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

P. Thongbai  T. Kozai  K. Ohyama 《Scientia Horticulturae》2010

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.  相似文献   

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

Israel Weiss  Yosef Mizrahi  Eran Raveh 《Scientia Horticulturae》2010

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.  相似文献   

Analysis and modeling of gas exchange processes in Scaevola aemula     

Soo-Hyung Kim  Paul R. Fisher  J. Heinrich Lieth 《Scientia Horticulturae》2007

Scaevola aemula is a popular ornamental crop cultivated as a bedding plant or for hanging baskets. We characterized gas exchange properties of S. aemula ‘New Wonder’ in response to photosynthetically active radiation (PAR), carbon dioxide concentration, and leaf temperature. Net CO₂ assimilation rate (A) was responsive to CO₂, exhibiting a saturation when intercellular CO₂ concentration (C_i) was greater than 600 μmol mol⁻¹. Net CO₂ assimilation rate and dark respiration rate (R_d) were 23.1 and 2.3 μmol m⁻² s⁻¹, respectively, at 25 °C and PAR = 1500 μmol m⁻² s⁻¹. Net CO₂ assimilation rates were similar at leaf temperatures between 20 and 30 °C but significantly reduced at 15 °C. These gas exchange results were used to test the extendibility of a coupled gas exchange model previously developed for cut-roses. Utilizing the gas exchange data measured at 25 °C leaf temperature, several model parameters were independently determined for S. aemula. Model predictions were then compared with observations at different leaf temperatures. The model predicted the rates of net CO₂ assimilation and transpiration of S. aemula reasonably well. Without additional calibration, the model was capable of predicting the temperature dependence of net CO₂ assimilation and transpiration rates. Applying the model to predict the effects of supplemental lighting and CO₂ enrichment on canopy photosynthesis and transpiration rates, we show that this model could be a useful tool for examining environmental control options for S. aemula production in the greenhouse.  相似文献   

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

S. Croonenborghs  J. CeustersE. Londers  M.P. De Proft 《Scientia Horticulturae》2009

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.  相似文献   

Higher than optimum temperature under CO₂ enrichment influences stomata anatomical characters in rose (Rosa hybrida)     

Renu Pandey  Priya M. Chacko  M.L. Choudhary  K.V. Prasad  Madan Pal 《Scientia Horticulturae》2007

There is little available information on the effects of temperature and CO₂ enrichment on stomata anatomical characteristics of plants. Effect of these two microclimates was studied on five rose (Rosa spp.) cultivars, viz. ‘First Red’ (used as check), ‘Arjun’, ‘Raktima’, ‘Raktagandha’ and ‘Pusa Pitamber’. Budded, single-stemmed rose cultivars having five lateral buds were grown in controlled environment growth cabinets under enriched CO₂ (1000 μmol mol⁻¹) and optimum (28/18 °C, T₀) or high (35/25 °C, T₁) temperature for 50 days. All observations were made on the abaxial leaf surface. Significant increases in stomatal density (68.7%), index (29.6%) and epidermal cell density (37.3%) were recorded in plants grown at high temperature over control with CO₂ enrichment. The cultivars responded differently in terms of length and width of guard cell and stoma (pore) under high temperature, however, the values averaged over treatments showed a significant reduction in these parameters. Further, number of stomata per leaf was higher (28.3%) in plants grown at high temperature, except First Red. A reduction in mean leaf area (26.7%) and dry mass (32.0%) was recorded at high rather than optimum temperature. The specific leaf area was maximum in Arjun (87%) while in First Red, a 14% reduction was noted at high temperature.  相似文献   

Does root-sourced ABA play a role for regulation of stomata under drought in quinoa (Chenopodium quinoa Willd.)     

Sven-Erik Jacobsen  Fulai LiuChristian Richardt Jensen 《Scientia Horticulturae》2009

The Andean seed crop quinoa (Chenopodium quinoa Willd.) is traditionally grown under drought and other adverse conditions that constrain crop production in the Andes, and it is regarded as having considerable tolerance to soil drying. The objective of this research was to study how chemical and hydraulic signalling from the root system controlled gas exchange in a drying soil in quinoa. It was observed that during soil drying, relative g_s and photosynthesis A_max (drought stressed/fully watered plants) equalled 1, until the fraction of transpirable soil water (FTSW) decreased to 0.82 ± 0.152 and 0.33 ± 0.061, respectively, at bud formation, indicating that photosynthesis was maintained after stomata closure. The relationship between relative g_s and relative A_max at bud formation was represented by a logarithmic function (r² = 0.79), which resulted in a photosynthetic water use efficiency WUE_Amax_/gs$\text{WU}{\text{E}}_{A_{\text{max}}/g_{\text{s}}}$ of 1 when FTSW > 0.8, and increased by 50% with soil drying to FTSW 0.7–0.4. Mild soil drying slightly increased ABA in the xylem. It is concluded that during soil drying, quinoa plants have a sensitive stomatal closure, by which the plants are able to maintain leaf water potential (ψ_l) and A_max, resulting in an increase of WUE. Root originated ABA plays a role in stomata performance during soil drying. ABA regulation seems to be one of the mechanisms utilised by quinoa when facing drought inducing decrease of turgor of stomata guard cells.  相似文献   

In vitro multiplication of statice plantlets using sugar-free media     

Yulan Xiao  Toyoki Kozai 《Scientia Horticulturae》2006

Clumps of statice (Limonium latifolium) plantlets grown photomixotrophically were used as explants and cultured for 25 days on a sugar-free modified Murashige and Skoog (MS) medium in Magenta-type vessels with the number of air exchanges of the vessel (NAE) being 3.8 h⁻¹, at a photosynthetic photon flux (PPF) of 100 μmol m⁻² s⁻¹ and a CO₂ concentration of 1500 μmol mol⁻¹ in the culture room. A factorial experiment was conducted with three levels of 6-benzylaminopurine (BA) concentration, namely 0, 0.25 and 0.5 mg L⁻¹, and two types of supporting material, agar and Florialite (a porous material). The control treatment was a photomixotrophic culture using a sugar- and BA (0.25 mg L⁻¹) containing agar medium in the vessel with NAE of 0.2 h⁻¹, at a PPF of 50 μmol m⁻² s⁻¹ and a CO₂ concentration of 400 μmol mol⁻¹ in the culture room. Leaf area, chlorophyll concentration and net photosynthetic rate were greater in the sugar-free medium treatment with a BA concentration of 0.25 mg L⁻¹ and Florialite than those in the control treatment. The number of shoots and dry weight per clump in the sugar-free medium treatment were comparable to those in the control treatment. Among the sugar-free medium treatments, the number of shoots increased with increasing BA concentration, however, the leaf area, dry weight, chlorophyll concentration and net photosynthetic rate decreased with increasing BA concentration. The use of Florialite significantly enhanced the growth and root induction as well as net photosynthetic rate, compared with the treatments that use agar. These results indicated that sugar-free medium micropropagation could be commercially applied to the multiplication of statice plantlets.  相似文献   

Physiological and biochemical changes with special reference to mangiferin and oxidative enzymes level in malformation resistant and susceptible cultivars of mango (Mangifera indica L.)     

V.K. Singh 《Scientia Horticulturae》2006

Changes in biophysical attributes, mangiferin and polyphenol oxidase (PPO), catalase and peroxidase activities in malformation resistant mango cultivar Elaichi were studied at various stages of flower development and compared with susceptible cvs. Amrapali, Beauty Mc-lin and Dashehari. Accumulation of mangiferin was maximum (96.0 and 108.0 mg g⁻¹ FW) in Elaichi prior to flower bud differentiation (September) and at full bloom (February), while these were minimum (59.0 and 74.0 mg g⁻¹ FW) in susceptible cv. Beauty Mc-lin. Mangiferin promoted vegetative growth and exhibited inhibitory role on the occurrence of malformation. It was also found that the resistant cultivar had highest activity of PPO as compared to susceptible ones. There was no significant difference in the enzymes catalase and peroxidase activity at early stage of flower differentiation but at flower bud burst stage the catalase activity was enhanced significantly in cv. Elaichi (25.28 unit min⁻¹ g⁻¹ FW) in comparison to Amrapali (16.20 unit min⁻¹ g⁻¹ FW), Beauty Mc-lin (18.39 unit min⁻¹ g⁻¹ FW) and Dashehari (17.50 unit min⁻¹ g⁻¹ FW). The resistant cultivar had high leaf temperature (30.30 °C) and diffusion resistance (476.14 m mol m⁻² s⁻¹) during the flowering but the rate of transpiration and relative humidity (RH) were high in susceptible cultivars. Results of the present study clearly indicate that level of mangiferin could be considered as a potential biochemical indicator for screening mango genotypes to malformation.  相似文献   

In vitro proliferation from axillary buds and ex vitro protocol for effective propagation of Syringa × hyacinthiflora ‘Luo Lan Zi’     

Hongxia Cui  Xiaohong GuLei Shi 《Scientia Horticulturae》2009

As a precondition for lilac mass propagation, the optimal shoot-multiplication medium for Syringa × hyacinthiflora ‘Luo Lan Zi’ was ascertained mainly based on clustered microshoot inducement and large leaf area establishment in 6-benzyladenine (BAP) (1.00 mg L⁻¹) and zeatin (Z) (0.10 mg L⁻¹) combination. Medium supplied with lower level of BAP (0.50 mg L⁻¹) and auxin (IAA) (0.25 mg L⁻¹) was not suitable for lilac shoot proliferation, but it could be competent for long-term preservation of the un-rooted shoots so that subsequent proliferation culture could be carried out at anytime. In addition, excess height growth which resulted in low transplanting survival rate was effectively controlled by decrease in node number when paclobutrazol (PBZ) was applied in rooting medium at a concentration of 1.00 mg L⁻¹ after taking into account the effects on shoot height, rooting, persistent leaf area and PBZ carry-over. An important overwintering treatment was to use a plastic chamber covering for plants in the greenhouse prior to field planting to ensure adequate biomass of stem and underground parts not only in the current growing season but also in the subsequent years.  相似文献   

Molecular cloning and characterization of a cucumber MAP kinase gene in response to excess NO₃ and other abiotic stresses     

Huini Xu  Xiufeng Wang  Xudong Sun  Qinghua Shi  Fengjuan Yang  Dongliang Du 《Scientia Horticulturae》2008

Mitogen-activated protein kinases (MAPKs) play important roles in the transduction of extracellular signals to the intracellular targets in all eukaryotes. Here, a cucumber cDNA designated CsNMAPK, encoding a mitogen-activated protein kinase was isolated using RT-PCR, 3′ and 5′ RACE. The full-length cDNA sequence contains 1636 bp and an open reading frame (ORF) of 1113 bp, which encodes 370 amino acid residues. According to the phylogenetic analysis, CsNMAPK belongs to subgroup I MAPK in plants. Northern blot analysis revealed that CsNMAPK expressed differently in response to excess NO₃⁻. And the CsNMAPK expression kinetics between a salt-resistant cultivar (Xintaimici) and a salt-sensitive cultivar (Shennongchunwu) was slightly different under 182 mmol L⁻¹ NO₃⁻ treatment. The mRNA levels also increased after 24 h treatments with H₂O₂ and salicylic acid (SA), but decreased with abscisic acid (ABA) and low-temperature. However, there was no significant induction of CsNMAPK gene after 24 h drought and high-temperature treatments. Our results suggested that a MAP kinase cascade may function in excess NO₃⁻ and other abiotic stresses in cucumber.  相似文献   

H₂O₂ metabolism during sweet orange (Citrus sinensis L. Osb.) ‘Hamlin’ Xanthomonas axonopodis pv. citri interaction     

Naveen Kumar  Robert C. EbelPamela D. Roberts 《Scientia Horticulturae》2011

Sweet orange (Citrus sinensis L. Osb.) ‘Hamlin’ is a canker (Xanthomonas axonopodis pv. citri: Xac) susceptible citrus genotype grown commercially worldwide. Canker causes severe economic losses and restricts the marketability of crop for export. Little is known about the role of oxidative stress in canker development. In the present investigation, sweet orange ‘Hamlin’ leaves were artificially inoculated with Xac to determine the impact of Xac infection on hydrogen peroxide (H₂O₂) metabolism. Characteristic symptoms following artificial inoculation were water soaking of the infiltrated zone between 2 and 8 days after inoculation (dai); raised epidermis accompanying tiny yellow colored bacterial colonies at 8 dai; and yellowing and necrosis of the infected zone by 12–16 dai. In planta Xac population increased 1000 fold by 14 dai from an initial population of 7.3 × 10⁶ cfu cm⁻² (0 dai). Peak concentrations of H₂O₂ were observed at 24 h and between 8 and 10 dai and coincided with higher activity of total superoxide dismutase (SOD). Lower levels of H₂O₂ in infected leaves were maintained by Xac induced higher activities of catalase (CAT), ascorbate peroxidase (APOD), and guaiacol peroxidase (POD). It appears Xac altered H₂O₂ metabolism in C. sinensis L. Osb. ‘Hamlin’ to enhance survival and growth.  相似文献   

Variation in stomatal behaviour and gas exchange between mid-morning and mid-afternoon of north–south oriented grapevines (Vitis vinifera L. cv. Tempranillo) at different levels of soil water availability     

E. Cuevas  P. BaezaJ.R. Lissarrague 《Scientia Horticulturae》2006

A 3-year study was conducted to examine leaf gas exchange response of Vitis vinifera L. (cv. Tempranillo) grapevines growing in the central Iberian Peninsula as a function of soil water availability. Net CO₂ assimilation rate (A), stomatal conductance (g_s) and transpiration (E) of leaves were measured at the east and west side of vines planted in north/south orientated rows. Soil water availability was varied by three different irrigation treatments at 0.45, 0.30 and 0.15 of ETo and a fourth non-irrigated treatment. Approximately 60% of the variation in g_s over 3 years was due to changes in soil water content (θ_v); the correlation between the two was closer when examined on a season by season basis. Net CO₂ assimilation rates were significantly correlated with g_s. Stomatal conductance decreased by approximately 25–30% when measured 15:00 h (west side of vines) compared to 09:00 h (east side of vines); reductions in A were even greater than those in g_s. Leaf E increased approximately by 15–25% from morning to afternoon. The reduction in A and g_s from morning to afternoon was observed even in irrigated vines but absolute differences increased with decreasing soil water. This occurred when maximum daily g_s was less than 200 mmol m⁻² s⁻¹. These responses indicate that in hot areas training systems and row orientation, which minimize exposed leaf, area in the afternoon should be recommended.  相似文献   

Responses of cucumber plant to NH₄ and NO₃ nutrition: The relative addition rate technique vs. cultivation at constant nitrogen concentration     

Hamid R. Roosta  Abdoreza Sajjadinia  Asghar Rahimi  Jan K. Schjoerring 《Scientia Horticulturae》2009

Different N sources (NO₃⁻, NH₄⁺, or NH₄NO₃) at different relative addition rates (RAR) were supplied to cucumber (Cucumis sativus L.), a species sensitive to NH₄⁺ toxicity. For comparison, cucumber plants were also grown at constant concentrations of 1 and 5 mM NH₄⁺ or 5 mM NO₃⁻. The fresh weight of NH₄⁺-fed plants at RAR 0.15 and RAR 0.25 day⁻¹ was similar to that of NO₃⁻-fed plants, while at RAR 0.35 or RAR 0.45 day⁻¹ growth reduction occurred. When available as a constant concentration, NH₄⁺ decreased plant growth at 5 mM. It is concluded that at low rates of N supply the relative addition rate technique can be used for growing cucumber plants with NH₄⁺ as sole N source without deleterious effects.  相似文献   

Growth characteristic and sink strength of fruit at different CO₂ concentrations in a Japanese and a Dutch tomato cultivar     

Ryo Matsuda  Akimasa Nakano  Dong-Hyuk AhnKatsumi Suzuki  Ken-Ichiro YasubaMasuyuki Takaichi 《Scientia Horticulturae》2011

The aim of the present study was to elucidate how fruit growth was limited by the source and sink capacities in a Japanese (‘Momotaro York’) and a Dutch (‘Dundee’) tomato cultivar. The two cultivars were grown hydroponically with a high-wire system in greenhouses for 25 weeks, and the growth characteristics and sink strength of fruit were determined. Fruits were pruned to four (4F) or one (1F) per truss. The latter were used to determine potential fruit growth, an indicator of fruit sink strength. Growth was also determined under normal (LC) and enriched (HC, 700 μmol mol⁻¹) CO₂ concentrations to examine the effect of source enhancement on fruit production. In both cultivars under normal CO₂, the growth rate of fruit pruned to 4F per truss was lower than that in 1F, indicating that maximum potential fruit growth was not achieved. Under HC conditions, fruit growth rate of ‘Dundee’ achieved in 4F trusses was lower than that in 1F. In ‘Momotaro York’ in HC, fruit growth in 4F trusses was close to potential. This implies that fruit growth was source-limited irrespective of CO₂ concentrations in ‘Dundee’ cultivar while fruit growth in ‘Momotaro York’ under normal and enriched CO₂ conditions was limited by source and sink strengths, respectively. Adjustments of cultural practices including increasing fruit number per truss and/or genetic approaches to enhancing fruit sink strength by breeding may improve fruit yields of Japanese cultivars under high source/sink conditions.  相似文献   

Cucumber fruit quality at harvest affected by soilless system,crop age and preharvest climatic conditions during two consecutive seasons     

M.D. Gómez-López  J.P. Fernández-Trujillo  A. Baille 《Scientia Horticulturae》2006

Cucumber fruits (Cucumis sativus L., cv. Trópico F1) grown on perlite substrate and NFT (Nutrient Film Technique) were harvested during two seasons (winter and spring) to monitor the effects of climatic conditions and hydroponic growth systems on fruit quality at harvest. The best fruit quality at harvest, as measured by lightness and hue angle parameters, was obtained during the 3 weeks following the first winter picking. When values of a parameter of preharvest climate value called G^* were lower than 0.4 MJ m⁻² °C day⁻¹ interval⁻¹, the cucumber achieved its optimum quality at harvest, as measured by the dark green color of the skin. NFT-grown fruits showed darker and greener skin color (higher hue angle and lower lightness) compared with perlite-grown fruit, irrespective of the season considered. During the winter season, the plant transpiration rate was 30% higher in perlite than in NFT culture, which correlates with higher differences in G^* and 40% additional yield in perlite. However, in spring G^* was not sensitive enough to discriminate between the two hydroponic systems. In general, fruit quality at harvest in spring was lower than during the winter, due to flesh whitening, higher longitudinal and equatorial calibers, and slightly higher pH, as well as worse epidermal color coordinates (ranging from the dark and dull green color typical of winter fruit to light and a vivid green-yellow color). During the spring season, NFT-grown fruit were less acid than perlite-grown fruit with no apparent correlation with the climatic conditions or fruit nutrition.  相似文献   

Sennoside content and yield attributes of Cassia angustifolia Vahl. as affected by NaCl and CaCl₂     

A. Arshi  M.Z. Abdin  M. Iqbal 《Scientia Horticulturae》2006

Pot culture experiments were conducted to assess the extent of growth, photosynthetic capacity, sennoside concentration and yield attributes of Senna plant under the individual as well as combined influence of NaCl and CaCl₂. Six treatments, i.e. NaCl (80 and 160 mM), CaCl₂ (5 and 10 mM) alone and a combination of NaCl + CaCl₂ (80 + 10 and 160 + 10 mM) were given to the growing Senna plants at pre-flowering (45 DAS), flowering (75 DAS) and post-flowering (90 DAS) stages. Significant reductions were observed in pod biomass, leaf area, stomatal conductance, photosynthetic rate and sennoside concentration and yield, with each NaCl treatment. On the contrary, individual CaCl₂ treatments had a favourable effect. Under the effect of combination treatments, although these parameters were reduced, the extent of reduction was much less than one caused by NaCl treatments. The combined treatments thus mitigated the adverse effects caused by NaCl.  相似文献   

The effects of foliar applied CaCl₂·2H₂O,Ca(OH)₂ and K₂CO₃ combined with the surfactants Glucopon and Plantacare on gas exchange of 1 year old apple (Malus domestica BORKH.) and broad bean (Vicia faba L.) leaves     

R.Q. Bai  T.K. Schlegel  J. Schönherr  P.W. Masinde 《Scientia Horticulturae》2008

Calcium chloride, calcium hydroxide, potassium carbonate and the alkylpolyglycoside surfactants Glucopon 215 CSUP and Plantacare 12 UP are salts applied to leaves as foliar nutrients and fungicides. These chemicals were sprayed on apple (Malus domestica BORKH.) and broad bean (Vicia faba L.) leaves. Stomatal conductance and rates of net photosynthesis were measured continuously in the light and in the dark using a Portable Photosynthesis System CIRAS-1. All compounds with the exception of Ca(OH)₂ affected stomatal conductance and net photosynthesis, albeit to different degrees. In light, Plantacare either alone (0.2 g l⁻¹) or in combination with CaCl₂·2H₂O (5 g l⁻¹) or K₂CO₃ (5 g l⁻¹) caused a rapid initial increase in stomatal conductance during the first 1–3 h after spraying on the leaves, maximum conductances were observed about 6 h after application. A rather high stomatal conductance was observed during the dark period when Glucopon (0.2 g l⁻¹) was applied either alone or in combination with Ca(OH)₂. The combination CaCl₂·2H₂O + Glucopon did not cause this elevated stomatal conductance during the dark. CaCl₂·2H₂O reduced stomatal conductance in combination with both Glucopon and Plantacare. The surfactant Plantacare reduced net photosynthesis during the first light period (12 h), if applied alone or in combination with CaCl₂·2H₂O. Treatment of broad bean leaves with K₂CO₃ + Plantacare resulted in a rapid decrease in net photosynthesis during the first hour, and then the rates of net photosynthesis increased rapidly and approached to those of the water control. The effects of surfactants and salts on net photosynthesis had nearly disappeared by the beginning of the second light period. Non-specific glycosidases presumably cleaved the glycosidic bond between the alkyl and the sugar moieties during the preceding night. Our data showed that foliar applications of CaCl₂·2H₂O and K₂CO₃ together with alkyl polyglycoside surfactants can affect gas exchange. However, the effects of the chemicals at the concentrations used in our study were not very large and were transient. They practically vanished within 24 h and a detrimental effect on growth and development of crops was not likely.  相似文献   

Photosynthetic and growth responses of juvenile Chinese kale (Brassica oleracea var. alboglabra) and Caisin (Brassica rapa subsp. parachinensis) to waterlogging and water deficit     

Montree Issarakraisila  Qifu Ma  David W. Turner 《Scientia Horticulturae》2007

Chinese kale (Brassica oleracea var. alboglabra) and Caisin (Brassica rapa subsp. parachinensis) are leafy vegetable crops grown in south-east Asian countries where rainfall varies dramatically from excess to deficit within and between seasons. We investigated the physiological and growth responses of these plants to waterlogging and water deficit in a controlled experiment in a glasshouse. Juvenile plants were subjected to waterlogging or water deficit for 19 days in case of Chinese kale and 14 days in case of Caisin and compared with well-watered controls. Caisin tolerated waterlogging better than Chinese kale because it produced hypocotyl roots and gas spaces developed at the stem base. In Chinese kale, waterlogging reduced plant fresh weight (90%), leaf area (86%), dry weight (80%) and leaf number (38%). In contrast, waterlogging had no impact on leaf number in Caisin and reduced plant fresh and dry weights and leaf area by 60–70%. Water deficit reduced leaf area, fresh weight and dry weight of both species by more than half. Leaf number in Chinese kale was reduced by 38% but no effect occurred in Caisin. Water deficit increased the concentration of nitrogen in the leaf dry matter by more than 60% in both species and the leaf colour of water deficient plants was dark green compared with the leaf colour of well-watered plants. Soil water deficit delayed flowering of Caisin while waterlogging accelerated it. Thickening and whitening of the cuticle on the leaves of Chinese kale probably increased its ability to retain water under drought while Caisin adjusted osmotically and Chinese kale did not. Waterlogging and water deficit had strong effects on leaf gas exchange of both Brassica species. Water deficit closed the stomata in both species and this was associated with a leaf water content of 9 g g⁻¹ DW. In contrast, waterlogging reduced conductance from 1.0 to 0.1 mol H₂O m⁻² s⁻¹ in direct proportion to changes in leaf water content, which fell from 11 to 5 g g⁻¹ DW. This separation of the effects of water deficit and waterlogging on conductance was reflected in transpiration, internal CO₂ concentration and net photosynthesis. In conclusion, Chinese kale and Caisin showed rather different adaptations in response to waterlogging and water deficit. Caisin was more tolerant of waterlogging than Chinese kale and also showed evidence of tolerance of drought. There is genetic variation to waterlogging within the Brassica genus among the leafy vegetables that could be used for cultivar improvement.  相似文献   

Direct regeneration of plants derived from in vitro cultured shoot tips and leaves of three Lysimachia species     

Wei Zheng  Xiao-Dan XuHuan Dai  Long-Qing Chen 《Scientia Horticulturae》2009

The regenerability of three ornamental species—Lysimachia christinae, Lysimachia rubinervis and Lysimachia nummularia ‘Aurea’, were investigated using in vitro leaves and shoot tips. 6-Benzylaminopurine (BAP) and α-naphthalene acetic acid (NAA) added to Murashige and Skoog (MS) medium were tested for their effect on organogenesis. On the medium, shoot regeneration occurred directly without callus formation. In these species, L. christinae developed the highest regeneration rate and numbers of shoots/explant from shoot tips (100%, 12.25) and leaf bases (100%, 13.01) on the MS medium containing 3.0 mg l⁻¹ BAP and 0.1 mg l⁻¹ NAA. For L. rubinervis, the highest shoot induction rate and number of shoots/explant were obtained from shoot tip (100%, 16.87–17.20) on the MS medium with 0.1 mg l⁻¹ NAA and 3.0–5.0 mg l⁻¹ BAP. L. nummularia ‘Aurea’, however, showed the highest regeneration rate and number of shoots/explant (100%, 12.73) from leaf bases on MS medium supplemented with 1.0 mg l⁻¹ BAP and 0.1 mg l⁻¹ NAA. All in vitro shoots rooted well on half macronutrient MS medium containing 0.1 mg l⁻¹ NAA. After acclimatization, transplanted plantlets grew normally and flowered in the field.  相似文献   

Production of inter-section hybrids between Primula filchnerae and P. sinensis through ovule culture     

Junji Amano  Juntaro Kato  Masaru Nakano  Masahiro Mii 《Scientia Horticulturae》2006

Inter-section hybrids were obtained in the reciprocal crosses between Primula filchnerae (2n = 2x = 24) of Sect. Pinnatae and P. sinensis ‘Fanfare’ (2n = 2x = 24) of Sect. Auganthus by rescuing ovules on half-strength (1/2) Murashige and Skoog's (MS) medium supplemented with 50 g l⁻¹ sucrose, 2.5 g l⁻¹ gellan gum, 0.1 mg l⁻¹ α-naphthaleneacetic acid (NAA), 0.1 mg l⁻¹ 6-benzyladenine (BA) and 50 mg l⁻¹ gibberellic acid (GA₃). In ovule culture, germination occurred with radicle elongation but no plumule was observed. The radicle kept on the initial medium showed root proliferation with callus formation. When the calluses were transferred to (1/2)MS media containing 30 g l⁻¹ sucrose and 3 g l⁻¹ gellan gum, without plant growth regulators (PGRs) or with 1 mg l⁻¹ zeatin and 0.1 mg l⁻¹ NAA, plantlets were regenerated. The plants thus obtained were confirmed to be hybrids through flow cytometry (FCM) and random amplified polymorphic DNA (RAPD) analyses. The hybrid obtained when P. filchnerae was used as the maternal parent was diploid, whereas hexaploid hybrid was obtained when using P. sinensis as the maternal parent. The hexaploid hybrid might be produced through chromosome doubling of a triploid originated from the fertilization of P. sinensis with unreduced pollen of P. filchnerae.  相似文献