available photosynthetic light, while in summer the young tomato is light-saturated and growth is limited by factors other than light.

The results indicate that the amount of photosynthetic light is the major factor determining the seasonal pattern of days to anthesis. There was no indication of any photoperiodic response.     

The effect of day length,source of light and growth regulators on growth and flowering of Clerodendrum thomsonae Balf

The formation of flower buds in Clerodendrum seems not to be affected by day length, but the development of the buds is delayed in long days. When long days were established by means of low-intensity illumination with incandescent lamps, few flowers developed and the stems elongated considerably even at a day length of 16 hours. When fluorescent lamps were used for day-length extension, short shoots with many flowers were obtained even in 24-hour days. Flower development was also delayed by gibberellic acid (GA₃), but promoted by chlormequat both in short and long days. Shoot elongation was retarded by chlormequat and promoted by GA₃.Plants obtained from commercial greenhouses varied considerably with respect to growth and flowering. By selection a clone was obtained which flowered richly on short shoots. Shoot elongation stopped when flowering began. A ‘negative’ selection gave rise to a clone which flowered sparsely and in which shoot elongation was not influenced by flowering.     

Relations Between Growth of Leaves,Fruit and Shoot of Glasshouse Tomato Plants

The weekly rates of shoot extension and total growth in leaf length of the glasshouse tomato variety Potentate increased from germination until soon after the start of ovary swelling. It is postulated that when, or soon after, the first flower primordia were initiated, an internal reaction was stimulated that eventually resulted in the cessation of the progressive increase in the rates of shoot extension and growth in leaf length. Increase in the rate of vegetative growth ceased soon after the start of ovary swelling, but this occurred even when no ovaries were allowed to swell.

The diameter of the shoot was unaffected by removal of leaves but increased when no fruits were allowed to develop. Conversely, shoot extension growth was unaffected by removal of fruit but decreased when alternate immature leaves were removed, although the removal of mature leaves had no effect on shoot extension growth.

Removal of leaves was associated with a reduction in total fruit volume and an increase in total leaf length.

Removal of immature fruit was associated with an increase in total leaf length. Removal of alternate immature fruits had little effect on total fruit . volume ; the difference between normally fruiting plants and plants from which alternate fruits had been removed was less than 0?5%.     

寒富苹果授粉花柱的荧光显微观察与自交亲和性分析

以寒富苹果为试材,进行自花和异花授粉后花朵和花序坐果率、平均种子数调查试验和荧光显微观察,结果表明,寒富苹果自花授粉的花朵坐果率高达92.8%,花序坐果率为98.3%,平均种子数为7.9粒;略低于异花授粉的96.6%、100%和9.5粒。自花授粉8 h后花粉开始萌发,花粉管能够正常生长,48 h花粉管伸入花柱中部,并在72 h后通过花柱基部,进入子房室。而异花授粉后8 h花粉管开始进入花柱,24 h花粉管伸入花柱中部,48 h花粉管穿过花柱的基部并进入子房室。     

Further Experiments on the Control of the Apple Blossom Weevil,Anthonomus Pomorum L.

The age at anthesis of tomato plants grown from weekly sowings varied throughout the year. This was related to the mean day-length from germination to anthesis, the asymptotes being an age of 40 to 50 days and a mean day-length of approximately 10 hours. Age at anthesis was also related to the total radiation received and the seasonal variation in flowering age could be explained by postulating (a) a minimal total radiation requirement for anthesis to occur and (b) a minimal age of 40 to 50 days before which anthesis could not occur. Sowings that began to flower between the autumnal and vernal equinoxes exhibited a considerable delay in attaining anthesis and the age at first flowering increased to values exceeding 110 days from sowing. The factor causing this delay was removed at approximately the vernal equinox, and a spring-like flush of flowering occurred during the month of March, with more than 20% of all the sowings beginning to flower during this one month. The data suggest that the factor responsible for this phenomenon might be light duration or it might be total radiation. It was found that the seasonal pattern of flowering exhibited a rapid increase in the weekly rate of flowering from early March to early May, followed by a progressive decline until July. From July until the following early March a low weekly rate of flowering was maintained.     

Responses of native Lupinus varius (L.) to culture conditions: effects of photoperiod and sowing time on growth and flowering characteristics

The effects of photoperiod and sowing time on growth and flowering characteristics of Lupinus varius were investigated during two growing periods to determine its responses to culture conditions as a potential native cut-flower crop. The seeds were sown in an unheated plastic greenhouse on 28 September, 28 October and 28 November under natural, 14- and 16-h day-length treatments. 14- and 16-h day-lengths were established by lengthening the natural day-lengths to 14 and 16 h with the use of night break photoperiodic lighting at 1.8–1.9 μmol m⁻² s⁻¹ in 400–700 nm. Photoperiodic lighting, in particular the 16-h day-length treatments, slightly (maximally 15 days) shortened days to flowering and increased plant height in all sowing times relative to natural photoperiods. There were no significant differences in stem and branch inflorescence diameters, in lengths of branch, in main and branch inflorescences in plants grown under natural photoperiod, and 16-h day-length treatments. The highest main inflorescence diameter, the number of branches per plant, and flower numbers on main and branch inflorescences were recorded in plants grown under natural photoperiods, whereas 14-h day-length treatments did not provide sufficient specimens to allow for the measurement of most of the characteristics studied. These findings were interpreted to indicate that L. varius behaves as a facultative long day plant. Additionally, there was a particular shortening of days to flower and growth, and flowering quality decreased linearly with delayed sowing dates under all photoperiodic treatments. The earliest and latest flowering dates were recorded for plants sown in September under 16-h day-length, and plants sown in November under natural photoperiods, respectively. Therefore, sowing in September under natural photoperiods or 16-h artificial day-length resulted in earlier flowering dates and a longer time from sowing to flowering and was consequently the best sowing time with respect to all of the characteristics considered in this study.     

Effects of inflorescence removal on the fruit set of the remaining inflorescences and development of the laterals on one year old apple (Malus domestica Borkh.) branches

Summary

Inflorescences are known to be important physiological sinks especially when they set fruit. The effect, over two successive years, of inflorescence removal on one year old wood was investigated on apple (Malus domestica Borkh.). The study was carried out on medium vigour (around 30 cm) branches of cv. Granny Smith. On one set of branches (control) the inflorescences were untreated, while on two other sets, one-third and two-thirds of inflorescences (spur leaves, bourse-shoot and flower cluster) were removed at full bloom. The first analysis investigated the fruit setting ability of remaining inflorescences. The results generally confirmed previous results on the positive correlation between the number of leaves and flowers of the inflorescence and fruit set, and also the higher fruit set on two year old wood as compared with one year old wood. On one year old wood, inflorescence removal treatments tended to increase the fruit set of inflorescences with a low number of leaves and flowers leading to a level of fruit set similar to that of inflorescences with a larger number of leaves and flowers. On two year old wood, in the following year, only the two-thirds treatment increased fruit set consistently compared with the control. A second analysis investigated the effect of inflorescence removal on lateral shoot development. It was shown that the treatments had a little effect on quantitative growth (length, diameter) of the laterals per se. On the other hand, the removal of two-thirds of the inflorescence significantly stimulated the development of fruitful inflorescences the following year. Results are discussed in relation to the local versus global physiological integration at the branch level.     

壶瓶枣花芽分化与落性枝生长发育观察

以壶瓶枣(Ziziphus jujuba Mill.cv.Hupingzao)为试材,从枣股刚萌动起到落性枝停止生长止,观察了落性枝的分化、单花分化、花序分化的形态学特征,并分析了花芽分化与落性枝生长之间的关系。结果表明,落性枝雏形分化主要在发芽前完成,在芽体中可分化完成7～10个叶片,发芽后根据树体营养状况可继续分化。刚发芽后即开始花芽分化,单花分化需经过花原基、萼片、花瓣、雄蕊、雌蕊5个分化时期,需1周左右,花芽分化有其顺序性和不可逆性。花序分化先顶花再一级花、二级花顺序进行。花芽分化随着落性枝的生长进行,落性枝基部1～2节和顶部1～5节的花芽分化不完全,中部花多而质好,开花后落性枝生长停止,到最后一片叶展开后先端部分逐渐枯萎脱落。     

小型四倍体西瓜低稔性胚胎发育研究

以小型西瓜自交系049(2X)和049(4X)为材料,对二、四倍体花粉萌发、花粉管生长及受精后的胚胎发育进行观察分析。分析结果表明,二倍体西瓜花粉萌发率较高,达96.3%,花粉管生长整齐一致,生长速度快,授粉后9 h进入子房;四倍体花粉粒形态异常的较多,花粉萌发率较低,仅为63.7%,花粉管生长易扭曲、折叠、盘绕,生长速度慢,授粉后12 h才进入子房。在胚胎发育过程中,小型二倍体西瓜胚胎发育速度快,胚体退化现象少;四倍体西瓜胚胎发育速度慢,从原胚到鱼雷胚期间容易出现因胚乳游离核或胚乳细胞解体而导致胚败育。可见四倍体西瓜正常花粉减少、花粉管生长异常及胚体退化是造成四倍体低稔性的重要原因。     

Crop production in recirculating nutrient solution

The development of a low capital cost technique for crop production in recirculating nutrient solution is described with special reference to greenhouse tomato production. Tomato trials in heated glasshouses are reported and attention is drawn to the decline in root growth which began in late April and ceased in early June. It is suggested that this “May check” may be related to time of year and not to plant age.     

Cell division and expansion in the cucumber fruit

The contributions of different fruit parts to the growth of a parthenocarpic cucumber fruit were analysed throughout fruit development. Growth in length and circumference were measured along the fruit. Cell size was measured at several places in the pericarp of the fruit during its development and the contribution of cell division and expansion to the growth of the fruit was quantified. All parts along the fruit expanded in length and thickness at approximately the same rate, except for the fruit ends, where the growth rate slowed down sooner than in the middle part. The increase in thickness of the fruit was the result of a constant increase in thickness of placenta and pericarp throughout development of the fruit. No specific expansion zones were observed. Cells expanded continuously throughout ovary and fruit development. Cell division, however, was restricted to the first part of the growing period. Cell size decreased from the peduncle end towards the blossom end of the fruit. Along the pericarp radius there was also a gradient in cell size with the largest cells in the middle of the pericarp. During fruit development the zone with the largest cells shifted a little towards the epidermis. Although there were marked differences in cell size within a fruit, all cells continuously expanded and cell division ceased in the whole fruit at approximately the same time.     

唐菖蒲花序发育特性的研究

唐菖蒲６个切花品种花序生长发育与叶数的增加呈特定的关系,在２～３叶期花序分化开始后,首先是小花数迅速增加,至５叶期停止增加,而花茎开始迅速伸长生长,单个小花生长发育加快,同时已分化的小花从花序顶端开始发生不同程度的败育,导致切花的每穗花数降低。     

Effect of light conditions on the development of the inflorescence in tomato

By growing tomato plants (Lycopersicon esculentum Mill.) in 4 different light regimes (2 photoperiods — 8 and 16 h — combined with 2 light intensities — 9,000 and 18,000 ergs cm^?2 s^?1, it was shown that increasing light integrals hastened flower initiation, greatly promoted the development of the inflorescence and increased the rates of leaf production and the growth of the stem. In similar light integrals, flower initiation was earlier and inflorescence development far better in short photoperiods than in long ones; the rates of leaf production were almost the same and stem growth was greater in long days.Transfer experiments from favourable to insufficient light conditions and inverse transfers at different times during the life of the plant indicated that light conditions were critical at the time of, and after, the macroscopic appearance of the inflorescence. At that stage, a transfer to low light conditions for 10 days induced complete abortion of the truss in our growth conditions. The effect of a transfer from insufficient to favourable light conditions was slower since at least 15 days in these latter conditions were required in order to achieve the development of the inflorescence.     

An investigation of the relationship between reproductive growth and yield loss in hazelnut

This study was carried out in Samsun during a 2-year period to examine the relationship between reproductive and yield loses in the ‘Tombul’ and ‘Palaz’ hazelnut cultivars. In hazelnuts, male and female flowering occur in winter after the breaking of inflorescence dormancy. In the present study, growth of the ovary of the hazelnut started in April and continued until mid-June. At the time of flowering the ovary did not form. The ovule growth showed a rapid increase at the end of June. Change in the diameter of the ovary and ovule with time showed a simple sigmoid growth curve. Fertilization occurred during the period between mid-May and the beginning of June, namely, 3.5–5 months after pollination. At this time, the diameter of the nut was 9.54 mm. Twin kernel was not observed. The ratio of double kernels was close to zero. The time period from fertilization to harvest was 89 days in 1997 and 96 days in 1998 for Tombul cultivar. For the Palaz, this period was 84 days in 1997 and 86 days in 1998. The rate of pistillate flower clusters which dropped in April–May was more than those dropped in June–August.     

Contributions of short- and long-shoots to yield of ‘Kerman’ pistachio (Pistacia vera L.)

The canopy of a mature ‘Kerman’ pistachio (Pistacia vera L.) tree is composed of two types of shoots: short-shoots composed entirely of preformed nodes, and long-shoots composed of both preformed and neoformed nodes. Since the production of these two types of shoots is known to be related to rootstock and rootstock influences yield of pistachio the relationship of these two types of shoots to yield was investigated during two cropping years. Individual short-shoots produced significantly less yield and had fewer fruit clusters per shoot compared with long-shoots, but collectively produced 55–60% of the total yield. Long-shoots positively affected yield components in one year, but had no effect in the other year. Whether the differences in the one year were due to canopy position and light interception or differences in the carbohydrate allocation within the two types of shoots could not be determined from the current data. Long-shoots initiated more inflorescence buds, although inflorescence bud formation was restricted to the preformed growth and only the 3–4 earliest neoformed nodes. However, when expressed as a percentage, long-shoots retained a lower percentage of initiated inflorescence buds, compared with short-shoots. Regardless of shoot type, less than half of the retained inflorescence buds produced mature fruit clusters. Thus, inflorescence bud retention, a previously hypothesized mechanism of pistachio alternate bearing, may not be the primary limiting factor to yield in pistachio.     

Studies on the post-initiation development of flower buds of tomato (Lycopersicon Esculentum)

The application of high temperature (ca. 70° F., 21° C.) to tomato plants for varying periods prior to first anthesis showed that:

1. Inflorescence abortion occurred when high temperature (and low light) was applied in the late stages of development of the inflorescence. Similar treatment in the early stages, up to the time when the first cluster of buds could be seen by the naked eye, did not induce abortion.

2. In low light conditions, equivalent to those occurring naturally at mid-winter, an initial period of high temperature (70° F.) followed by low (60° F., 15–5° C.) induced a greater flowering capacity than constant low temperature.

3. The beneficial effects on flower development resulting from early high temperature treatment were greatest when the day temperature was high, though some benefit also resulted from a high night temperature. The effects were evident only with early (October) sown plants. There was no apparent adverse effect on flower development of high temperature applied up to the “visible bud” stage (2,250 kilolux hours).     

Effect of temperature,daylength and light intensity on growth and development of Dipladenia sanderi Hemsl. ‘Rosea’

Dipladenia sanderi Hemsl. ‘Rosea’ (syn.: Mandevilla sanderi (Hemsl.) Woodson ‘Rosea’) was grown in a glasshouse at 12, 15, 18 and 21°C, daylengths of 8 or 20 h, natural daylight, and natural daylight supplemented with cool-white fluorescent lamps (10 W m^?2).Time from propagation to unfolded flower decreased with increasing temperature, and at 12°C there were relatively few flowers in the inflorescences. The time to flower opening was not influenced by daylength, but with 20 h there were more buds in the first developed inflorescence and the petals were larger than with 8 h. In addition, the vegetative growth was favoured by 20 h. Supplementary lighting shortened the developmental time to unfolded flower, but the flowers were smaller than in natural light only.The growth and development varied according to the time of year. Dipladenia was able to bloom all year round, except in January and February. The low light intensity in November and December probably made it impossible for the buds to develop into flowers in January and February.     

剪叶对茭白肉质茎膨大的影响

以 1个单季茭和 1个双季茭茭白品种为试材 ,在肉质茎开始膨大时进行不同程度的剪叶处理 ,结果表明 :各处理在开始膨大后最初几天内干、鲜质量差异不明显 ;剪去叶片对肉质茎膨大影响不大 ,但切除叶鞘后 ,肉质茎膨大初期以后的干、鲜质量显著下降 ;整株剪叶比单茎剪叶处理对肉质茎膨大的影响大 ,剪去叶片与切除叶鞘、叶片表现相似。由此认为 ,茭白肉质茎膨大所需养分主要依靠短缩茎和叶鞘在肉质茎膨大前的积累 ,肉质茎膨大过程中植株茎蘖间存在养分交流 ,品种间在膨大速率上有一定差异。     

Photoperiodic reaction of sexual and asexual reproduction in Fragaria chiloensis L. CHI-24-1 plants grown at various temperatures

Floral initiation of a wild strawberry strain, Fragaria chiloensis CHI-24-1, is strongly induced by a 24 h day-length (DL) treatment for 40 days consisting of natural daylight and continuous lighting at night by an incandescent lamp. To use the characteristics of floral initiation in CHI-24-1 as a genetic resource for breeding of cultivated strawberries, the photoperiodic reactions of sexual and asexual reproductive growth under various temperature conditions should be clarified. For that purpose, we examined: (1) floral initiation, inflorescence emergence and runner production seasons of CHI-24-1 plants grown under natural climatic conditions in an open field at the Faculty of Agriculture, Kagawa University and (2) the effects of various DLs and temperatures on floral initiation and runner production of CHI-24-1 plants. When the CHI-24-1 plants were grown under natural conditions, the floral initiation, inflorescence emergence and runner production were observed, respectively, in late autumn, spring, and from spring to autumn. Floral initiation of CHI-24-1 plants was induced strongly by 24 h DL at mean temperatures greater than 20 °C. The maximum floral initiation rates were 90% in the parent plant and 94% in the daughter plants, which were linked by runners to the parent plant. The floral initiation of the daughter plants occurred under 20, 22, and 23 h DL at mean temperatures greater than 20 °C, but not for the parent plants. Floral initiation was induced in 100% of the parent plants by the 8 h DL and the lowest mean-temperature conditions. Results of those experiments indicated that CHI-24-1 was an absolute long day plant having critical DL of about 20 h at mean temperatures greater than 20 °C, even though it was a June-bearing strawberry plant. In addition, CHI-24-1 was a facultative short-day plant at mean temperatures of less than 15 °C.