The effect of day and night temperatures on the growth,development and yield of glasshouse cucumbers

The responses of January-sown cucumber cvs Farbio and Sandra to day and night temperature during the early post-planting stage (late February to mid-April) were examined in a glasshouse experiment. Three day temperatures (15°, 20° and 25°C) were combined factorially with three night temperatures (10°, 15° and 20°C). Comparisons were also made between two temperature regimes (21°C day: 19°C night and 24°C day: 17°C night) applied during the pre-planting stage (late January to late February) and between two mainstem cropping methods (restriction or retention of mainstem fruits). In the pre-planting stage the 24°C day: 17°C night temperature combination produced plants which were taller, heavier and leafier than those grown at 21°C day: 19°C night. During the first 12 weeks of harvesting the larger plants produced significantly more fruit and higher gross monetary returns than did their smaller counterparts. The difference then diminished and after 20 weeks of harvesting plants from the two pre-planting temperature treatments had produced similar weights of marketable fruit of equivalent value. In the early post-planting period increases in total leaf area and stem length were closely correlated with 24-h mean temperature. Earliness (first harvest) and total weight of fruit after four weeks of harvesting were also linearly related to mean post-planting temperature. Raising the 24-h mean air temperature (within the range 15.2° to 22.6°C) by 1°C during the early post-planting stage increased early (4 week) yield by 0.82 kg m^-2 and total (20 week) yield by 1.17 kg m^-2. There was no effect of day/night temperature amplitude. After 20 weeks of harvest, gross monetary returns and profitability were generally highest when mean temperature in the early post-planting period was high and fell progressively with reduced mean temperature. Restricting stem fruits to oné per leaf node produced no significant difference in either the yield or quality of fruit from plants of any of the temperature treatments. The results are discussed from physiological and practical viewpoints and a cost-benefit comparison of temperature treatments is presented.     

Temperature and daylength influences on the growth and germination of sweet basil and oregano

Oregano and sweet basil were grown in phytotron cabinets at 18/12°, 24/12° and 30/12°C (day/night) in either 10-or 16-h photoperiods. Only temperature had a positive influence on plant height in both species. The fresh yield was significantly influenced by temperature and daylength in all the three harvests examined for both species. The correlation between these results and field behaviour in different regions is discussed. The optimum temperature for the germination of oregano was a day/night regime of 24/19°C; sweet basil was less sensitive and germinated well at temperature regimes between 18/13° and 30/25°C.     

The effects of day and night temperature on Chrysanthemum morifolium: investigating the safe limits for temperature integration

Summary

The impact of day and night temperatures on pot chrysanthemum (cultivars ‘Covington’ and ‘Irvine’) was assessed by exposing cuttings, stuck in weeks 39, 44, and 49, to different temperature regimes in short-days. Glasshouse heating set-points of 12°, 15°, 18°, and 21°C, were used during the day, with venting at 2°C above these set-points. Night temperatures were then automatically manipulated to ensure that all of the treatments achieved similar mean diurnal temperatures. Plants were grown according to commercial practice and the experiment was repeated over 2 years. Increasing the day temperature from approx. 19°C to 21°C, and compensating by reducing the night temperature, did not have a significant impact on flowering time, although plant height was increased. This suggests that a temperature integration strategy which involves higher vent temperatures, and exploiting solar gain to give higher than normal day temperatures, should have minimal impact on crop scheduling. However, lowering the day-time temperature to approx. 16°C, and compensating with a warmer night, delayed flowering by up to 2 weeks. Therefore, a strategy whereby, in Winter, more heat is added at night under a thermally-efficient blackout screen may result in flowering delays. Transfers between the temperature regimes showed that the flowering delays were proportional to the amount of time spent in a low day-time temperature regime. Plants flowered at the same time, irrespective of whether they were transferred on a 1-, 2-, or 4-week cycle.     

The effects of day and night humidity on yield and quality of glasshouse cucumbers

Summary

The effects of different day and night humidity levels on autumn- and spring-grown cucumbers were examined in four glasshouse experiments. A high or low humidity during the day was combined with either a high or low humidity during the night to give four treatment combinations. The vapour pressure deficits achieved, over the total period, varied from 0.57 to 0.91 kPa by day, from 0.26 to 0.66 kPa by night, and the 24-h average varied from 0.43 to 0.75 kPa. Temperature differences between the treatments were less than 0.6°C in each experiment. Vegetative growth was enhanced by either high day or night humidity but early yield was not related to either day, night, or 24-h average humidity. A significant negative correlation was found between vapour pressure deficit by day and final total yield in all but one experiment. Fruit quality, expressed as fruit colour, was reduced by a high 24-h average humidity. Calcium deficiency in leaves was correlated with 24-h average humidity. From the viewpoint of production, the best control procedure is to maintain a high humidity during the day but to avoid high 24-h average humidity levels if good fruit quality is to be obtained.     

亚低温对温室黄瓜生长发育的影响

以全雌性黄瓜戴多星为试材,研究了适温(25℃/18℃,昼/夜)和亚低温(21℃/15℃,昼/夜)条件下黄瓜植株高度、叶面积、光合强度和叶绿素含量(SPAD值),以及根、茎、叶和果实的鲜质量与干质量以及总干物质含量的差异。结果表明,黄瓜叶片SPAD值、光合强度、叶面积、株高、茎和叶的鲜、干质量均是亚低温处理低于适温处理;亚低温条件下果实数和果实鲜、干质量高于适温处理;在亚低温条件下植株总干质量与适温处理无差异,果实干质量增加是因为亚低温条件下叶干质量的明显减少所致。     

Temperature integration of Hederahelix L.: Quality aspects and growth response

Reducing energy use in greenhouses contributes to the profitability of horticulture. Important energy savings can be realized through the use of temperature integration. However, such a greenhouse heating strategy is only acceptable for commercial purposes if there are no adverse effects on plant growth and quality. During this 3-month study, Hedera helix ‘Green Ripple’ and H. helix ‘Shamrock’ were subjected to a day/night temperature regime of 20/20 °C (control) and two treatments with temperature integration over 24 h and 4 d, respectively, based on a DIF of 13.5 °C, maintaining the average temperature at the same level of the control. Temperature treatments resulted in a promotion of stem elongation. After 3 months, shoot length rose up to maximum 37.3% when temperature integration was applied. However, temperature integration reduced total dry weight and particularly root dry weight was negatively affected. In addition, assessments of relative growth rate, shoot extension rate, specific leaf area, total leaf area and pigment concentrations were performed and it was concluded that dynamic temperature regimes with longer integration periods support commercial production of English ivy.     

Effects of far-red light/temperature DIF and far-red light/temperature pulse combinations on height of lily hybrids

Summary

Potted bulbs of ‘Nellie White’, ‘Sunray’ and ‘Stargazer’ representing three lily hybrids [Easter (Lilium longiflorum Thunb.), Asiatic and Oriental, respectively], were forced in a glass greenhouse under three lighting regimes namely, 8.h photoperiod (8 PP) by using blackout between 1600 hours and 0800 hours to eliminate twilight; 8 PP extended with 1.h of low intensity far-red radiation (9 PP) at the beginning of the dark period; or ambient. All three lighting regimes were in a greenhouse with either a +5°C or a -5°c DIF (= T_day ±T night ) regime, while maintaining the same 24.h temperature. In a second experiment, two cultivars of each of the three lily hybrids were also grown under the same three lighting regimes with a constant day/night temperature but with either a 15°cor 25°c pulse for 3.h from 1500–1800.hours to coincide with the far-red supplementation for 9 PP. Both experiments were done during the winter and repeated the following year. Within each DIF treatment, plants which received light containing far-red at the end and start of the day (ambient) or beginning of night (9 PP) were taller than those under short day (8 PP). Plants grown under either 8 PP or ambient were taller under +DIF than under -DIF, except when 8 PP was extended with 1.h of far-red, in which case plant height was the same for either DIF. ‘Nellie White’ reacted the strongest to far-red as well as to DIF followed by ‘Sunray’ and then ‘Stargazer’. For ‘Nellie White’, the stem dry weight was increased by far-red radiation at the beginning of the dark period compared with short day or ambient, while the opposite was found for the leaf and bulb dry weights. However, total dry weight of plant was not affected by either DIF or lighting treatment. In the second experiment, plant height was not significantly affected by an end of day temperature pulse of -5°c for either the 9 PP or ambient regimes compared with a +5°c pulse.     

Effects of day and night humidity on yield and fruit quality of glasshouse eggplant (Solarium melongena L.)

A spring and an autumn crop of eggplant (Solanum melongena) were grown under natural light conditions in a glasshouse at different day and night humidities. A high or low humidity by day was combined with either a high or low humidity by night. Vapour pressure deficits (VPD) achieved over the period in which the treatments were applied ranged from 0.44 to 1.18 kPa by day, from 0.24 to 0.91 kPa by night, with a 24 h mean from 0.34 to 0.99 kPa. The rate of plant development was unaffected by humidity. Fruit yields were reduced by continuously low VPD compared with the other treatments. The yield reduction could be attributed to fewer fruits being picked. Mean fruit weight was higher at high humidity by day. Continuously high VPD increased calyx withering, low VPD had no detrimental quality effects but promoted the incidence of Botrytis cinerea.     

Apple Rootstock Studies: Thirty-Five Years’ Results with Cox’s orange Pippin on Clonal Rootstocks

With the aim of obtaining information about light and temperature relationships during the early weeks of growth of young tomato plants, measurements of the weekly dry weight increments were made with plants up to six weeks old. Growth took place in natural light conditions during a number of winter periods (October to March). The daily light-time integrals (foot candle hours) were recorded throughout the investigation. In three experiments, each extending over a whole winter period, plants were grown at one-day temperature, but at three levels of night temperature, namely (a) 4° F. lower than the day, (6) equal with the day, and (c) 4° F. higher than the day. The day temperature was 6o° F. (15 ? 5° C.), 64° F. (68°C.) and 68°F. (20°C.) respectively for the three experiments. The results are summarized as follows :

1. With each day temperature, growth rates were lowest when night temperature was lower than the day.

2. Comparison of the effects of the constant temperature regimes with the high night temperature regimes showed that with the day temperature at 60° F. the growth rate was generally higher when the night temperature was high. With higher day temperatures, however, this was not the case.

3. There was little evidence that over this temperature range the temperature inducing maximum growth was related either to the light conditions or to the age of the plant.

4. The response to night temperature was small by comparison with response to that of the day.

5. The results suggest that in winter highest growth rates will be achieved if the night temperature is not lower than 64° F. and the day not lower than 68° F.

The results of an experiment designed to evaluate the separate effects of day and night temperatures showed that, over the temperature range 6o° F. to 68° F., dry weight increased with the night temperature. However, a much larger increase resulted with a comparable temperature rise during the day. Stem length was unaffected by the level of the night temperature but increased markedly with the day temperature.

The periods from pricking-out to both initiation and anthesis of the first two inflorescences were recorded for plants growing at 6o° F., 64° F. and 68° F. The temperature effect on the period to initiation was small. The inverse relationship between temperature and the period to anthesis was especially marked in low light conditions.

The value of adjusting both the day and night temperatures in accordance with the day-to-day fluctuations of the natural light was assessed by comparison with other temperature regimes having the same mean over each 24 hours. In general, flowering and fruiting was earliest when the day and night temperatures were equal. No evidence was found to justify the technique of adjusting the temperature in accordance with the natural light.     

Light-Modulated Temperature Control and the Response of Greenhouse Tomatoes to Different CO2 Regimes

A light-modulated greenhouse controller that varied the air temperature with incoming solar radiation was used in an experiment to compare the response of Craigella, Eurocross B and J172 tomatoes from first anthesis to the end of fruit harvesting to light-modulated and steady day-time air temperature regimes at CO₂ concentrations of 600 and 1200 volumes per million.

The yield of marketable fruit obtained from the light-modulated temperature regime was on average 26% higher after 6 weeks of picking and 9% higher after 22 weeks of picking than that from the steady temperature treatment. An increase in CO₂ concentration from 600 to 1200 vpm resulted in overall increases of 15% and 8% in the early and final yields of ripe marketable fruit respectively. Tomatoes grown under a light-modulated temperature regime reached the half-harvest date on average 5 days ahead of those grown in a steady temperature regime. The difference in earliness of cropping resulting from CO₂ enrichment to 1200 instead of 600 vpm was 3 days. J172 was the most successful cultivar judged by marketable yield and estimated gross monetary returns.     

日光温室温光条件对番茄营养生长与果实膨大的影响

通过对早春日光温室番茄营养生长期和果实膨大期的光照和温度条件以及番茄生长状况的动态观测,研究了日光温室温光条件对番茄生长和果实膨大的影响。结果表明：在日光温室栽培的番茄营养生长期（3 月中旬）,日均气温、夜间平均温度和浅层地温能有效反映番茄叶面积、茎粗和株高增长的动态变化,光辐射量和昼夜平均温差对叶面积、茎粗和株高的增长影响不大。在番茄果实膨大期（4 月中旬）,日均气温、见光时段小时积温和光辐射量与果实膨大均呈极显著正相关;茎粗、叶面积与果实膨大呈极显著正相关,印证了果实膨大期源-库关系的建立。     

苗期夜间低温对番茄叶片气孔开张度日变化及叶片超微结构的影响

以15℃夜温为对照,研究了6℃夜间低温对番茄叶片气孔开张度日变化及叶片结构的影响。结果表明:处理7d时,处理植株叶片气孔器大小和叶面积显著小于对照,气孔密度显著大于对照。表皮厚度极显著大于对照。叶片厚度大于对照,但与对照差异不显著。处理植株番茄叶片气孔张开程度一天中皆小于对照,气孔张开率上午与对照差异不显著,14:00显著小于对照。16:00极显著小于对照;恢复7d时,夜低温处理番茄叶片气孔器显著大于对照。气孔密度、每叶气孔数及单叶叶面积、气孔张开率皆小于对照,叶片气孔开口程度、叶片表皮厚度及厚度大于对照,但差异都不显著;夜间低温处理后叶片栅栏组织显得更紧密,恢复7d后无显著差异。     

Flushing and Leaf Growth of Cacao Under Controlled Temperature Conditions

Young clonal cacao trees have been grown for nine months in controlled- environment rooms at 74° F.,80°F. or 86° F. (23·3° C., 26·7° C., or 30·0° C.), or at one of these temperatures during the day and another during the night.

No specific temperature requirements for leaf flushing, which occurred in all the treatments, were found. Flushing was considerably greater at the higher temperatures, partly as a result of the loss of apical dominance, and was especially sensitive to day temperature.

The number of expanded leaves per flush and mean area per leaf increased with a decrease in day or night temperature, as did the duration of the leaves on the trees. The biggest net leaf area increases were made by plants given a day at 80° F. and a night at either 80° F. or 74° F. A night temperature of 86° F. resulted in a rapid turn-over of small unhealthy leaves having a low chlorophyll content.

The gain in total plant dry weight was greatest at a night temperature of 74° F., smallest at a night temperature of 86° F., and the plants which maintained the greatest leaf areas also gained the most dry weight. Leaf dry weight per unit leaf area was greatest at the lowest temperatures, as was the ratio of total plant dry weight to leaf area. The ratio of leaf weight to plant weight showed a small but significant increase with increase in day temperature.     

红富士苹果树冠枝(梢)叶分布与温度、湿度的关系

以12a生红富士苹果(Malus.domestica Borkhcv.Red Fuji)为试材,研究了北京地区树冠不同层次和部位温度、相对湿度的分布、动态变化与枝叶数量间的关系。结果表明,树冠不同层次温度从上到下逐渐降低,同一层次内温度从内膛到外围逐步增大,树冠不同层次相对湿度从上到下逐渐增大,同一层次内相对湿度从内膛到外围逐步减小;树冠温度日变化呈白天低-高-低的趋势,相对湿度的日变化呈白天高-低-高的趋势,夜晚树体温度、相对湿度趋于一致;7—8月份冠层温度、相对湿度高于5—6月份和9—10月份。应用多元统计分析的方法建立了树冠温度、相对湿度与枝(梢)叶量关系的回归方程,冠层内不同层次、部位的温度、相对湿度受冠层内枝(梢)叶数量和分布的影响,冠层内温湿度与累计长、中、短枝(梢)量和叶面积系数成线性负相关,而相对湿度与之成线性正相关。综合分析,冠层有良好温度和相对湿度的群体结构参数为生长季每hm2总枝(梢)量100万左右,叶面积系数控制在3.5～4.0,长、中、短枝(梢)比例分别为73～77、10～12和13～15。     

西瓜苗期耐低温弱光性鉴定指标初探

研究了低温弱光（昼/夜温度 7.5 ℃,光照度 4 000 lx）下对 5 个西瓜品种苗期生长的影响,并对不同品种耐低温弱光性进行了比较。结果表明：根据低温弱光下西瓜幼苗生长量、冷害指数、叶片叶绿素含量变化,叶片电导百分率变化,不同品种表现差异明显。综合比较,朝霞耐低温弱光能力较强,金玉玲珑、5318 耐低温弱光能力次之,早春红玉、京欣 2 号耐低温弱光能力较弱。植物体内发生的生理反应与植物生长情况基本一致。幼苗生长量、冷害指数、叶片电导百分率、叶绿素含量可以作为西瓜苗期低温弱光抗性指标,几项指标应互相参照。     

Effects of N–P–K deficiency and temperature regime on the growth and development of Lilium longiflorum ‘Nellie White’ during bulb production under phytotron conditions

One-year-old scale bulblets of Lilium longiflorum Thunb. ‘Nellie White’ (Easter lily) were grown under a combination of six constant day/night temperature regimes and five N–P–K nutrient treatments under short days for 107 d (growing period 1 or GP-1) to compare the effects on growth and development and bulb production. Results during GP-1 were as follows: failure of bulblets to produce a shoot (“no-shows”) was found at high temperatures (30/26 and 26/22 °C) and not influenced by the nutrient treatments. Flower bud abortion was observed in the minus-N, minus-P, and minus-N–P–K treatments at high temperatures (30/26 or 26/22 °C), but not observed at any temperatures in the complete and minus-K treatments. The loss of bulb fresh weight in minus-N treated bulblets was less than in the other treatments resulting in less root and shoot growth in the minus-N treatment. At the intermediate temperatures where growth was highest, omission of N, P, K, or all three resulted in losses in stem bulb fresh weight, stem plus leaf fresh weight, number of flowers, and stem root fresh weight. Omission of N, P, or all three nutrients resulted in lowest basal root fresh weight. Bulb N and K concentrations were lowest in plants grown with complete nutrient solution at the two coldest temperature regimes (14/10 and 10/6 °C). Bulb P concentration was lowest at the three coldest (18/14, 14/10 and 10/6 °C) and the warmest (30/26 °C) temperature regimes. Stem length was shorter when P was omitted. Omission of any of the three nutrients resulted in lower concentrations of the other nutrients. The one exception was where low K did not affect N concentration. In the second phase of the experiment, plants grown at 18/14 °C and irrigated with the complete nutrient solution for 107 d (GP-1) were continued at this day/night temperature regime and five N–P–K nutrient treatments for another 89 d under long days (growing period 2 or GP-2). Results during GP-2 were as follows. Basal bulb yield was not impacted by omission of N, P, or K, or all three. Of all growth measurements, only stem plus leaf fresh weight was lower and only when all three nutrients (minus-N–P–K) were omitted. At the end of GP-2, basal bulb concentrations of N and P did not differ from the concentrations in bulbs at the beginning of GP-1; however, K concentration was lower at the end of GP-2. Omission of N or P further resulted in lower bulb K concentration, suggesting that a moderate supply of N, P, and K be applied during GP-2 since an additional year of bulb production is needed to produce forcing-sized bulbs.     

不同低温处理对甜瓜幼苗生长和根系生理特性的影响

以伊丽莎白和玉金香2个甜瓜品种为材料,研究了昼夜低温(10℃/5℃,昼/夜)和夜间低温(20℃/5℃,昼/夜)处理对甜瓜幼苗生长及根系生理指标的影响.试验结果表明,与对照温度(25℃/18℃)相比,昼夜低温和夜间低温处理7d均显著抑制了甜瓜幼苗生长,且昼夜低温处理比夜间低温处理有更高的根系MDA含量,对甜瓜幼苗伤害程度...     

Morphological responses of bedding plants to three greenhouse temperature regimes

Seedling crops of gazania, geranium, marigold, mimulus, pansy, verbena and vinca were grown to 60% anthesis in three greenhouse temperature regimes: (a) 26 °C day/6 ± 3 °C night (LT), with a 16.5 °C mean daily temperature (MDT), (b) 26 °C day/17 ± 4 °C night, with a 21 °C MDT, and (c) variable day/night temperatures in response to heating and cooling by a phase change material energy storage module (PCM) with an 8 ± 2 °C night and a 16 °C MDT. Crops bloomed from 2 to 17 days earlier in the 26 °C/17 °C greenhouse. The morphological characteristics of all cultivars of gazania, mimulus, pansy and verbena, geranium and vinca were similar regardless of greenhouse temperature regime. Marigold diploid and triploid cultivars and mimulus were morphologically more variable than the other bedding plant species. Crops grown in the PCM and LT greenhouses had virtually identical morphological characteristics and bloomed in about the same number of days. Plant height was not affected by DIF environments in the greenhouses. The PCM and LT greenhouses had a similar MDT, but the distribution of numbers of hours of mean daily temperatures was different.     

不同昼夜温度对水培生菜生长和品质的影响

利用人工气候箱研究了3种不同昼温（20℃/15℃,25℃/15℃和30℃/15℃）和夜温（30℃/25℃,30℃/20℃和30℃/15℃）对生菜生长和品质的影响。结果表明,随着昼温的升高,生菜的叶片数、地上部干鲜质量、根干鲜质量、叶面积等均显著增加。30℃条件下,茎长/茎粗的值显著增大,但并未造成抽薹现象,不影响生菜的商品性。综合昼温对水培生菜产量和品质的影响,昼温保持在25~30℃较为适宜。相对昼温,夜温对生菜生长影响较小。夜温从20℃降低到15℃,生菜地上部干鲜质量、根干鲜质量、叶片数和叶面积均无显著性变化,较低的夜温有助于抑制抽薹的发生,有利于提高生菜品质。     

露地黄瓜新品种津绿4号

在引进国内外品种资源的基础上,筛选出优良的自交系Ｆ１５和Ｑ２４,育成了丰产、抗病、品质优良的露地黄瓜新一代杂种津绿４号。其植株长势强,叶深绿色,以主蔓结瓜为主,第一雌花着生在第４节左右,雌花节率３５％左右。瓜条长棒形,长３５ｃｍ左右,单瓜重约２００ｇ。瓜把短,瓜皮深绿色,瘤显著,密生白刺,果肉绿白色、质脆,品质优,商品性好。早熟,从播种到采收约６０天,采收期６０～７０天。每６６７ｍ２产量５５００ｋｇ左右。耐热性强,对枯萎病、霜霉病、白粉病的抗性强,适于春秋露地栽培。