Light responses of photosynthesis and transpiration of two tomato cultivars under ambient and altered CO2 and O2

Young plants of two tomato (Lycopersicon esculentum L.) cultivars, ‘Sonatine’ and ‘F6-IVT’, were examined for whole plant photosynthesis and transpiration in a closed gas-exchange system under different light levels and a combination of high or low oxygen (21 or 1%) and high or low carbon dioxide concentrations (1850 or 550 mg m^?3). With saturating light, both cultivars showed approximately equivalent increases in photosynthesis in response to lowering the oxygen concentration, raising the carbon dioxide, or both. Under non-saturating light, ‘F6-IVT’ responded positively to lowered oxygen but CO₂ had little effect. In ‘Sonatine’, changes in O₂ as well as CO₂ gave photosynthetic enhancement under low light. Stomates responded primarily to CO₂ with little response to O₂. As a result of the stomatal behavior to light, plant water-use efficiency in the short term peaked at moderate light levels, was enhanced by low O₂, but was enhanced most by high CO₂, regardless of O₂ concentration.     

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 reducing the infrared radiation of sunlight on greenhouse temperature,leaf temperature,growth and yield

Infrared radiation, which is responsible for leaf temperatures that exceed the optimal for photosynthesis, was reduced by absorption in an aqueous CuSO₄ solution. A small greenhouse was constructed of double acryl plates through which a 0.5% CuSO₄ solution was circulated for infrared radiation filtration and cooling. The air temperature in this greenhouse never exceeded 30° C and the leaf temperature of the plants grown in this house was 10% lower than in a glass greenhouse. The yield of tomato plants grown in the acryl greenhouse, with infrared radiation filtration and receiving CO₂ enrichment during the entire light period, was not significantly increased as compared with the yield in the glass greenhouse with a similar CO₂ concentration. This may have been due to long periods with low light levels caused by extremely rainy and cloudy weather conditions, and by condensation on the inside surfaces of the acryl greenhouse caused by the high humidity.     

CO2 and air circulation effects on photosynthesis and transpiration of tomato seedlings

In the daytime, a CO₂ depletion of 10–15% and air circulation of less than 0.5 m s⁻¹ often occur in a naturally ventilated greenhouse during a sunny day with high wind speed (3–5 m s⁻¹). We, therefore, investigated the effects of moderate increase of the CO₂ concentration above the atmospheric level (500–600 μmol mol⁻¹) and air circulation up to 1.0 m s⁻¹ in a growth chamber on the net photosynthetic and transpiration rates of tomato seedlings as the first step. The average net photosynthetic rates were 2.1, 1.8, and 1.6 times higher in the growth chambers with increased CO₂ concentration (500–600 μmol mol⁻¹) and air circulation (1.0 m s⁻¹), increased CO₂ concentration, and increased air circulation, respectively, compared with those in the control (no increase in CO₂ concentration (200–300 μmol mol⁻¹) or air circulation (0.3 m s⁻¹). The transpiration rate increased with increased air circulation, while it decreased with increased CO₂ concentration regardless of air circulation. From the results, we consider that increasing the CO₂ concentration and/or air circulation in ventilated greenhouses up to the outside concentration (350–450 μmol mol⁻¹) and 1.0 m s⁻¹, respectively, can significantly increase the net photosynthetic rate of greenhouse plants.     

CO2 enrichment of greenhouse tomatoes using a closed-loop heat storage: Effects of cultivar and nitrogen

Spring crops of soil-grown greenhouse tomatoes (Lycopersion Lycopersicum (L.) Karst ex. Farw cultivars MO and TR-VE 23) were provided with three levels of nitrogen addition with and without added CO₂. Using a closed-loop solar collection/storage system, crops could be CO₂-enriched for 76–77% of the daylight hours. CO₂ enrichment increased No. 1 grade fruit weight by 14 and 27% and by 4 and 18% for both cultivars in 1981 and 1982, respectively. Although the method and amount of nitrogen application differed between 1981 and 1982, a trend was seen in both years for low nitrogen treatments to produce a greater response to CO₂ enrichment than high nitrogen treatments. A trend was also seen in both years for low nitrogen treatment to depress yield and quality in the non-enriched house, but to have no effect in the enriched house. This trend was particularly apparent in the cultivar with lower vegetative vigor, which also responded more overall to CO₂ enrichment than the cultivar with greater vegetative vigor.     

A simulation study on CO2 concentration in protected cultivation

In protected cultivation in The Netherlands, it is common practice that CO₂ enrichment is supplied by the heating system. The improvements in glasshouse insulation achieved during the last decade decreased both the air exchange of the glasshouse and the heat demand. During periods of low heat demand and high irradiance, the cumulative effect is a decrease of the CO₂ concentration considerably below ambient. Moreover, even with open ventilators, certain climatological conditions may cause a marked decrease of the CO₂ level in the glasshouse.This paper presents some physiological aspects of the problem. With emphasis on the CO₂-concentration level, estimates of the production of a typical glasshouse crop were made, as related to climate control in early spring.Economic aspects of additional CO₂ supply (independent of the heat demand) are presented.     

The influence of irradiance and external CO2-concentration on photosynthesis of different tomato genotypes

With 4 genotypes of tomato, irradiance and CO₂-response curves of net photosynthesis were analysed by means of curve fitting. Estimated values of the light compensation point I_c showed small but significant differences between the genotypes, the overall value being in the order of 8 W m^?2. The photochemical efficiency (α_n) and the maximum net photosynthesis per unit leaf area basis (P_nm) reached the highest values for ‘F6 IVT’ (13.3 μg CO₂ J^?1 resp. 0.549 mg CO₂ m^?2 s^?1), the lowest value of α_n with ‘Bonabel’ (9.9 μg CO₂ J^?1), and the lowest value of P_nm with ‘PI 114969’ (0.424 mg CO₂ m^?2 s^?1). The CO₂-compensation point (C_c) was relatively high (177–245 mg m^?3). ‘F6 IVT’ demonstrated the highest value of C_c, the lowest carboxylation efficiency and the highest maximum rate of net photosynthesis. The results clearly demonstrate that the latter genotype requires a much higher external CO₂-concentration than the other genotypes in order to exhibit the highest rate of net photosynthesis.     

CO2加富及亏缺灌溉对菜豆中期与后期生长的影响

为了探明菜豆中期与后期生长对CO₂加富与亏缺灌溉的生理响应,试验设两个CO₂水平:正常大气浓度和倍增CO₂浓度,两个灌溉水平:自然灌溉12次和亏缺灌溉6次,研究CO₂加富及亏缺灌溉对菜豆生长的影响。结果表明,CO₂加富显著提高菜豆生长中期株高与干质量,净光合速率(Pn)与胞间CO₂浓度(Ci)分别显著降低15.48%、37.67%,气孔导度(Gs)显著提高95.83%,菜豆生长后期的叶绿素a/b(Chla/b)显著提高12.29%,水分利用效率(WUE)显著提高46.51%,Ci显著降低12.87%。CO₂加富显著提高亏缺灌溉下生长中期菜豆的株高与干质量,但显著降低根冠比,显著提高叶绿素含量以及Gs;CO₂加富下生长后期的核酮糖-1,5-二磷酸羧化酶(Rubisco)及果糖-1,6-二磷酸酶(FBPase)活性分别显著提高78.05%与88.69%,CO₂加富使亏缺灌溉下碳酸酐酶(CA)与FBPase活性分别显著提高83.73%与64.84%。综上所述,CO₂加富提高菜豆生长中期对亏缺灌溉的适应性,对生长后期影响作用减小。     

光强阶跃下番茄叶片光合系统的响应动态

 在蓝光LED照射光强阶跃与反阶跃下,采用CIRAS-2光合测试系统和QE65000光纤光谱仪,同步测试分析了番茄叶片光合系统的CO₂吸收速率Pn、胞间CO₂浓度C_i、气孔导度G_s、叶绿素荧光F₆₈₀参数的动态响应。光强发生阶跃升高时,各阶跃阶点或起点下番茄叶片P_n动态进程均呈现从原稳态到终稳态趋饱和增加趋势,C_i均与P_n呈镜像对称的变化趋势,Gs均呈现轻微的先下降后回升的变化趋势,F₆₈₀均呈现轻微起伏式骤然升高趋势;而光强发生反阶跃下降时,各反阶跃落点或起点下番茄叶片P_n的动态进程均与光强阶跃升高时相反。在200 μmol &;#8226; m-2 &;#8226; s-1的相同阶跃量下,随着阶跃起点的增加,P_n从原稳态至终稳态的增幅逐渐减小。综合分析表明,在光强阶跃升高后,通过对叶绿素荧光F₆₈₀动态变化计算的非饱和激发光下的实际光化学效率Y(II)′ 随着光强阶跃量的增加呈现趋饱和增加趋势,这表明与光能电子传递速率有关的光强水平阶跃升高会给光合碳吸收提供更多的能量驱动力,从而表现出P_n从原稳态到终稳态的趋饱和增加;而在光强阶跃升高后G_s均维持在较高水平,虽在很短时间内有小幅下降波动,但是对CO₂进入胞间以及Pn的动态进程无显著影响;可是在光强阶跃升高后C_i下降幅度较大,与光合暗反应对胞间CO₂的快速吸收消耗有关,会对P_n的动态进程有一定程度影响。     

CO2 enrichment of strawberry and cucumber plants grown in unheated greenhouses in Israel

Strawberries and cucumber plants were grown in ambient atmospheric CO₂ concentrations of 300 v.p.m. and at elevated levels of 900, 1500 and 3000 v.p.m. during winter and early spring in 10 unheated greenhouses in the coastal plain of Israel. Co₂ enrichment averaged 7 hours per day between the end of November and the second half of April.Strawberry plants of cultivar ‘Tioga’ yielded 31, 43 and 51 % more than the control when subjected to a 3-, 5- and 10-fold increase in CO₂ concentration, respectively.Cucumber plants of cultivar ‘Elem’ grown at 3000 v.p.m. CO₂ yielded 26 % more over the whole picking season than those grown at 300 v.p.m. Yield during the first month of picking was doubled by both a 3- and a 10-fold increase in aerial CO₂ concentration.     

低氧低乙烯和高CO2处理对乔纳金苹果耐藏性的影响

以乔纳金苹果为试材,在不同气调贮藏条件下进行试验,当未脱除贮藏环境中的乙烯时,以在1 CO     

Effects of elevated CO2 on growth and morphological characteristics of ornamental bromeliads

Three ornamental bromeliads, i.e. Aechmea ‘Maya’ (CAM), Aechmea fasciata ‘Primera’ (CAM) and Guzmania ‘Hilda’ (C₃) were grown under greenhouse conditions at ambient (380 ppm) and elevated (750 ppm) CO₂. The effects of long-term exposure (34 weeks) to elevated CO₂ on growth and morphological traits constituting the ornamental value were assessed.     

Effects of shading and NO3:NH4 ratio on the yield,quality and N metabolism in strawberry

The effect of 50% shading and NO₃:NH₄ ratio (0:100, 75:25, 50:50, and 25:75) in the nutrient solution on growth, yield, quality and N metabolism in hydroponically grown strawberry (Fragaria × ananassa var Camarosa) was evaluated. Both fresh and dry weights of leaves were significantly lower when a high concentration of either NO₃ (100%) or NH₄ (75%) was the sole N source in the nutrient solution. In unshaded plants, increasing of both NH₄ and NO₃ ratio in the nutrient solution reduced photosynthetic (Pn) rate, however in shaded plants the reduction of Pn became more pronounced at a higher ratio of NH₄ in the nutrient solution. The yield in terms of fresh and dry weight of fruit per plant was significantly increased at the 75:25 and 50:50 (NO₃:NH₄) treatments. Fruit size was significantly affected by the treatments, so that the biggest fruits in both shaded and unshaded plants were obtained under the 75:25 and 50:50 (NO₃:NH₄) treatments. Total soluble solid (TSS) in unshaded plants was increased with increasing NH₄ ratio in the nutrient solution, however in shaded plants it was reduced at high NH₄ ratio in the nutrient solution. In both shaded and unshaded plants, higher concentration of NH₄ significantly reduced the post-harvest life of the fruits. The increase of tissue N concentration was nearly proportional to the NH₄ concentration in the nutrient solution. The activity of nitrate reductase (NR) was increased by increasing NH₄ from 0 to 50% and then reduced at a higher ratio of NH₄ in the solution. Shading increased NH₄ concentration so that the shaded plant had nearly twice as high NH₄ concentration in the leaves. The increase of NH₄ concentration induced by shading could be partially the reduction of NH₄ assimilate because of the shortage of carbohydrate.     

Storage of plug seedlings of tomato under limited fertilisation,and growth,flowering and yield after planting

We stored plug seedlings of tomato (Solanum lycopersicum L. cv. Momotaro) under limited fertilisation (LF) for 12 weeks, and evaluated growth and development during storage and after planting. Seedlings in the LF treatment were grown in substrate containing starter fertiliser and irrigated with water. Controls (CT) were irrigated with nutrient solution. Stem growth, leaf growth, and biomass accumulation slowed or ceased during storage of LF seedlings, while CT seedlings showed increases in these parameters. At 2 weeks after planting, the stem length of LF seedlings was shorter than that of CT seedlings, but the two seedling types had similar numbers of leaves. At harvest, LF and CT plants had similar numbers of leaves under the fruit trusses, but the trusses formed at lower heights in LF than in CT seedlings. LF and CT plants produced similar numbers of fruits and similar yields from the first to third trusses. These results indicate that tomato plug seedlings can be stored for more than 2 months under LF.     

Effects of CO2, temperature and their interaction on the growth, development and yield of cauliflower (Brassica oleracea L. botrytis)

Stands of summer cauliflower were grown within polyethylene-covered tunnels along which a temperature gradient was imposed. Two tunnels were maintained at either normal or elevated CO₂ concentrations. At the last harvest (88 days from transplanting) no interaction between CO₂ and temperature on total biomass was detected. The total dry weight of plants grown at 531 μmol mol⁻¹ CO₂ was 34% greater than those grown at 328 μmol mol⁻¹ CO₂, whereas a 1 °C rise reduced dry weight by 6%. From serial harvests the radiation conversion coefficient was 2.01 g MJ⁻¹ and 1.42 g MJ⁻¹ at 531 μmol mol⁻¹ CO₂and 328 μmol mol⁻¹ CO₂, respectively, but was not greatly affected by differences in temperature. No effect of either CO₂ or temperature on the canopy light extinction coefficient was detected. The rate of progress towards curd initiation increased to a maximum at 15.5 °C, and declined thereafter. Provided the effect of temperature was accounted for, CO₂ enrichment did not affect the time of curd initiation. From serial harvests after curd initiation, the logarithm of curd weight or diameter were negative linear functions of mean temperature from initiation. Increases in curd weight and diameter at 531 compared with 328 μmol mol⁻¹ CO₂ were greater at warmer temperatures (27% at 13 °C compared with 47% at 15 °C, 57 days after initiation). Effects of CO₂ on curd diameter were less than those on curd dry weight because the curd dry matter content was greater at 531 compared with 328 μmol mol⁻¹ CO₂. Thus, the effects of elevated CO₂ concentrations on fresh weight based yield parameters of cauliflower were less than the increase in total dry matter production.     

Effect of different light intensities on the photosynthate distribution in cherry tomato seedlings

To investigate the effect of varying the light intensity on the photosynthate distribution, cherry tomato (Solanum lycopersicum L.) seedlings were grown under different light intensities. It was found that the seedlings under 300 μmol m^–2 s^–1 had a significantly higher dry weight and health index (Health index = Stem diameter/Stem height × Dry weight) than seedlings receiving other light treatments. On the contrary, the biomass, specific leaf mass and health index values of seedlings exposed to 50 μmol m^–2 s^–1 and 550 μmol m^–2 s^–1 were the lowest among all of the treatments. In terms of ¹⁴C-labelled photosynthate translocation, the seedlings under 300 μmol m^–2 s^–1 had lower remaining ¹⁴C-labelled photosynthate (31.45%) compared with other treatments, after ¹⁴CO₂ was supplied for 2 days. The seedlings under 150 μmol m^–2 s^–1 had 36.97% of ¹⁴C-labelled photosynthate in the labelled leaves and transported the obviously higher ¹⁴C-labelled photosynthate to new shoot than others. Together, our results indicate that the photosynthate distribution was the most rational in cherry tomato seedlings at 300 μmol m^–2 s^–1, which enhanced leaf photosynthesis and plant growth.     

生态肥对温室有机番茄生长发育的影响

以有机番茄常规施肥种植为对照,将不同用量生态肥(50 kg/667 m2、75 kg/667 m2及100 kg/667 m2)作为基肥,研究生态肥不同用量对温室有机番茄生长发育及产量的影响。其中50 kg/667 m2生态肥处理,较对照增产41.50%,在栽培中均有促进番茄生长、提高作物抗病能力、增加番茄产量的效应。     

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.     

夜间亚低温处理及其恢复对番茄叶片光抑制的影响

 为探讨夜间亚低温对番茄叶片光合作用影响的生理机制,研究了9 ℃夜间亚低温处理及恢复条件下番茄叶片净光合速率(Pn)和叶绿素荧光参数的变化。结果表明:夜间9 ℃亚低温处理3 d以上,叶片Pn、PSII最大光化学量子产量(Fv/Fm)、PSII潜在的活性(Fv/Fo)、实际光化学量子效率(фPSII)、PSII的电子传递速率（ETR）、光化学猝灭系数（qP）均下降,初时荧光(Fo)、PSII的还原状态(1-qP)、非光化学猝灭系数(NpQ)均提高;但夜间9 ℃亚低温处理9 d以内,除了NpQ在9 d恢复性处理后仍未恢复到对照水平外,其它叶绿素荧光参数均恢复到对照水平。上述结果说明：9 ℃夜间亚低温处理3 d就明显引起番茄成熟叶片光合作用的光抑制,而9 d以下的夜间9 ℃亚低温处理对PSII的影响是可逆的,即短期9 ℃夜间亚低温所引起的番茄叶片光合作用的光抑制现象是可以恢复的。     

Effect of elevated CO2 on vegetative and reproductive growth characteristics of the CAM plants Hylocereus undatus and Selenicereus megalanthus

This study examined the vegetative and reproductive growth responses of the crassulacean acid metabolism (CAM) vine-cactus fruit crop species Hylocereus undatus and Selenicereus megalanthus to CO₂ enrichment (1000 μmol mol⁻¹ vs. control of 380 μmol mol⁻¹). H. undatus plants enriched with CO₂ demonstrated 52%, 22%, 18%, and 175% increases, relative to plants measured in ambient CO₂, in total daily net CO₂ uptake, shoot elongation, shoot dry mass, and number of reproductive buds, respectively. The responses of S. megalanthus plants exposed to elevated CO₂ were greater than those of H. undatus under the same conditions. Compared to plant responses in ambient CO₂, under conditions of CO₂ enrichment, S. megalanthus showed 129%, 73%, 68%, and 233% increases in total daily net CO₂ uptake, shoot elongation, shoot dry mass, and number of reproductive buds, respectively. Moreover, for H. undatus, there was no significant change in fruit fresh mass although it showed a slight (7%) upward trend. On the other hand, fruit fresh mass of S. megalanthus significantly increased by 63% in response to elevated CO₂. These results indicate the high potential of CAM plants to respond to CO₂ enrichment. It is thus apparent that S. megalanthus grown under CO₂ enrichment may benefit from elevated CO₂ to a greater extent than H. undatus grown under sub-optimal growth conditions.