The effect of temperature on axillary bud-break of hybrid tea-rose seedlings

The effect of temperature on the time of bud-break and on the number of sprouted buds was studied in F₁-seedling populations of glasshouse rose cultivars, which were grown in full daylight at 4 controlled temperatures (10, 14, 18 or 22°C). At lower temperatures, anthesis and bud-break occurred later. Relative to anthesis, bud-break occurred earlier with lower temperatures. Temperature had no effect on the percentage of buds sprouted, on the axillary position at which sprouting occurred, or on the order of sprouting. However, axillary buds in the central part of the seedling shoot were strongly inhibited; lower and upper buds sprouted almost simultaneously. Selection for time of sprouting and number of sprouted buds may be carried out at any temperature in the range studied.Differences in axillary bud-break between seedlings and cultivars, and the consequences for selection, are discussed.     

Anatomy of flower differentiation and abortion,in relation to the growth and development of hybrid tea-rose seedlings

From germination until anthesis or flower bud abortion, seedlings from ‘Sonia’ × ‘Hadley’ were grown in both a greenhouse (full daylight, 20° C) and a growth room (8 Wm^?2, 8 h, 20°C) of the IVT-phytotron. Plastochron was an external indication of the stage of flower differentiation. Flower differentiation in flowering and aborting seedlings ran parallel up to petal-segregation. Flower differentiation in aborting seedlings did not proceed beyond stamen formation. Early abortion, which also caused absence of the upper leaf, occurred without, later abortion with, an abscission zone in the flowerstalk.     

Effects of temperature on growth and development of hybrid Tea-rose seedlings

Hybrid Tea-rose seedlings were grown, from germination to first flowering, at 6 constant temperatures between 10 and 26°C in greenhouses of our phytotron. All seedlings flowered regardless of temperature. When temperature increased, the juvenile period, the number of days to first flowering, the length of the leaved part of the shoot, the length of the flower stalk, the fresh weight of the shoot and of the root decreased; leaf number was not affected.     

The influence of far-red light on the development of tomato seedlings

The influence of far-red light on the development of tomato seedlings was investigated. It was found that a deficiency of it in the incident spectrum retarded stem elongation. The quantity of far-red light in the flux did not affect the number of flowers forming on the first truss or the time of anthesis.     

Interacting effects of temperature integration and light intensity on growth and development of single-stemmed cut rose plants

Energy conservation in horticulture can be achieved by allowing temperatures to fluctuate within predefined bandwidths instead of using rigid set points for heating and ventilation. In temperature integration, plants are supposed to compensate effects of temporarily deviations of the average temperature some time later by deviations in the opposite direction. However, little is still known on the effects of integration periods exceeding 1 day. In this study, effects of temperature integration on growth and development of single-stemmed cut rose plants were determined. Pruned rose shoots were placed in climate chambers in which light levels switched daily (2 days integration period) or weekly (14 days integration period) from high light intensity (300 μmol m⁻² s⁻¹) to low light (150 μmol m⁻² s⁻¹). Temperatures were kept continuously at 20 °C (control) or changed with the light intensity (phase, high temperature at high light intensity, low temperature at low light intensity) or changed opposite to the light intensity (counter phase). Bandwidths of temperature integration were 0, 6 or 10 °C. Under these conditions, buds grew out to harvestable shoots in approximately 45 days. At both integration periods, shoot length was significantly reduced with increasing bandwidths of temperature integration. Shoot dry weights were reduced when a bandwidth of 10 °C was applied. At both integration periods, rates of photosynthesis were primarily determined by light intensity. However, in the counter phase treatments, photosynthesis rate at high light and low temperature was reduced compared to the high light condition of the control. Under these conditions, starch content increased to approximately 10%, suggesting a feedback inhibition of the rate of photosynthesis. However, this did not (yet) affect plant growth or development.     

低温弱光对西葫芦幼苗渗透调节物质的影响

以西葫芦品种早青一代为试材,研究了不同低温弱光组合及低温弱光持续时间对西葫芦幼苗渗透调节物质的影响。结果表明:可溶性蛋白质含量随低温弱光逆境程度加剧和持续时间延长持续减少;在15℃/5℃以上,弱光处理渗透调节物质游离脯氨酸、可溶性糖含量增加,但增加幅度随着弱光逆境加剧和持续时间延长而减弱;但在15℃/5℃下,弱光逆境导致游离脯氨酸、可溶性糖含量先增加后降低。     

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.     

The effect of temperature on growth and dry matter production of lychee seedlings

In lychee (Litchi chinensis Sonn.), high day/night temperatures ($\text{30}\text{25}$, $\text{25}\text{20}$, $\text{20}\text{15}\text{°}\text{C}$ compared to $\text{15}\text{10}\text{°}\text{C}$) increased stem extension, node and leaf production and plant dry weight in seedling selections of 6 cultivars (‘Bengal’, ‘Haak Yip’, ‘Kwai May’, ‘Gee Kee’, ‘Tai So’ and ‘Wai Chee’). The mean daily base temperature for shoot growth (node production) was estimated by linear correlation to be 11.0°C for the seedlings. High temperatures also increased the proportion of leaf and decreased the proportion of root in the total dry weight. There was a strong effect of cultivar on all aspects of growth, but the responses to temperature were similar.This experiment shows that temperatures in many tropical and warm sub-tropical areas where lychees are grown are too high to induce satisfactory vegetative dormancy prior to floral initiation. The assessment of lychee seedlings for low vigour in a heated glasshouse appears to be a useful technique for the initial screening of adapted genotypes (which flower and fruit under warm conditions) prior to field evaluation.     

Interactions between root-zone temperature and light levels on growth,development and photosynthesis of Lycopersicon esculentum Mill. cultivar ‘Vendor’

Six-week-old tomato plants were subjected to 5 root-zone temperatures, ranging from 12 to 36°C, and 4 light levels in a factorial design. Large increases in shoot dry weight, leaf area and fruit development resulted from soil warming to 24°C when plants were grown under high light conditions. Shoot growth and fruit weight were reduced at 24°C root temperature under low light conditions. Total plant photosynthesis, leaf area index, net assimilation rates and leaf chlorophyll content were related to plant growth and flower development for the various treatments. Our experiments have shown an interaction between root-zone temperature and light levels for greenhouse tomatoes. Soil warming caused large increases in shoot dry weight and fruit development when light was not limiting plant growth, but had deleterious effects on flowering and fruit set under shaded conditions.     

Effect of light,temperature and CO2 on the growth of Campanula isophylla stock plants and on the subsequent growth and development of their cuttings

Stock plants of Campanula isophylla Moretti were subjected to different temperature and light conditions and to various CO₂ regimes. The number and the fresh and dry weight of the cuttings produced were recorded. The after-effect of stock-plant treatment on root formation and growth of cuttings was studied.Increasing light intensity and CO₂ supply strongly promoted cutting production and increased both fresh and dry weight of the cuttings. These factors also markedly influenced root formation and root growth of the cuttings. Stock plant conditions also strongly influenced the growth and lateral shoot formation of the rooted cuttings. It is concluded that cuttings from stock plants grown under favourable light (10 Klx) and CO₂ conditions (900 v.p.m.) contain factors beneficial for root formation, growth and shoot formation. The results are discussed in relation to the carbohydrate content of the cuttings.     

枯草芽孢杆菌B67对黄瓜幼苗生长发育的影响

为明确枯草芽孢杆菌B67对黄瓜幼苗生长发育的影响,采用水培法,测定了不同浓度枯草芽孢杆菌对黄瓜苗期地上部(平均直径、茎长、干质量、鲜质量)和地下部(根长、根表面积、根体积、根平均直径、须根数、根鲜质量和干质量)生长及根冠比的影响。结果表明,20%枯草芽孢杆菌B67菌液处理2次的黄瓜幼苗长势良好,处理后21 d平均直径4.88 mm,株高11.15 cm,根长21.65 cm,根冠比0.94,与各处理结果差异显著。不同浓度B67菌液对黄瓜苗期促生作用呈正态分布,浓度为20%枯草芽孢杆菌B67菌液,施药2次(间隔期7 d)促生效果最佳,为指导B67菌液在肥料中添加及创制新型农药提供了理论依据。     

小麦秸秆复合基质对番茄幼苗生长发育的影响

为了充分利用农业废弃物小麦秸秆,进行草炭替代性育苗基质原料的研发,实现农业资源循环化利用和生态可持续发展。以番茄‘毛粉802’为材料,通过小麦秸秆腐熟物、草炭、蛭石和珍珠岩4种基质原料及1种生物菌肥进行不同体积配比处理,研究不同配比的小麦秸秆复合基质对番茄幼苗生长指标、叶片色素及荧光指标、幼苗叶片理化性质指标、基质生物指标和理化性质的影响,探究适合番茄幼苗生长的小麦秸秆复合育苗基质配方。利用灰色关联法对19项指标进行综合分析。结果表明,V腐熟小麦秸秆∶V蛭石∶V珍珠岩∶V生物菌肥=6∶2.5∶1∶0.5番茄幼苗表现最好,而番茄幼苗在纯小麦秸秆腐熟物上的生长量远远低于其他处理,番茄幼苗的表现最差。     

愈合期不同温度和光照处理对甜瓜嫁接苗质量的影响

温度和光照是影响嫁接成活的重要环境因子,目前对甜瓜嫁接苗愈合过程中温度和光照管理的具体参数尚不明晰。笔者将嫁接愈合期分为0～3 d、4～6 d、7～8 d等3个阶段,设置了6种温度和光照组合处理,研究其对甜瓜嫁接苗成活、生长和种苗品质的影响。结果表明,在嫁接后0～3 d温度为28/23℃,4～6 d为25/20℃,7～8 d为23/18℃,光照处理0～3 d为75μmol·m~(-2)·s~(-1),4～6 d为150μmol·m~(-2)·s~(-1),7～8 d为225μmol·m~(-2)·s~(-1)时甜瓜嫁接苗成活率高且种苗品质好,是适宜甜瓜嫁接苗愈合管理的温度和光照参数。     

叶面喷施蔗糖对弱光胁迫下南瓜幼苗生长和光合特性的影响

为探究外源蔗糖对弱光胁迫下南瓜幼苗生长和光合特性的影响,以蜜本南瓜为材料,设置4个处理:正常光照(300μmol·m-2·s-1)下叶面喷施清水(CK),弱光(150μmol·m-2·s-1)下喷施清水(T0)、1％的蔗糖(T1)和2％的蔗糖(T2).结果表明,与正常光照相比,弱光显著降低了南瓜幼苗的株高、茎粗、生物量...     

Effects of low temperature storage on growth and transplant quality of non-grafted and grafted cantaloupe-type muskmelon seedlings

Grafting is a unique horticultural technology that allows the grower to select an alternate, compatible root system with natural disease resistance for their desired crop. Short-term storage of grafted seedlings under low temperature may extend the production window of grafted seedlings, reduce the labor input and increase production of grafted seedlings with a small propagation capacity. To evaluate the low temperature storage conditions, Cucumis melo ‘Olympic Gold’ seedlings were grafted onto Cucurbita maxima x Cucurbita moschata ‘Tetsukabuto’ rootstock and stored for a period of 2 or 4 weeks at 9, 12, or 15 °C under 12 μmol m⁻² s⁻¹ photosynthetic photon flux (PPF). The study demonstrated that grafted seedlings could be stored at 12 °C for 4 weeks without significant dry mass accumulation or effects on post-storage growth and development. Grafted seedlings stored at 15 °C for 4 weeks had a significant increase in dry mass and stem elongation; this was not observed for the non-grafted seedlings stored under the same conditions, suggesting that the rootstock enhanced the scion growth at lower temperatures than optimal for muskmelon. Storing muskmelon seedlings at 9 °C caused chilling damage but the damage was pronounced for non-grafted seedlings than grafted seedlings. ‘Tetsukabuto’ rootstock, an interspecific squash, presumably has a chilling tolerance and increased the storability of muskmelon seedlings. Further optimization is needed but there is potential for using this technique as a tool for mass production of grafted muskmelon seedlings.     

Modeling plant morphology and development of petunia in response to temperature and photosynthetic daily light integral

The effects of mean daily temperature (MDT) and mean photosynthetic daily light integral (MDLI) on flowering during the finish stage of two petunia (Petunia × hybrida) cultivars were quantified. Petunia ‘Easy Wave Coral Reef’ and ‘Wave Purple’ were grown in glass-glazed greenhouses at 14–23 °C or 14–26 °C and under 4–19 mol m⁻² d⁻¹ with a 16-h photoperiod. The flower developmental rate was predicted using a model that included a linear MDT function with a base temperature multiplied by an exponential MDLI saturation function. The flower developmental rate increased and time to flower decreased as MDT increased within the temperature range studied. For example, under a MDLI of 12 mol m⁻² d⁻¹, as MDT increased from 14 to 23 °C, time to flower of ‘Easy Wave Coral Reef’ and ‘Wave Purple’ decreased from 51 to 22 d and 62 to 30 d, respectively. Flower developmental rate increased as MDLI increased until saturation at 14.1–14.4 mol m⁻² d⁻¹. Nonlinear models were generated for effects of MDT and MDLI on flower bud number and plant height at flowering. The number of flower buds at flowering increased as MDT decreased and MDLI increased. For example, at an MDT of 14 °C with 18 mol m⁻² d⁻¹, plants had 2.5–2.9 times more flower buds than those grown at 23 °C and 4 mol m⁻² d⁻¹. Models were validated with an independent data set, and the predicted time to flower, flower bud number, and plant height were within ±7 d, ±20 flowers, and ±4 cm, respectively, for 96–100%, 62–87%, and 93–100% of the observations, respectively. The models could be used during greenhouse crop production to improve scheduling and predict plant quality of these petunia cultivars.     

Effect of temperature on photosynthesis of lettuce adapted to different light and temperature conditions

Gas exchange of lettuce plants, pre-grown in growth chambers at different irradiances (18, 37, 70 W m^?2) and temperatures (6, 14, 22°C) were measured in the range of 2–22°C. In weak light (18 W m^?2) there was no increase in CO₂ uptake above 2°C, and even in 70 W m^?2 the highest rates were obtained at about 10°C only. The response of net photosynthesis of lettuce to temperature is diminished as a result of morphological plant adaptations, i.e. specific leaf area or top-to-root weight ratio. The temperature optimum for dry-matter production is much higher than that for CO₂ uptake. Therefore, photosynthesis is an unsuitable criterion for temperature control in greenhouses.     

Bulbing responses of two cultivars of red tropical onions to photoperiod,light integral and temperature under controlled growth conditions

Summary

The effects of photoperiod, light intensity and temperature on bulb formation and bulb structure of two tropical onion cultivars were investigated. From an initial experiment it was observed that the number of true scales and sheath scales differed significantly between the cultivars ‘Red Creole’ and ‘Agrifound Dark Red’. When these two cultivars were given 11, 12 and 13 h photoperiod treatments, it was found that both cultivars needed at least 12 h photoperiod for bulb formation. Modify the R/FR ratio from 1.22 to 1.16 in the final hour of the 11 h light period did not induce bulbing. The 13 h photoperiod increased the number of true scales and decreased the number of sheath scales compared with the 12 h photoperiod in both cultivars but total scale + leaf sheath numbers remained nearly constant. When onion plants were grown under 0%, 25%, 50% and 75% shading treatments, (12 h photoperiod), only plants receiving 0% and 25% shading bulbed. Low light intensity decreased the number of true scales and increased the number of sheath scales. Four temperature regimes were compared in a growth room experiment. Plants under the 29°348C treatment bulbed within two weeks and matured within six weeks. However, plants receiving the 25°308C treatment delayed bulb initiation more than those plants receiving 17°228C and 21°268C treatments. At the lowest temperature, bigger bulbs with thick necks were produced. This may be due to changes in bulb structure since at low temperature, the number of sheath scales was increased, however the number of true scales remained relatively constant in both cultivars. Dormant leaf initials decreased with decreasing temperature while the number of secondary meristems significantly increased. The results suggest that ‘Red Creole’ was more responsive to shorter photoperiods, bulbing earlier than ‘Agrifound Dark Red’. There was no significant difference in time to bulbing in response to temperature between the two cultivars if measured by bulbing ratio however there were differences in bulb structure which suggested that ‘Red Creole’ bulbed earlier. These effects may be due to the breeding histories of the two cultivars. It is suggested that studying bulb structure may provide a useful method of interpreting onion bulbing responses.     

不同红蓝LED组合光源对西瓜幼苗生长和生理参数的影响

西瓜是一种重要的园艺作物,种苗易徒长。以荧光灯为对照(光照强度为150μmol·m-2·s-1),探讨了相同光照强度下,不同红光蓝光配比(R/B)LED组合光源(7∶1、7∶2、7∶3)对西瓜幼苗生长和生理参数的影响。结果表明,红蓝LED组合光源下西瓜幼苗茎粗度、鲜质量、干质量、壮苗指数均有所增加,其中在R/B=7∶3下表现尤为突出。生理数据表明,较高的叶绿素和可溶性糖含量,以及较大的叶片栅栏组织厚度、气孔密度、气孔开张度和光合速率,是LED组合光源R/B=7∶3处理提高种苗质量的重要原因。     

菌根真菌与接种时期对梨幼苗生长的影响

【目的】梨树是受菌根影响的果树之一,试验筛选出对川梨侵染效应的最佳接种时期和菌根依赖性较高的菌根真菌,研究接种菌根真菌对梨根系活力及发育的影响。【方法】试验采用川梨(Pyrus pashia Buch.-Ham.)种子为材料,盆栽条件下,分别在萌芽期、幼苗3叶期、5叶期和7叶期,接种丛枝菌根真菌根内球囊霉Glomus intraradices(GI)、摩西球囊霉Glomus mosseae(GM)和地表球囊霉Glomus versiforme(GV)。【结果】试验所采用的3种丛枝菌根真菌均能有效地侵染川梨实生苗,接种GI的菌根侵染率显著高于接种GM和GV,菌根的形成对根系最长侧根长、一级新根数量和根体积都有明显提高,最大分别提高了16.3%、6.0%和13.9%,接种菌根真菌显著地提高川梨根系活力,增加根可溶性蛋白含量。【结论】接种GI的菌根效应最佳,是川梨菌根依赖性较高的菌根真菌,幼苗5叶期接种的菌根侵染效应显著高于其他接种时期,为菌根化苗木繁育技术提供技术依据。