Light quality and temperature effects on antirrhinum growth and development

Light quality and temperature effects on antirrhinum growth and development 1 first-author †E-mail:amkhatta@brain.net.pk; Simon.Pearson@marks-and-spencer.com †E-mail:amkhatta@brain.net.pk; Simon.Pearson@marks-and-spencer.com amkhatta@brain.net.pk 2 †E-mail:amkhatta@brain.net.pk; Simon.Pearson@marks-and-spencer.com †E-mail:amkhatta@brain.net.pk; Simon.Pearson@marks-and-spencer.com amkhatta@brain.net.pk Department of Horticulture, NWFP Agricultural University, Peshawar, Pakistan Department of Horticulture, NWFP Agricultural University, Peshawar, Pakistan Marks and Spenser Public Limited Company, Michael House, Baker Street, London WIA 1DN, UK Marks and Spenser Public Limited Company, Michael House, Baker Street, London WIA 1DN, UK An experiment was carried out to examine the effects of light quality on the growth and development of antirrhinum under three different temperatures 19 °C, 24 °C and 27 °C in glasshouses. Five different colour filters (i.e. ‘Red absorbing’, ‘Blue absorbing’, ‘Blue and Red absorbing’ and two ‘partially Blue absorbing’ materials) were tested, with one clear polythene as a control. Plant height, internode length and leaf area were significantly affected by the spectral filters as well as the temperature. Analysis of color filter’s effect on presumed photoreceptors to exist indicated that antirrhinum plant height was regulated by the action of a blue acting photoreceptor (BAP) and not the phytochrome. There was no evidence for an effect of phytochrome or BAP on time to flowering, however, increasing temperature levels effectively decreased the time to flowering. To predict the effects of different spectral qualities and temperature, simple models were created from data on plant height, internode length and time to flowering. These models were then applied to simulate the potential benefits of spectral filters and temperature in manipulation of growth control and flowering in antirrhinum. Antirrhinum Light quality Temperature Spectral filters Photoreceptors INTRODUCTION 1 Much interest has been shown in non-chemical means of plants growth control during the past decade. Manipulation of temperature, light quality and quantity, have been proposed as methods of plant height control (Mortensen and Stromme, 1987 1987 ; Heins and Erwin, 1990 1990 ; McMahon and Kelly, 1990 1990 ). Considerable previous research focused on the manipulation of day/night temperatures for growth control (Erwin et al., 1989 1989 ; Moe et al., 1995 1995 ). In many plants, height was reduced when they were grown with higher night than day temperature, but leaf chlorosis, and delayed flowering has limited the use of temperature manipulation for plant growth regulation (Karlsson et al., 1989 1989 ). A number of studies have examined whether the manipulation of spectral quality has potential for growth control in a range of ornamental plants (Mortensen and Stromme, 1987 1987 ; Mortensen, 1990 1990 ; McMahon et al., 1991 1991 ; Rajapakse and Kelly, 1992 1992 ; Rajapakse et al., 1993 1993 ; Rajapakse and Kelly, 1995 1995 ; Van Haeringen et al., 1998 1998 ). Light quality has been demonstrated to influence many aspects of plant growth and morphology (Smith, 1982 1982 ; 1995 1995 ). It has been suggested that rigid or flexible plastic greenhouse covers with specific spectral qualities, would enable growers to use light quality to regulate the growth of greenhouse crops (Rajapkse and Kelly, 1993 1993 ). Khattak and Pearson ( 1997 1997 ) showed that spectral filters had remarkable effects on chrysanthemum growth and flowering. However, it was observed that most previous work on spectral filters was conducted on chrysanthemum, which is a short day plant (McMahon et al., 1991 1991 ; Rajapakse and Kelly, 1991 1991 ; 1992 1992 ; Rajapakse et al., 1992 1992 ; 1993 1993 ; Rajapakse and Kelly, 1995 1995 ). Mortensen and Stromme ( 1987 1987 ) studied light quality effects on vegetables (tomato and lettuce), but little work seems to have been done on antirrhinum under natural light conditions. Responses of long day plants such as antirrhinum have also been rarely studied under different temperature regimes. Here the responses of antirrhinum, a long day plant, to spectral filters were studied under condition similar to those of chrysanthemums (Khattak and Pearson, 1997 1997 ) so that their growth and development could be compared. MATERIALS AND METHODS 1 Plant material and treatments 2 The experiment was conducted in the School of Plant Sciences, University of Reading, UK. Antirrhinum majis (Cv. Coronatte yellow) seeds were purchased from Colgrave Seeds and sown in module trays having SHL (Sinclair Horticulture Ltd., Lincoln, UK) seed and modular compost on July 18, 1996. The seeds were covered with a thin layer of vermiculite, watered and put in a growth room set at 15 °C and lit at 100 μmol/(m 2 ·s) with white fluorescent tubes for 16 h/d. The trays were kept moist until germination. The seeds germinated on July 26, 1996 and the seedlings were watered at two or three days intervals (as needed). Twenty days later, the seedling trays were moved from the nursery room to an oriented southward glasshouse (5 m×8 m×4 m high) set at 15 °C. The next day, the seedlings were put in 9 cm pots containing a mixture of 75% potting compost and 25% perlite. Three days later, the plants were transferred to one of three identical (adjacent, similar in size and shape, with same light intensity) glasshouse compartments set at three different temperatures i.e. 15 °C, 20 °C and 25 °C (thermostatically controlled heating and cooling). However, the actual temperatures recorded were 19 °C, 24 °C and 27 °C respectively. In each compartment there were six different spectral filters replicated twice (Khattak and Pearson, 1997 1997 ). The filters were wrapped on wooden frames making chambers of 30 cm width, 60 cm length and 60 cm height. Four plants were placed in each filter-covered chamber. At flowering, the plants were harvested and measured for final plant height, stem fresh and dry weight, leaf area, leaf fresh and dry weight, number of flowers, flower fresh and dry weights, etc. Spectral filters 2 Six different solid spectral filters were used, 5 obtained from Lee Filters Ltd., Andover, UK (filters 088, 101, 109, 110, 117), and 150 μm clear low density polyethylene (LDPE) was used as a control. The filters were selected so that the analysis could test for independent effects of a Blue Acting Photoreceptor (BAP) using the light equivalence principle described by Schafer et al.( 1981 1981 ), such that they would provide the same overall Photosynthetically Active Radiation (PAR) transmission and phytochrome photoequilibrium ( φ ; phi), but have different ‘blue’ transmissions. Other claddings were chosen that gave different phytochrome photoequilibria. The actual spectral transmissions of 300 to 800 nm for each of the materials were measured on an optical bench using a Bentham Instruments spectroradiometer (M3000EA monochromator), as described by Pearson et al.( 1995 1995 ), and are shown in Fig. 1 1 . The R (red):FR (far-red), B (blue):R and B:FR ratios were then calculated assuming a narrow band absorption (1 nm) for each wavelength. Phytochrome photoequilibria ( φ ) constants were estimated using the model of Hayward ( 1984 1984 ). Table 1 1 gives a summary of the transmissions recorded for all the spectral materials. Photosynthetically Active Radiation (400–700 nm) Calculated using a Li-Cor quantum sensor Calculated as the transmission of quanta assuming a standard solar spectral distribution (Pearson et al., 1995 1995 ) Calculated as the proportion of blue quanta transmitted relative to the total PAR quanta incident above the cladding n/a: not available 2 Filters 2 PAR 1 1 Transmission (%) 2 R:FR (660:730) 2 B:R (450:660) 2 B:FR (450:730) 2 Phi ( φ ) 2 Blue 4 4 (400–500 nm) (%) 2 Absorption A 2 2 B 3 3 Control 63.9 n/a 5 5 1.38 0.78 1.08 0.73 30.1 Neutral 88 52.4 54.4 0.57 0.00 0.00 0.66 13.8 Blue and red absorbing 101 63.1 64.9 1.14 0.00 0.00 0.73 3.3 Blue absorbing 109 59.9 63.3 1.15 0.36 0.41 0.72 19.8 Partially Blue absorbing 110 63.1 65.4 1.17 0.51 0.60 0.72 25.9 Partially blue absorbing 117 57.4 58.2 0.43 2.02 0.88 0.60 42.1 Red absorbing Data collection and analysis 2 Temperatures inside each glasshouse compartment were recorded using a Campbell CR 7 data logger via aspirated K type thermocouples. In order to measure air temperature and protect them from direct sunlight, the sensors were fixed in the middle of pipes (40 cm long×8 cm diameter) with small fans fixed to one end which would blow air into the pipe from outside. The average temperatures recorded over the duration of the experiment were 19 °C, 24 °C and 27 °C. The daily PAR light integral received outside the greenhouse (measured with a Kipp solarimeter) averaged over the duration of the experiment was 12.15 MJ/(m 2 ·d), which was further reduced 20% by the greenhouse cladding. Different plant growth and development parameters were measured including plant height, internode length, leaf number, area and weight, stem weight and flowering. All the data taken were subjected to analysis of variance (2 factor) or multiple linear regression analysis. MSTATC software (Michigan State University, USA) was used for computing analysis of variance and least significant difference (LSD) tests, and MS Excel for regression analysis. RESULTS 1 Effects of spectral filters and temperature 2 A detailed comparison of the effects of spectral filters and temperature on the growth and development of antirrhinum is given in Table 2 2 . PH : Plant height; IL : Internode length; NL : Number of leaves; LA : Leaf area; LFW : Leaf fresh weight; LDW : Leaf dry weight; SLW : Specific leaf weight; SFW : Stem fresh weight; SDW : Stem dry weight; DF : Days to flowering; F : Filter; T : temperature; NS: Non significant Significant at P ≤0.05 Significant at P ≤0.01 Significant at P ≤0.001 PH (cm) IL (cm) NL LA (cm 2 ) LFW (g) LDW (g) SLW (mg/cm 2 ) SFW (g) SDW (g) DF (d) Filters Control 38.9 1.82 21.4 568.9 16.35 1.58 2.76 7.39 1.02 65.7 88 45.3 2.01 22.7 500.3 12.82 1.26 2.45 7.35 1.01 68.6 101 50.0 2.26 22.2 553.7 14.29 1.44 2.59 9.05 1.22 66.4 109 42.4 1.93 22.0 509.3 14.46 1.38 2.68 7.08 1.07 67.3 110 39.9 1.83 21.8 485.7 13.85 1.39 2.79 6.96 0.94 66.2 117 38.7 1.84 21.0 396.6 11.22 1.07 2.69 5.17 0.71 66.7 Significance *** *** *** *** *** *** * * ** ** * * NS *** *** *** *** NS LSD values 3.95 0.21 0.88 89.33 3.14 0.30 1.82 0.24 Temperature 19 °C 47.6 2.23 21.3 679.8 20.33 1.95 2.90 12.62 1.66 72.5 24 °C 42.3 1.92 22.1 462.7 12.04 1.23 2.67 5.74 0.86 66.5 27 °C 37.6 1.70 22.1 364.7 9.12 0.88 2.41 3.13 0.46 61.5 Significance *** *** *** *** ** ** *** *** *** *** *** *** ** ** *** *** *** *** *** *** LSD values 2.8 0.15 0.6 86.8 2.22 0.29 0.42 1.29 0.17 1.9 Interaction F × T NS NS NS NS NS NS NS * * NS NS Significant differences ( P ≤0.001) were found in plant height measured at flowering. There was a strong effect of blue light on antirrhinum plant height (PH in Table 2 2 ). Plant height decreased with the increase in blue light. However, there was no indication of an effect of φ on plant height. The 117, control and 110 materials had the lowest plant heights of 38.7, 38.9 and 39.9 cm, respectively. These materials had relatively high blue transmission (24.0%, 21.9% and 18.3% respectively) but different φ . The tallest (50.0 cm) plants were produced by the 101 material, which had high φ , but the lowest blue (3.3%) transmission. Thus, the data suggested that there was evidence for the action of a blue photoreceptor, since materials with relatively higher blue transmission had significantly ( P ≤0.001) shorter plants than those with low blue transmission independent of φ . Variations in temperature also resulted in significantly different heights. The tallest (47.6 cm) plants were produced at the lowest temperature (19 °C), followed by 24 °C (42.3 cm) and the lowest height (37.6 cm) was recorded for the plants grown under the highest temperature (27 °C). This was because plants grown under the highest temperature flowered about a week earlier than those of other temperatures. Spectral filters significantly ( P ≤0.001) affected internode length (IL in Table 2 2 ). The material with the lowest blue transmission (101) had the longest (2.26 cm) internodes compared to the rest of the materials. The other materials behaved similarly, although there were slight differences, depending on the amount of blue light present. The effect of temperature on internode length was almost identical to that on plant height. The lowest temperature (19 °C) produced the longest (2.23 cm) internodes whose length decreased ( P ≤0.001) with the increase in temperature i.e. 1.92 cm at 24 °C and 1.70 cm at 27 °C. However, the plants under the higher temperatures flowered earlier than the plant under lower temperature. The leaf number (NL in Table 2 2 ) was also affected significantly ( P ≤0.01) by the spectral filters. But the differences in leaf number were small, with the difference between the highest and lowest NL being 1.7 leaves. The lowest leaf number was produced by the 117 and Control materials, which had different φ but relatively high blue transmission. This shows that φ had little effect on leaf number, while blue light or a blue photoreceptor (BAP) may reduce the number of leaves in antirrhinum. The effect of temperature was obvious and the leaf number was affected significantly ( P ≤0.01), where the lowest (19 °C) temperature led to the lowest number of leaves. In terms of leaf area (LA in Table 2 2 ), there was no evidence for an effect of a blue photoreceptor, since the control, 110, 109 and 101 filters (same φ but different levels of blue) had similar leaf areas. There was a suggestion that low φ led to a reduced leaf area, since the 117 filter (low φ , but high blue transmission) led to the lowest ( P ≤0.05) leaf area (30.3% lower than the control). The plants grown at the highest (27 °C) temperature had the smallest ( P ≤0.001) leaf area, which increased as temperature decreased, with the lowest (19 °C) temperature leading to the largest leaf area (679.8 cm 2 ). Spectral filters significantly affected the leaf fresh ( P ≤0.01) and dry ( P ≤0.05) weights. The control material (high φ ) produced the highest leaf fresh and dry weights (LFW and LDW in Table 2 2 ), whereas 117 (low φ , high blue) and 088 (low φ , low blue) produced the lowest weights (the 088 material weighed 21% and 117 weighed 31% lower than the control). These results show that blue light had no effect, but that φ apparently had effect, since the materials with the same high φ but different blue (i.e. control, 101, 109, 110) had similar but higher leaf fresh and dry weights compared to those with low φ . Like leaf area, temperature variation greatly affected LFW and LDW. The highest weights ( P ≤0.001) were recorded for the lowest temperature (19 °C) and the weights decreased as temperature increased, with the highest temperature (27 °C) producing the lowest leaf weights. Specific leaf weight is the leaf dry weight per unit leaf area, and represents the thickness of the leaf. The data recorded (SLW in Table 2 2 ) showed that the spectral materials had no significant effect on specific leaf weight. Different temperatures, on the other hand, significantly ( P ≤0.01) affected the specific leaf weight. The lowest temperature (19 °C) led to the highest (2.90 mg/cm 2 ) SLW but the highest temperature (27 °C) led to the lowest (2.41 mg/cm 2 ) SLW. Thus, low temperature produced thicker leaves while high temperature led to thinner leaves. Both the stem fresh and dry weights (SFW and SDW in Table 2 2 ) were significantly ( P ≤0.001) affected by the spectral filters. It seems that stem dry weight was affected by a BAP, since the weight was inversely related to the proportion of blue light transmitted by the materials. The materials with the lowest blue transmission (101) had the highest (1.22 g) stem dry weight, while the material with highest blue transmission (117) had the lowest (0.71 g) stem dry weight. However, in case of stem fresh weight, significant ( P ≤0.05) interaction was observed between temperature and spectral filters. At the lowest temperature (19 °C), filter 101 produced the highest SFW, followed by 088, while the control and 110 produced similar SFW. The 117 filter behaved consistently at all temperatures producing the lowest LFW. At 24 °C, the filters 101, 109 and control produced higher SFW than the rest, whereas, at 27 °C, filter 109 produced the highest SFW. Temperature regimes significantly ( P ≤0.001) affected stem dry weight. Plants grown at 19 °C had the highest dry weights (1.66 g), and the weight decreased as the temperature increased. The variation in spectral quality had no significant effect on time to flowering in antirrhinum. However, the data (DF in Table 2 2 ) show that minimum DF (65.7) were found in the control (high φ and high blue), and maximum (68.6) DF were noted under the 088 filter (low φ and low blue). Temperature showed strong effects on time to flowering. Plants grown at the highest temperature (27 °C) were the earliest to flower. Flowering delayed by 5 and 11 d as the temperature was decreased to 24 °C and 19 °C, respectively. Simulation of the effects of spectral filters and temperature 2 The data were also analysed using multiple regression analysis to develop simple quantitative relationships, which could be used to model plant height, internode length and time to flowering for plants grown under any spectral filter. Antirrhinum plant height (PH) was found to be a function of the amount of blue light (B) in the incident radiation (MJ/(m 2 ·d); 400–500 nm) and temperature ( T , °C), so that PH =63.05±3.66−12.72±1.70 B −0.67±0.15 T ( r 2 =0.83, 15 d.f.) Like the Analysis of variance (ANOVA), φ had no significant effect on PH . For internode length as well, the amount of blue light and temperature both had significant effects, but φ had no effect; IL =3.03±0.17−0.45±0.08 B −0.04±0.007 T ( r 2 =0.81, 15 d.f.) Time to flowering (DF) in antirrhinum was found to be a function of the prevailing temperature only, and was not affected by amount of blue light present or the phytochrome photoequilibrium, so that DF =98.41±2.74−1.35±0.12 T ( r 2 =0.89, 16 d.f.) DISCUSSION 1 The data presented here show clearly that spectral quality has substantial effect on the growth and development of antirrhinum. There was a strong effect of blue light on plant height confirming the presence of a photoreceptor acting in the blue region of the spectrum. Significant reductions were found in the plant height with the increase in blue transmission confirming previous studies on other species (Mortensen and Stromme, 1987 1987 ; Thomas and Dickinson, 1979 1979 ; Young, 1981 1981 ; Mortensen, 1990 1990 ). However, it was surprising that phytochrome photoequilibrium ( φ ) did not appear to have any effect on the plant height. These results are in contrast to results reported in Khattak and Pearson ( 1997 1997 ) where the chrysanthemum plant height was strongly affected by φ as well as blue light. This might be due to species sensitivity because, according to Casal ( 1994 1994 ), some plants are more sensitive to blue, some to φ , while for some there is an interaction between blue and φ . The 088 and 117 materials (having low φ ) produced the smallest leaf areas and leaf fresh and dry weights. The same effects were found for chrysanthemum (Khattak and Pearson, 1997 1997 ). This confirms that the effect was due to phytochrome. Variation in temperature greatly affects plant growth and flowering. The plant height and internode length increased as the temperature increased above 19 °C. These results are in consistence with results of Mortensen and Larsen ( 1989 1989 ), who observed a decrease in shoot length at high temperature (above 22 °C) for some plants. The interactions between light quality and temperature were largely not significant, suggesting that the spectral filters operate effectively over a wide range of temperatures. The data on time to flowering showed that light quality had no effect on flowering time. This might be that antirrhinum is a long day plant (LDP) and the experiment was carried out during long days when the plants flowered rapidly before the light quality had effect. Furthermore, in LDP far red is known to be required for flowering and in antirrhinum Van Haeringen et al.( 1998 1998 ) showed that removal of FR delayed flowering. This is quite different from a red far-red (R-FR) response and more like high irradiance (HI) response where intensity of FR is important (Carr-Smith et al., 1989 1989 ). In such instances φ will not therefore indicate the level of response. Here all the filters changed the φ , but did not affect FR transmission. This and the Van Haeringen’s study therefore suggests an independent effect of FR on flowering of antirrhinum, which is not modulated by a classical R-FR reversal mechanism. References HD Carr-Smith , CB Johnson , B Thomas . Action spectrum for the effect of day-extensions on flowering and apex elongation in green, light-grown wheat (Triticum aestivum L.) . Planta , 1989 . 179 428 - 432 . . Action spectrum for the effect of day-extensions on flowering and apex elongation in green, light-grown wheat (Triticum aestivum L.) JJ Casal . Stem extension growth responses to blue light require Pfr in tomato seedlings but are not reduced by low phytochrome levels of the aurea mutant . Physiologia Plantarum , 1994 . 91 263 - 267 . . Stem extension growth responses to blue light require Pfr in tomato seedlings but are not reduced by low phytochrome levels of the aurea mutant JE Erwin , RD Heins , MG Karlsson . Thermomorphogenesis in Lilium longiflorum . Amer. J. Bot. , 1989 . 76 47 - 52 . . Thermomorphogenesis in Lilium longiflorum PM Hayward . H Smith , MG Holmes . Determination of phytochrome parameters from radiation measurements . Techniques in Photomorphogenesis , 1984 . : London Academic Press , 159 - 173 . . Determination of phytochrome parameters from radiation measurements RD Heins , JE Erwin . Understanding and applying DIF . Greenhouse Grower , 1990 . 8 ( 20 ): 73 - 78 . . Understanding and applying DIF MG Karlsson , RD Heins , JE Erwin , RD Berghage , WH Carlson , JA Biernbaum . Temperature and photosynthetic photon flux influence chrysanthemum shoot development and flower initiation under short-day conditions . J. Amer. Soc. Hort. Sci. , 1989 . 114 ( 1 ): 158 - 163 . . Temperature and photosynthetic photon flux influence chrysanthemum shoot development and flower initiation under short-day conditions AM Khattak , S Pearson . The effects of light quality and temperature on the growth and development of chrysanthemums cvs Bright Golden Ann and Snowdon . Acta Horti. , 1997 . 435 113 - 122 . . The effects of light quality and temperature on the growth and development of chrysanthemums cvs Bright Golden Ann and Snowdon MJ McMahon , JW Kelly . Influence of spectral filters on height, leaf chlorophyll, and flowering of Rose x hybrida ‘Meirutral’ . J. Environ. Hort. , 1990 . 8 209 - 211 . . Influence of spectral filters on height, leaf chlorophyll, and flowering of Rose x hybrida ‘Meirutral’ MJ McMahon , JW Kelly , DR Decoteau , RE Young , RK Pollock . Growth of Dendranthema × Grandiflorum (Ramat.) kitamura under various spectral filters . J. Amer. Soc. Hort. Sci. , 1991 . 116 ( 6 ): 950 - 954 . . Growth of Dendranthema×Grandiflorum (Ramat.) kitamura under various spectral filters R Moe , K Willumsen , IH Ihlebekk , AI Stupa , NM Glomsrud , LM Mortensen . DIF and temperature drop responses in SDP and LDP, a comparison . Acta Horti. , 1995 . 378 27 - 32 . . DIF and temperature drop responses in SDP and LDP, a comparison LM Mortensen . Effects of temperature and light quality on growth and flowering of Begonia hiemalis Fotsch. and Campanula iaophylla Moratti . Scientia Horti. , 1990 . 44 309 - 314 . . Effects of temperature and light quality on growth and flowering of Begonia hiemalis Fotsch. and Campanula iaophylla Moratti LM Mortensen , E Stromme . Effects of light quality on some greenhouse crops . Scientia Horti. , 1987 . 33 27 - 36 . . Effects of light quality on some greenhouse crops LM Mortensen , G Larsen . Effects of temperature and light quality on growth of six foliage plants . Scientia Horti. , 1989 . 39 149 - 159 . . Effects of temperature and light quality on growth of six foliage plants S Pearson , AE Wheldon , P Hadley . Radiation transmission and fluorescence of nine greenhouse cladding materials . J. Agri. Eng. Res. , 1995 . 62 61 - 70 . . Radiation transmission and fluorescence of nine greenhouse cladding materials NC Rajapakse , JW Kelly . Influence of CuSO 4 filters and exogenous gibberellic acid on growth of Dendranthema grandiflorum (Ramat.) Kitamura ‘Bright Golden Ann’ . J. Plant Growth Regulat. , 1991 . 10 207 - 214 . . Influence of CuSO4 filters and exogenous gibberellic acid on growth of Dendranthema grandiflorum (Ramat.) Kitamura ‘Bright Golden Ann’ NC Rajapakse , JW Kelly . Regulation of chrysanthemum growth by spectral filters . J. Amer. Soc. Hort. Sci. , 1992 . 117 ( 3 ): 481 - 485 . . Regulation of chrysanthemum growth by spectral filters NC Rajapakse , JW Kelly . Spectral filters influence transpiration water loss in chrysanthemum . HortSci. , 1993 . 28 ( 10 ): 999 - 1001 . . Spectral filters influence transpiration water loss in chrysanthemum NC Rajapakse , JW Kelly . Spectral filters and growing season influence growth and carbohydrate status of chrysanthemum . J. Amer. Soc. Hort. Sci. , 1995 . 120 ( 1 ): 78 - 83 . . Spectral filters and growing season influence growth and carbohydrate status of chrysanthemum NC Rajapakse , RK Pollock , MJ McMahon , JW Kelly , RE Young . Interpretation of light quality measurements and plant response in spectral filter research . HortSci. , 1992 . 27 ( 11 ): 1208 - 1211 . . Interpretation of light quality measurements and plant response in spectral filter research NC Rajapakse , MJ McMahon , JW Kelly . End of day far-red light reverses height reduction of chrysanthemum induced by CuSO 4 spectral filters . Scientia Horti. , 1993 . 53 249 - 259 . . End of day far-red light reverses height reduction of chrysanthemum induced by CuSO4 spectral filters E Schafer , CJ Beggs , L Fukchansky , MG Holmes , M Jabben . A method to check the involvement of additional photoreceptor to phytochrome in photomorphogenesis . Eur. Symp. Light Med. Plant Dev. , 1981 . 9 14 (Bischofmais, Germany) . A method to check the involvement of additional photoreceptor to phytochrome in photomorphogenesis H Smith . Light quality, photoperception, and plant strategy . Ann. Rev. Plant Physiol. , 1982 . 33 481 - 518 . . Light quality, photoperception, and plant strategy H Smith . Physiological and ecological function with in the phytochrome family . Annu. Rev. Plant Physiol. Plant Mol. Biol. , 1995 . 46 289 - 315 . . Physiological and ecological function with in the phytochrome family B Thomas , HG Dickinson . Evidence for two photoreceptors controlling growth in de-etiolated seedling . Planta , 1979 . 146 545 - 550 . . Evidence for two photoreceptors controlling growth in de-etiolated seedling CJ Van Haeringen , JS West , FJ Davis , A Gilbert , P Hadley , S Pearson , AE Wheldon , RGC Henbest . The development of solid spectral filters for the regulation of plant growth . Photochem. and Photobiol. , 1998 . 67 407 - 413 . . The development of solid spectral filters for the regulation of plant growth JE Young . Light quality and stem growth in Impatiens parviflora . New Phytol. , 1981 . 89 47 - 59 . . Light quality and stem growth in Impatiens parviflora 10.1631/jzus.2005.B0119 2004-08-09 2004-09-20 2005-01-20 2022-01-05 Copyright © 2005, Journal of Zhejiang University Science 2005 Journal of Zhejiang University-SCIENCE B (Biomedicine and Biotechnology) 02 6B