Comparative effect of 28-homobrassinolide and 24-epibrassinolide on the growth,carbonic anhydrase activity and photosynthetic efficiency of <Emphasis Type="Italic">Lycopersicon esculentum</Emphasis>

The present piece of work highlights the comparative effects of two active forms of brassinosteroids (BRs), 28-homobrassinolide (HBL) and 24-epibrassinolide (EBL), on growth parameters, carbonic anhydrase activity and photosynthetic parameters in Lycopersicon esculentum (cv. K-21) sampled at 45 (24 h after spray) and 60 days after sowing, under natural conditions. Out of the two active forms of BR, EBL proved better than HBL in improving the above parameters, when applied as foliar spray. Of the three concentrations (10⁻⁶ M, 10⁻⁸ M or 10⁻¹⁰ M) of HBL and EBL, 10⁻⁸M proved best in both cases.     

Gravitropic reaction of primary seminal roots ofZea mays L. influenced by temperature and soil water potential

The growth of the primary seminal root of maize (Zea mays L.) is characterized by an initial negative gravitropic reaction and a later positive one that attains a plagiotropic liminal angle. The effects of temperature and water potential of the surrounding soil on these gravitropic reactions were studied. Temperatures of 32, 25, and 18C and soil water potentials of −5,−38, and −67 kPa were imposed and the direction of growth was measured for every 1 cm length of the root. The initial negative gravitropic reaction extended to a distance of about 10cm from the graln. Higher temperatures reduced the initial negative gravitropic reaction. Lower soil water potential induced a downward growth at root emergence. A mathematical model, in which it was assumed that the rate of the directional change of root growth was a sum of a time-dependent negative gravitropic reaction and an establishment of the liminal angle, adequately fitted the distance-angle relations. It was suggested that higher temperatures and/or a lower water potential accelerated the diminution of the intitial negative gravitropic reaction.     

Interactive effect of nitric oxide and brassinosteroids on photosynthesis and the antioxidant system of <Emphasis Type="Italic">Lycopersicon esculentum</Emphasis>

An interactive effect of nitric oxide and 24-epibrassinolide (EBL) or 28-homobrassinolide (HBL) was investigated in Lycopersicon esculentum Mill. cv. K-21. Seeds prior to sowing were exposed to sodium nitroprusside (SNP) (0, 10⁻⁵ M or 1 M), a nitric oxide donor, for 8 h, and the resulting seedlings were subsequently sprayed with 10⁻⁸ M EBL or HBL at 30-day stage. The analysis of plant samples after 24 h of the EBL or HBL spray showed that the lower SNP concentration (10⁻⁵ M) favored the growth, pigment content, photosynthetic and enzymatic activities, and also improved the antioxidant system. However, 1 M SNP had inhibitory impact on most of the indices, except the antioxidant system. Brassinosteroids (EBL or HBL), on the other hand, had a stimulatory impact on the aforementioned indices. The inhibitory effect of SNP (1 M) was neutralized by the application of BRs, where EBL was more effective than HBL.     

Effects of fluridone and abscisic acid on lateral root initiation and root elongation of excised tomato roots cultured in vitro

Roots of tomato (Lycopersicon esculentum Mill. cv. Bonny Best) were excised and cultured in the presence of the abscisic acid synthesis inhibitor fluridone, and with concentrations of exogenous abscisic acid ranging from 10⁻¹⁰to 10⁻⁴M to determine the effects of abscisic acid and its synthesis inhibition on the development of lateral roots in in vitro cultured tomato roots. Exogenous abscisic acid inhibited lateral root initiation and emergence at concentrations of 10⁻⁶M and greater. Fluridone (10⁻⁶M) enhanced the formation of lateral roots even in the presence of abscisic acid, at all concentrations tested except 10⁻⁴M. Abscisic acid increased apical distance, and fluridone reduced it up to 10⁻⁵M abscisic acid. Both fluridone and abscisic acid reduced lateral and primary root lengths. It was concluded the endogenous abscisic acid is probably involved in the regulation of lateral root initiation and root apical dominance, and that abscisic acid may affect lateral root initiation differently than lateral root emergence. This revised version was published online in June 2006 with corrections to the Cover Date.     

The effect of plant growth regulators on formation of crown gall tumors on potato tuber discs

The effect of several plant growth regulators on the number of tumors developing on potato tuber discs (Solatium tuberosum L. cv. Radka) inoculated withAgrobacterium tumefaciens, strain C 58 was studied. The plant growth regulators used in appropriate range of concentrations stimulated the formation of tumors byA. tumefaciens. Naphthaleneacetic acid (NAA) was most active in concentration of 10⁻⁴ mg ml⁻¹. Kinetin gave a biphasic response with optimal promotions of tumor initiation at 10⁻⁴ − 2 × 10⁻³ mg ml⁻¹. High kinetin concentration (10⁻¹ mg ml⁻¹) inhibited the formation of tumors completely. Indoleacetic acid (IAA) stimulated the initiation of tumors in the same range of concentrations as kinetin, except that very high concentrations did not inhibit but enhanced tumor formation. 2,4-diehlorphenoxyacetic acid (2,4-D) showed a biphasic response with maxima in 10⁻⁴ mg ml⁻¹ and 10⁻¹ mg ml⁻¹. All the tumors scored for nopaline production showed nopaline synthase activity independently whether their formation was stimulated by l0⁻¹ mg ml⁻¹ IAA or they were initiated without any treatment by plant growth regulators.     

Enhancing effects of 24-epibrassinolide and Putrescine on the antioxidant capacity and free radical scavenging activity of <Emphasis Type="Italic">Raphanus sativus</Emphasis> seedlings under Cu ion stress

The present investigation recorded significant restoration of seedling growth (root length, shoot length and fresh weight) upon application of 24-epibrassinolide (EBL) and putrescine (Put) to 7-day-old seedlings of Raphanus sativus L. cv. Pusa chetki grown under copper (Cu) ion stress. EBL and Put with/or without Cu ion treated seedlings showed increased titers of ascorbic acid, total phenols and proline when compared with Cu-stressed seedlings. Differential responses in the activities of guaiacol peroxidase (GPOX) and catalase (CAT) were noted for EBL and Put alone or with/or without Cu ion treatment. Decreased activities of glutathione reductase (GR) and superoxide dismutase (SOD) noted for EBL and Put alone were observed to enhance significantly when applied in combination with Cu ion solution. A remarkable decrease in malondialdehyde contents was observed in seedlings treated with EBL and Put alone and with/or without Cu ion stress. Enhanced free radical scavenging activities were also recorded for seedlings given EBL and Put alone or in combination over Cu ion stressed seedlings. Maximum DPPH activity was observed in seedlings treated with Put and EBL 10⁻⁹ M + Put. Significant enhancements in deoxyribose and reducing power activities were too recorded for Put, EBL and Put + 10⁻⁹ M EBL treatments. Improved seedling growth, antioxidant levels (ascorbic acid, total phenols and proline) and enzymic (GPOX, CAT, SOD and GR) activities and free radical scavenging capacities along with reduced membrane damage in seedlings given EBL and Put with/or without Cu stress suggests significant and positive interactions of EBL and Put in alleviating the Cu ion induced oxidative damage in radish seedlings.     

Improved <Emphasis Type="Italic">in vitro</Emphasis> micropropagation method with adventitious corms and roots for endangered saffron

The objective of this study was to investigate development of an efficient in vitro tissue culture system for saffron (Crocus sativus L.) complete with roots and corms. In indirect organogenesis, Murashige and Skoog (MS) media with 3% (w/v) sucrose, 100 mg L⁻¹ ascorbic acid, and the combination of 0.25 mg L⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D) and 1 mg L⁻¹ 6-benzylaminopurine (BAP) were best for callus initiation and growth while 1.5 mg L⁻¹ BAP was excellent for high rate of adventitious shoot formation. 1 mg L⁻¹ indole-3-butyric acid (IBA) was more preferable for adventitious corm and root initiation as well as growth. Overall, 64% rooting and 33% corm production rates were achieved in indirect organogenesis. In direct organogenesis, MS medium supplemented with 3 % sucrose, 100 mg L⁻¹ ascorbic acid and 1 mg L⁻¹ BAP was optimum for shoot growth. While 1 mg L⁻¹ IBA was best for adventitious corm formation, 2 mg L⁻¹ IBA promoted adventitious root initiation and growth. Overall, 36% and 57% of explants had corm and contractile root, respectively. The high rates suggest that efficient tissue culture system could be achieved for mass propagation and ex situ conservation of threatened saffron genetic resources.     

Photoperceptive Site of the Photoinduction of Root Hairs in Lettuce (Lactuca sativa L. cv. Grand Rapids) Seedlings Under Low pH Conditions

Lactuca sativa L. cv. Grand Rapids) seedlings under acidic conditions by a phytochrome-mediated response. Microbeam irradiation of 1 mm root segments with the first (100 Jm⁻²) and second (1,000 Jm⁻²) maxima of the fluence response curve for red light induction of root hair initiation indicated that the ca. 5 mm apical portion of 12 mm long roots was the site of photoperception. The root hair-forming portion of the root was situated at a distance of 1.7 mm from the root tip at the time of red light irradiation and extended (at most 1.5 mm) towards the basal end at a later stage of development, irrespective of which portion of the root was irradiated with red light. Received 13 August 1999/ Accepted in revised form 22 December 1999     

Effect of Agar, MS Medium Strength, Sucrose and Polyamines on in vitro Rooting of Syzygium Alternifolium

This paper describes the effect of agar, MS basal medium strength, sucrose and polyamines on the in vitro rooting of Syzygium alternifolium realized by a two step procedure involving root initiation (RI) and root elongation (RE). RI was carried out on solidified MS medium supplemented with 1.0 mg dm⁻³ indole-3-butyric acid (IBA) for 3 weeks, and RE following transfer to half-strength MS medium devoid of growth regulators for another 3 weeks. Agar and MS basal medium concentrations played important role on rooting response as well as on health of rooted shoots. Sucrose concentration was positively correlated with the rooting percentage, root number per shoot and root length. The combination of polyamines and 1.0 mg dm⁻³ IBA increases rooting percentage compared to media containing only 1.0 mg dm⁻³ IBA. Optimum rooting was attained with half-strength MS medium containing 1.0 mg dm⁻³ IBA, 2 % sucrose, 10 μM spermine and 0.8 % agar. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of Cadmium on Root Growth, Cell Division and Nucleoli in Root Tip Cells of Garlic

The effects of different concentrations (10⁻⁷ to 10⁻² M) of cadmium chloride on root growth, cell division and nucleoli in root tip cells of Allium sativum L. were investigated. At lower concentrations of Cd²⁺ (10⁻⁷ to 10⁻⁶ M), Cd²⁺ did not influence the root growth, even had a stimulation effects during a short treatment. The results showed that the rate of root growth per day at the treatment groups (10⁻⁴ to 10⁻² M Cd²⁺) decreased with increasing duration of the treatment and increasing Cd²⁺ concentration. Cd²⁺ induced c-mitosis, anaphase bridges, chromosome stickiness and on nucleoli, causing some particles of similar silver-stained material scattered in the nuclei and making the silver staining reaction at the periphery of the nucleolus weaker. This revised version was published online in July 2006 with corrections to the Cover Date.     

Salicylic acid can regulate phloem unloading in the root tip

In three-day-old maize (Zea mays L.) seedlings, we removed the endosperm, coleoptile with leaflets, and adventitious roots. Primary roots were exposed to 0–10⁻³ M salicylic acid (SA) for 1–5 h; scutellum, to 10⁻² M 2-desoxy-D-glucose (2dG). 2dG-sucrose synthesized from 2dG was transported from scutella to the roots along the phloem. Its accumulation in 5-mm-long root tips was the measure of phloem unloading. At the concentrations higher than 10⁻⁴ M, SA suppressed unloading. Simultaneously, the uptake of ¹⁴C-5,5-dimethyloxazolidinedione (DMO) by root segments was inhibited, indicating cytoplasm acidification. 10⁻³ M SA also inhibited root respiration and growth. The lower SA concentrations (10⁻⁵ and 10⁻⁶ M) activated unloading under conditions of weak sucrose phloem transport to the root. They did not affect DMO uptake, respiration, and growth. 10⁻⁴ M SA stimulated unloading during 1- or 2-h exposure but did not affect it at longer treatments. A dependence of SA action on its concentration and exposure duration implies its involvement in the control of phloem unloading in the root tip.     

Seasonal dynamics of fine root biomass, root length density, specific root length, and soil resource availability in a Larix gmelinii plantation

Fine root turnover is a major pathway for carbon and nutrient cycling in terrestrial ecosystems and is most likely sensitive to many global change factors. Despite the importance of fine root turnover in plant C allocation and nutrient cycling dynamics and the tremendous research efforts in the past, our understanding of it remains limited. This is because the dynamics processes associated with soil resources availability are still poorly understood. Soil moisture, temperature, and available nitrogen are the most important soil characteristics that impact fine root growth and mortality at both the individual root branch and at the ecosystem level. In temperate forest ecosystems, seasonal changes of soil resource availability will alter the pattern of carbon allocation to belowground. Therefore, fine root biomass, root length density (RLD) and specific root length (SRL) vary during the growing season. Studying seasonal changes of fine root biomass, RLD, and SRL associated with soil resource availability will help us understand the mechanistic controls of carbon to fine root longevity and turnover. The objective of this study was to understand whether seasonal variations of fine root biomass, RLD and SRL were associated with soil resource availability, such as moisture, temperature, and nitrogen, and to understand how these soil components impact fine root dynamics in Larix gmelinii plantation. We used a soil coring method to obtain fine root samples (⩽2 mm in diameter) every month from May to October in 2002 from a 17-year-old L. gmelinii plantation in Maoershan Experiment Station, Northeast Forestry University, China. Seventy-two soil cores (inside diameter 60 mm; depth intervals: 0–10 cm, 10–20 cm, 20–30 cm) were sampled randomly from three replicates 25 m × 30 m plots to estimate fine root biomass (live and dead), and calculate RLD and SRL. Soil moisture, temperature, and nitrogen (ammonia and nitrates) at three depth intervals were also analyzed in these plots. Results showed that the average standing fine root biomass (live and dead) was 189.1 g·m⁻²·a⁻¹, 50% (95.4 g·m⁻²·a⁻¹) in the surface soil layer (0–10 cm), 33% (61.5 g·m⁻²·a⁻¹), 17% (32.2 g·m⁻²·a⁻¹) in the middle (10–20 cm) and deep layer (20–30cm), respectively. Live and dead fine root biomass was the highest from May to July and in September, but lower in August and October. The live fine root biomass decreased and dead biomass increased during the growing season. Mean RLD (7,411.56 m·m⁻³·a⁻¹) and SRL (10.83 m·g⁻¹·a⁻¹) in the surface layer were higher than RLD (1 474.68 m·m⁻³·a⁻¹) and SRL (8.56 m·g⁻¹·a⁻¹) in the deep soil layer. RLD and SRL in May were the highest (10 621.45 m·m⁻³ and 14.83m·g⁻¹) compared with those in the other months, and RLD was the lowest in September (2 198.20 m·m⁻³) and SRL in October (3.77 m·g⁻¹). Seasonal dynamics of fine root biomass, RLD, and SRL showed a close relationship with changes in soil moisture, temperature, and nitrogen availability. To a lesser extent, the temperature could be determined by regression analysis. Fine roots in the upper soil layer have a function of absorbing moisture and nutrients, while the main function of deeper soil may be moisture uptake rather than nutrient acquisition. Therefore, carbon allocation to roots in the upper soil layer and deeper soil layer was different. Multiple regression analysis showed that variation in soil resource availability could explain 71–73% of the seasonal variation of RLD and SRL and 58% of the variation in fine root biomass. These results suggested a greater metabolic activity of fine roots living in soil with higher resource availability, which resulted in an increased allocation of carbohydrate to these roots, but a lower allocation of carbohydrate to those in soil with lower resource availability. __________ Translated from Acta Phytoecologica Sinica, 2005, 29(3): 403–410 [译自: 植物生态学报, 2005, 29(3): 403–410]     

Effects of Brassinolide with Naphthalene Acetic Acid on the Formation of Adventitious Roots,Trichome-Like Roots and Calli from Cultured Tobacco Leaf Segments,and the Expression Patterns of <Emphasis Type="Italic">CNT103</Emphasis>

We treated cultured tobacco leaf segments with brassinolide (BL) and naphthalene acetic acid (NAA) and determined that optimum concentrations of NAA for adventitious root, trichome-like root, and calli formation were, respectively, 10⁻⁶, 10⁻⁵, and 10⁻⁴ M. In the adventitious root formation group, the number and length of adventitious roots were increased at lower concentrations of BL; however, they became trichome-like roots at higher levels of BL. The trichome-like root formation group showed better development when a low concentration of BL was added. However, at higher concentrations of BL, trichome-like root production was reduced, forming calli instead. In the calli formation group, more calli were formed at low BL concentrations and after persistent exposure to BL regardless of BL concentration, and the size of the leaf segments increased. The CNT103 gene, which is expressed at the root tips showed increased levels of expression at BL concentrations up to 10⁻⁹ M and decreased levels of expression at BL concentrations over 10⁻⁹ M in the adventitious roots, trichome-like roots, and calli formation groups.     

Effects of hygromycin on cotton cultures and its application in <Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated cotton transformation

We have evaluated the effects of the antibiotic hygromycin B on cotton (Gossypium hirsutum L.) callus induction, callus proliferation, and seed germination. Nontransgenic cotyledon and hypocotyl showed obvious variance in tolerance to hygromycin. Cotyledons were more sensitive to hygromycin than hypocotyls. Hygromycin at 7.5 and 20 mg l⁻¹ completely inhibited callus initiation from cotyledon and hypocotyl explants, respectively. Nontransformed calli did not grow on media supplemented with 10 mg l⁻¹ hygromycin and were killed at 15 mg l⁻¹. In seed germination assay, the presence of 20 mg l⁻¹ hygromycin significantly suppressed shoot and root elongation of seedlings. This hygromycin concentration was applied to select regenerated transgenic plantlets and their progenies. Based on these results, we developed an efficient hygromycin selection protocol for Agrobacterium-mediated cotton transformation and regeneration.     

The tropic response of plant roots to oxygen: oxytropism in Pisum sativum L.

Plant roots are known to orient growth through the soil by gravitropism, hydrotropism, and thigmotropism. Recent observations of plant roots that developed in a microgravity environment in space suggested that plant roots may also orient their growth toward oxygen (oxytropism). Using garden pea (Pisum sativum L. cv. Weibul's Apollo) and an agravitropic mutant (cv. Ageotropum), root oxytropism was studied in the controlled environment of a microrhizotron. A series of channels in the microrhizotron allowed establishment of an oxygen gradient of 0.8 mmol · mol⁻¹ · mm⁻¹. Curvature of seedling roots was determined prior to freezing the roots for subsequent spectrophotometric determinations of alcohol dehydrogenase activity. Oxytropic curvature was observed all along the gradient in both cultivars of pea. The normal gravitropic cultivar showed a maximal curvature of 45° after 48 h, while the agravitropic mutant curved to 90°. In each cultivar, the amount of curvature declined as the oxygen concentration decreased, and was linearly related to the root elongation rate. Since oxytropic curvature occurred in roots exposed to oxygen concentrations that were not low enough to induce the hypoxically responsive protein alcohol dehydrogenase, we suspect that the oxygen sensor associated with oxytropism does not control the induction of hypoxic metabolism. Our results indicate that oxygen can play a critical role in determining root orientation as well as impacting root metabolic status. Oxytropism allows roots to avoid oxygen-deprived soil strata and may also be the basis of an auto-avoidance mechanism, decreasing the competition between roots for water and nutrients as well as oxygen. Received: 14 January 1998 / Accepted: 10 February 1998     

In vitro culture of Gypsophila paniculata L. and random amplified polymorphic DNA analysis of the propagated plants

A protocol is established for regeneration of the economically important cut flower plant, Gypsophila paniculata L., using shoot tips explants. Multiple shoots were obtained on Murashige and Skoog medium fortified with 0.5 mg dm⁻³ each of α-naphthaleneacetic acid and 6-benzyladenine. Addition of 10 g dm⁻³ agar promoted shoot proliferation and reduced the degree of shoot vitrification. Transfer to 3 mg dm⁻³ indole⁻³-butyric acid containing medium produced optimum root initiation and development. The produced plants as well as intact plants were subjected to the random amplified polymorphic DNA (RAPD) analysis. Using 9 primers, the total number of amplification products generated by polymerase chain reaction was 142 bands (15.7 bands per primer), of which 7.74 % showed polymorphism. The analysis of bands recorded, showed 92.25 % similarity. The results indicated that very low variation at the DNA level occurred during in vitro culture of Gypsophila.     

Effect of bicarbonate on root growth and accumulation of organic acids in Zn-inefficient and Zn-efficient rice cultivars (Oryza sativa L.)

Bicarbonate has been regarded as a major factor for inducing Zn deficiency in lowland rice, but the mechanisms responsible for this effect are not yet fully understood. The objective of the present study was to test whether early effects of bicarbonate (HCO₃ ⁻)are inhibition of root growth due to the accumulation of organic acids induced by HCO₃ ⁻. Solution culture experiments were conducted using two rice cultivars differing in susceptibility to Zn deficiency, and four bicarbonate concentrations (0, 5, 10, 20 mM). Bicarbonate (5–20 mM) strongly inhibited root growth of the Zn-inefficient cultivar within 4 days of treatments. In contrast, root growth of the Zn-efficient cultivar was slightly stimulated with bicarbonate at 5–10 mM and not affected at 20 mM. The inhibitory effect of bicarbonate on root growth in the Zn-inefficient cultivar was mainly that of impairment of new root initiation rather than suppression of elongation of individual roots. Bicarbonate (5–20 mM) increased the concentrations of malate, succinate and citrate in the roots of both cultivars, but to a greater extent for the Zn-inefficient than for the Zn-efficient cultivars. The results suggest that the impairment of root growth was likely to be the initial action of bicarbonate in inducing Zn deficiency in lowland rice, and the inhibitory effect of bicarbonate on root growth of the Zn-inefficient cultivar might result from high accumulation and an insufficient compartmentation of organic acids in the root cells.     

Aluminum accumulation and associated effects on 15NO3 − influx in roots of two soybean genotypes differing in Al tolerance

A study was conducted to examine aluminum (Al) exclusion by roots of two differentially tolerant soybean (Glycine max L. Merr.) lines, Pl-416937 (Al-tolerant) and Essex (Al-sensitive). Following exposure to 80μM Al for up to 2 h, roots were rinsed with a 10 mM potassium citrate solution and rapidly dissected to allow estimation of intracellular Al accumulation in morphologically distinct root regions. Using 10 min exposures to 300μM ¹⁵NO₃ ⁻ and dissection, accompanying effects on NO₃ ⁻ uptake were measured. With Al exposures of 20 min or 2 h, there was greater Al accumulation in all root regions of Essex than in those of Pl-416937. The genotypic difference in Al accumulation was particularly apparent at the root apex, both in the tip and in the adjacent root cap and mucilage. Exposure of roots to Al inhibited the uptake of ¹⁵NO₃ ⁻ to a similar extent in all root regions. The results are consistent with Al exclusion from cells in the root apical region being an important mechanism of Al tolerance.     

Root growth,macro-nutrient uptake dynamics and soil fertility requirements of a high-yielding winter oilseed rape crop

Shoot growth, root growth and macro-nutrient uptake by a high-yielding (5t/ha grain) winter oilseed rape crop have been measured. Maximum rooting density in the top 20cm of soil was 9.4 cm cm⁻³ and roots reached a depth of at least 1.8 m. Maximum nutrient uptakes were 364 kg ha⁻¹ for N, 43 kg ha⁻¹ for P, 308 kg ha⁻¹ for K, 287 kg ha⁻¹ for Ca and 16 kg ha⁻¹ for Mg. A 30-day drought coincided with the flowering period and root and shoot growth, as well as nutrient uptake rates, were reduced. Nutrient concentrations in the soil solution necessary to sustain the nutrient fluxes into the root system by diffusive supply have been calculated. Peak values were in the range 10 μM for P to 87 μM for N, lower than the observed concentrations, and it was concluded that nutrient transport to roots was not a limitation to uptake by this rape crop.     

Combined effects of phytohormone, indole-3-butyric acid, and methyl jasmonate on root growth and ginsenoside production in adventitious root cultures of Panax ginseng C.A. Meyer

Indole-3-butyric acid at 25 μM with methyl jasmonate (MJ) at 100 μM in Panax ginseng synergistically stimulated both root growth and ginsenoside accumulation compared with 100 μM MJ alone. Productivity of ginsenoside was 10 mg l⁻¹ d⁻¹ compared to 7.3 mg l⁻¹ d⁻¹ with MJ elicitation alone.