2018 Volume 87 Issue 4 Pages 541-548
We carried out a comparative study on the effect of mineral fertilizers and biofertilizers on the nutrient concentration of Laelia anceps Lindl. subsp. anceps (Orchidaceae) seedlings. The first nutrient solution (Min-Fert) was prepared with commercial mineral fertilizers (Peters Professional® 30N-10P-10K); the second one (Biofert) from Nutro® commercial biofertilizer; and the third with a combination of mineral sources and biofertilizers (Min-Fert + Biofert). Mineral fertilization promoted significant differences in N concentration in leaves and roots. Also, it increased K and the concentration of some micronutrients in the roots. The phosphorous concentration increased in pseudobulbs and roots with the Min-Fert and Min-Fert + Biofert. Biofertilization increased the N concentration in pseudobulbs, and Min-Fert + Biofert increased the Ca and Mg concentration in the roots, as well as the concentration of Fe and Cu in pseudobulbs and Cu in the leaves. Interestingly, Min-Fert significantly increased the nutrient concentration in the roots in comparison to the other tissues. We demonstrated that the use of biofertilizers in L. anceps subsp. anceps (alone or as a supplement to mineral fertilization), represents an alternative to reduce production costs and mitigate the negative impacts of mineral fertilization on the environment.
One of the fundamental factors for mass production of orchids is a knowledge of their specific nutritional characteristics, but a lot of work is needed in terms of tissue analysis, N:P:K ratio and the nutritional requirements in different growth states (Hew and Yong, 2004) to develop specific fertilization programs.
The management requirements of many wild orchids are unknown as the main nutrition studies on orchids have focused on hybrids, addressing growth analysis, flowering, and nutrient concentration in response to mineral fertilization (Bichsel et al., 2008; Wang, 1996; Wang and Konow, 2002). However, there is very little research on the use of biofertilizers in orchid production. Rather, research has focused on so-called organic fertilizers, which mainly involve the use of manure, ground animal bones mixed with household waste, ash, and other organic components (Hew and Yong, 2004; Naik et al., 2009; Rodrigues et al., 2010a).
A biofertilizer is defined as a preparation containing live or latent cells of N-fixing strains or phosphate solubilizers, which help plants to increase N fixation or improve the availability of nutrients in the soil so they can be easily assimilated by plants (Boraste et al., 2009). Microorganisms that can be used as biofertilizers include bacteria, fungi, and blue-green algae. An important group of microorganisms included in this type of biofertilization are called plant growth promoting rhizobacteria (PGPR) (Vessey, 2003), such as those of the genus Bacillus, Pseudomonas, Azospirillum, Rhizobium, and Erwinia, among others (Kloepper et al., 2004; Rodríguez and Fraga, 1999; Shen, 1997). Biofertilizers have emerged as an important component of integrated nutrient supply systems for improving crop yield (Wu et al., 2005). The use of biofertilizers has recently spread to ornamental crops (El-Khateeb et al., 2010; Habib and Zaghloul, 2012), but in orchids it is virtually nonexistent.
Like other plants, orchids need several essential elements (macro and micronutrients) for normal growth, but they take longer to show mineral deficiencies, and the mineral concentration of an orchid tissue may depend on the growth medium, genus, age, and fertilization program (Hew and Yong, 2004). According to Poole and Sheehan (1982), Laeliocattleya Aconcagua and Laeliocattleya culminant display different patterns of nutrient concentrations, based on the organs of the plants. Moreover, the nutrient concentration of Laelia purpurata ‘werkhanserii’ × L. lobata ‘Jeni’ seedlings varies depending on the type of organic and mineral fertilization (Rodrigues et al., 2010a). Importantly, the concentration of the fertilizer and the composition of the growth medium affect Laelia anceps growth, causing an imbalance in the concentration of nutrients in the stem (structure formed by leaf and pseudobulb) (Jiménez-Peña et al., 2013).
Laelia anceps is the most common species used for hybridization due to the beauty of its flowers and easy cultivation (Soto-Arenas, 1993). Thus, the hybrids Laurie (L. anceps × Rsc. [Blc.] Beauty R. van Rooyen) (Sander’s List, 2007), Laelia Godmero (L. [Schom.] marginata [crispa] × L. [Schom.] undulata), Laeliocattleya Henrique Romero Graf (L. [Schom.] lyonsii × C. amethystoglossa) (Royal Horticultural Society, 2016), have been bred using L. anceps as a parent. This species distributes from Mexico to Honduras, though in Mexico, current populations are decreasing (Soto-Arenas, 1993), and some of the species of Laelia genus have been reported as already extinct in the wild according to the Mexican Official Standard NOM-O59 SEMARNAT 2010 (http://dof.gob.mx/nota_detalle.php?codigo=5173091&fecha=30/12/2010). Therefore, it is necessary to promote the production of this species in horticultural systems, and thus reduce its risk of extinction from its natural ecosystems in tropical forests. In addition, such systems must be sustainable and foster the use of environmentally friendly technologies.
The aim of this research was to assess the effect of mineral fertilizers and biofertilizers on the nutrient concentration in the leaves, pseudobulbs, and roots of Laelia anceps subsp. anceps seedlings.
Young, 5–8 cm tall seedlings of L. anceps subsp. anceps were established in a greenhouse, where they remained in adaptation for eight weeks, with diurnal (from 7–18 h) temperature and relative humidity averages of 23°C and 42%, respectively, and night (from 18–7 h) averages of 12°C and 71%. Average light intensity was 90 μmol·m−2·s−1. After the adaptation phase, the plants were transplanted into 160-mL translucent pots with a substrate consisting of pine bark (Ecorteza®; PISUMA S. A. de C. V., Tlalpan, Mexico) and perlite at a ratio of 75:25 (v:v), with particle sizes from 4 to 6 and 2 to 3 mm, respectively. The material was steam-sterilized at 120°C for 1 h.
Nutrient solutionsSeedlings were irrigated for 10 months with nutrient solutions prepared using mineral fertilizers (Min-Fert) and biofertilizers (Biofert). The components of the solutions were applied either separately or combined (Min-Fert + Biofert), with similar nutrient concentrations (Table 1). As a control (C) seedlings were irrigated with tap water. Treatments were distributed in a completely randomized experiment with 20 replications.
Nutrient concentration (mg·L−1) in the different fertilization sources, for the growth of Laelia anceps subsp. anceps.
The Peters Professional® 30-10-10 (The Scotts Company LLC, Marysville, OH, USA) fertilizer was used as a source of N-P-K. In addition, this fertilizer contains CaSO4 2H2O, MgSO4 7H2O, FeSO4 7H2O, CuSO4 5H2O, ZnSO4 7H2O, and H3BO3. Nutro N, Nutro P, Nutro K, and Nutro Ca, which contain Azospirillum brasilensis and Bacillus subtilis (Rodríguez and Fraga, 1999; Zehnder et al., 2001), were used as biofertilizers. In addition, the biofertilizer included humic acids, auxins, and Glomus intraradices (an arbuscular mycorrhizal fungi), as well as amino acids (which improve nutritional quality and enhance plant growth) (Khade and Rodrigues, 2009; Senn and Kingman, 1973; Shen, 1997) (Table 2). An organic certified product, Carboxy®Micro (Innovak Global, Chihuahua, Mexico), was used as a source of micronutrients applied together with biofertilization.
Additional macronutrients and microorganisms included in Nutro® biofertilizers.
The pH of the nutrient solution was 5.5. Treatment application began two weeks after transplant. Plants were supplied with 30 mL of the nutrient solution every week. Additionally, they were watered with tap water every day, except the day when the nutrient solution was applied.
Nutrient analysis in plant tissuesFor the nutrient analysis of plant tissues, dry biomass samples were taken from the leaves, pseudobulbs, and roots. Once dried, they were grounded in a Wiley-brand stainless steel mill. Total nitrogen concentration was determined by the semi-micro Kjeldahl method (Bremner, 1965) using salicylic-sulfuric acid for digestion. Determination of P, K, Ca, Mg, Fe, Cu, Zn, Mn, and B concentrations was carried out by wet digestion of the dry matter with a mixture of perchloric and nitric acids (Alcántar and Sandoval, 1999). The reading of the extracts obtained after digestion and filtration was made using an inductively coupled plasma atomic emission spectrometer (725 ICP-OES; Agilent, Santa Clara, CA, USA).
Data analysisData were analyzed by ANOVA using the SAS Statistical Analysis System package (SAS, 2011), and a means comparison was carried out using the Tukey’s, test (α = 0.05).
A differential pattern of nutrient concentration was observed among plant organs analyzed, due to the fertilizers used (Figs. 1–4). Nitrogen concentrations in the roots (25.4 g·kg−1) and leaves (15.3 g·kg−1) showed a significant increase with mineral fertilization (Min-Fert, P = 0.0001 and 0.0001), in relation to the rest of the treatments and the control. Mineral fertilization, with 24.8% of urea, 2.1% of ammonium, and 3.1% of nitrate improved the N concentration in the roots (25 g·kg−1), possibly due to the function of the velamen in orchids roots related to the absorption of mineral ions. According to Trépanier et al. (2009), because of the special nature of velamen, Phalaenopsis roots can uptake large amounts of N directly as urea in vitro, suggesting that urea can be used in nutrient solutions for the growth of potted Phalaenopsis and other orchids. Indeed, urea can be directly absorbed by the roots of Laelia purpurata (Marques da Silva et al., 2013), while velamen plays a crucial role in nutrient uptake by epiphytic plants (Zotz and Winkler, 2013). After fertilization, L. anceps roots are prone to darkening and dehydrating. Therefore, one day after the application of the nutrient solution, plants need to be watered in order to reduce the risk of accumulation of salts and thus avoid root damage.
Concentration of N in different organs of Laelia anceps subsp. anceps. Min-Fert: mineral fertilization; Biofert: biofertilization; Min-Fert + Biofert: mineral fertilization complemented with biofertilization. Mean values with different letters + SD indicate significant differences according to Tukey’s test at the P ≤ 0.05 level.
Concentration of P in different organs of Laelia anceps subsp. anceps. Min-Fert: mineral fertilization; Biofert: biofertilization; Min-Fert + Biofert: mineral fertilization complemented with biofertilization. Mean values with different letters + SD indicate significant differences according to Tukey’s test at the P ≤ 0.05 level.
Concentration of K in different organs of Laelia anceps subsp. anceps. Min-Fert: mineral fertilization; Biofert: biofertilization; Min-Fert + Biofert: mineral fertilization complemented with biofertilization. Mean values with different letters + SD indicate significant differences according to Tukey’s test at the P ≤ 0.05 level.
Concentration of Ca and Mg in different organs of Laelia anceps subsp. anceps. Min-Fert: mineral fertilization; Biofert: biofertilization; Min-Fert + Biofert: mineral fertilization complemented with biofertilization. Mean values with different letters + SD indicate significant differences according to Tukey’s test at the P ≤ 0.05 level.
Plants are able to absorb and assimilate different forms of N, including nitrate (NO3−), ammonium (NH4+), urea [CO(NH2)2], and even some amino acids (Nacry et al., 2013). Furthermore, plants may discriminate among N forms, even when they are applied in equal doses (Song et al., 2016).
According to Yu et al. (2002), N from free and combined amino compounds represents from 59 to 78% of the dissolved organic N. Furthermore, the amino acid production can be enhanced by high microbial amino acid demand and there is an inverse relationship between N concentration and proteolytic activity (Weintraub and Schimel, 2005). In addition, the role of amino acid uptake systems in roots is simply to recover amino acids released from the root cells (Näsholm et al., 2009). These facts can explain, at least in part, the results we observed for N concentrations in leaves and roots. Importantly, the number and functions of amino acid transporters mediating root amino acid uptake, the process of uptake, the interaction between amino acids in the uptake process, to what extent different compounds compete for uptake, and to what extent their uptake is complementary are not yet fully understood (Näsholm et al., 2009).
Even though the treatment with mineral fertilization concentrated the greatest amount of N in leaves, the concentration was low compared to other studies, which may be due to the characteristics of the species, age of the plant, and agronomic conditions. Furthermore, this response can be attributed to the specific anatomy of L. anceps subsp. anceps leaves (succulent, coriaceous, and rigid) (Halbinger and Soto-Arenas, 1997). Hietz et al. (1999) analyzed N concentrations of different epiphytic plants, and found that succulent orchids had lower foliar N concentrations compared to thin leaves orchids. Based on this idea, our results were consistent with those reported by Wang and Konow (2002), who used 200 mg·L−1 of N in different fertilizer formulations to analyze the mineral concentration of Phalaenopsis Atien Kaala and found different concentrations of N in the foliage, where fertilizers containing urea had lower N concentrations in the leaves. This in turn may be associated with the rate of mineral assimilation of orchids, which is usually slow compared to other higher plants (Hew et al., 1993).
Biofert significantly increased the N concentration (12.8 g·kg−1, P = 0.0045) in pseudobulbs compared to the rest of fertilization treatments (Fig. 1). Orchid pseudobulbs play a crucial role as a storage organ of mineral nutrients (Ng and Hew, 2000); additionally, pseudobulbs are capable of absorbing nutrients. For instance, plants of the myrmecophytic orchid Caularthron bilamellatum absorbed all tested inorganic and organic nitrogen forms through the inner surface of the pseudobulbs. Ammonium (NH4+) and glutamine absorption followed Michaelis–Menten kinetics, while the uptake rates of urea and glutamine were not significantly different (Gegenbauer et al., 2012). The assimilation sites differ between N forms, and amino acids are preferentially metabolized in the roots. Absorbed N derived from amino acids is allocated to shoots at a slower rate than nitrate (NO3−). It is well known that the short-term fates of absorbed NH4+ and NO3− differ, while little is known regarding the metabolism and distribution of the N derived from amino acids following uptake or regulation of these processes in response to plant nitrogen status. Due to the central and multiple roles of many amino acids, regulation of their metabolism can be expected to occur at multiple levels and in response to many factors (Persson et al., 2006). Because of the age of the plants evaluated in our experimental conditions (2-years old), pseudobulbs concentrated N for future growth and the reproductive phase. According to Ng and Hew (2000), the removal of nutrients stored in older pseudobulbs together with the high nutrient absorption rates suggests a nutrient demand aimed at the development of new pseudobulbs. In Spathoglottis unguiculata, a high percentage of assimilated 14C was exported from the pseudobulb to other tissues, while it accumulated a higher percentage of assimilated 14C (44%) during the vegetative stage than during the flowering stage (21–30%) (Hew et al., 1998).
Phosphorous concentrations were statistically higher with Min-Fert and with the Min-Fert + Biofert in pseudobulbs (1.7 and 1.5 g·kg−1, P = 0.0001) and roots (1.4 and 1.4 g·kg−1, P = 0.0002). In addition, the highest P concentration in leaves was observed in Min-Fert + Biofert in comparison to the control (P = 0.0500). Nevertheless, this treatment (Min-Fert + Biofert) was statistically similar to Min-Fert and Biofert (Fig. 2). Accordingly, Rodrigues et al. (2010a) reported that domestic organic fertilization plus the addition of Peters Professional® fertilizers increased the P concentration.
We observed that biofertilization increased the P concentration per se. However, together with mineral fertilization, the P concentration was enhanced (Fig. 2). The phosphate-solubilizing bacteria in biofertilizers can explain the increase in phosphorus availability (Vessey, 2003), and combined with Peters Profesional® fertilizer, it increased the uptake and concentration of this nutrient in pseudobulbs and roots. Phosphate-solubilizing microorganisms release organic and inorganic compounds as a primary mechanism of P solubilization. In addition to organic acids, they produce chelating and humic substances, siderophores, and proton extrusion mechanisms, which have a key role in P solubilization (Rathi and Gaur, 2016). Accordingly, Hashemabadi et al. (2012), reported the highest P concentration in stems of Tagetes erecta L. was found in plants treated with phosphate biofertilizer (Barvar-2) combined with 400 mg·L−1 of chemical phosphate. They showed that seeds and transplanted roots inoculated with the biofertilizer achieved the highest P uptake, which may be related to the increased availability of P and the capacity improvement of uptake plants. Barvar-2 contains phosphate-solubizing microorganisms such as Bacillus lentus and Pseudomonas putida. It is proposed that these phosphorus biofertilizers can replace traditional P fertilizers as they have the ability to dissolve calcium phosphate and apatite associated with plant roots (Mohammadi et al., 2012).
From the highest to the lowest average value, the order of K concentration among organs was: leaves (i.e. 11.36 g·kg−1) > pseudobulb (i.e. 4.14 g·kg−1) > roots (i.e. 3.42 g·kg−1), regardless of the fertilization treatment applied. The mineral fertilization significantly increased the K concentration in the roots (P = 0.0007) (Fig. 3). Probably, the young age of the plants under study did not reflect nutrient deficiency. In Phalaenopsis, symptoms of K deficiency became evident when plants reached the reproductive stage (Wang, 2007). With 50 or 100 mg·L−1 of K, plants showed an apparent healthy vegetative stage, but later on, they showed some degree of leaf yellowing or abscission during flowering (Wang, 2007). Bichsel et al. (2008) recommend 100 mg·L−1 of K for optimal vegetative growth and reproductive development of Dendrobium Red Emperor ʻPrinceʼ. In our case, the concentration of K in nutrient solutions was 75 mg·L−1 (Table 1). Potassium has a crucial role in the energy status of plants, affects the process of photosynthesis and is involved in the synthesis, translocation, and storage of assimilates (Alemán et al., 2011). According to Yong and Hew (1995), Oncidium ʻGoldianaʼ has a highly integrated source-demand assimilate partition pathway; while the higher leaves supplied the pseudobulb, the lower leaves supplied the roots. These responses could explain the highest concentration of K in the leaves in our research.
Contrary to the results obtained in P concentrations, no positive effects of Biofert alone or in combination with Min-Fert on the K concentration of all evaluated organs were observed (Fig. 3). According to Etesami et al. (2017) the effect of PGPR on K availability and the interactions between PGPR and potassium-solubilizing bacteria (KSB) must be addressed in future studies.
Biofertilization and Min-Fert + Biofert increased the Ca concentration in roots (3.3 and 3.7 g·kg−1, P = 0.0003) (Fig. 4). Unlike N and P, the mineral fertilization significantly decreased the concentration of Ca (P = 0.0003) and Mg (P = 0.0001) in the roots (Fig. 4). The Ca concentration was not statistically different in leaves and pseudobulbs. The highest concentration of Mg in the roots of control plants could be due to the concentration of this nutrient in tap water (29 mg·L−1) (Table 1) compared to that of mineral fertilization.
Mineral fertilization promoted a reduction in the foliar concentration of Ca compared to the biofertilization, though no significant differences were observed among treatments (Fig. 4). Calcium-soluble fertilizers are recommended to improve the growth of orchids and the quality of their blooms. Actually, the Peters Professional® fertilizer has Ca and S deficiencies. Despite the complementary amounts of Ca in nutrient solutions, it is necessary to supplement the nutritional solutions with higher doses of this nutrient for greater growth in later stages and reproductive development of L. anceps subsp. anceps. Rodrigues et al. (2010b) reported a higher dry matter yield, number, and weight of leaves of Epidendrum ibaguense with different amounts of lime. Hsu et al. (2010) reported that supplementation with calcium nitrate (300 mg·L−1) improved the quality of the inflorescences of Oncidium ʻGower Ramseyʼ. Likewise, Naik et al. (2013) reported that the addition of 300 mg·L−1 of Ca improved the growth of Cymbidium ʻMint Ice Glacierʼ.
The Mg concentrations showed little variation in the three analyzed organs (between 4 and 5 g·kg−1), (Fig. 4). Due to their young age, L. anceps plants may not have shown Mg deficiencies because this is observed in older leaves, which tend to translocate Mg to newer leaves (Batchelor, 1981).
Micronutrients display different concentration patterns in plant tissues in response to mineral fertilizers and biofertilizersWith the exception of B and Mn, the highest concentrations of micronutrients were observed in the roots, regardless of treatment (Table 3). The roots are the main site where mineral nutrient uptake takes place, and the mobilization of such nutrients from the roots to other tissues may depend on the nature of the mineral element. For instance, only a small amount of heavy metals reach the shoots and they stay mainly in the roots, since heavy metals show a low solubility at the root surface and in the root apoplast, or to compartmentation in cells avoiding release to the xylem (Page and Feller, 2015).
Concentration of micronutrients (mg·kg−1) in different organs of Laelia anceps subsp. anceps.
The iron concentration was statistically higher in the pseudobulbs with Biofert and with the combination of Min-fert + Biofert (P = 0.0001), while in the roots the concentration of this micronutrient was higher with Min-Fert in comparison to Biofert (P = 0.0065), as shown in Table 3.
The concentration of Cu in leaves and pseudobulbs was higher (P = 0.0039 and P = 0.0008) with Biofert in comparison to the control. In the roots, the Cu concentration was higher with Min-Fert + Biofert (P = 0.0023) in comparison to Biofert and Min-Fert alone, but it was not statistically different to the control (Table 3).
The zinc concentration was significantly higher in the roots with Min-Fert (P = 0.0011), and in pseudobulbs with Min-Fert and Min-Fert + Biofert (P = 0.0105) in comparison to the control. Nevertheless, treatments had no effect on Zn foliar concentrations (Table 3).
The manganese concentrations in leaves were not different among treatments, but in both the pseudobulbs and roots, the concentration of this element was significantly increased (P = 0.0001 and 0.0001) when plants were treated with Min-Fert + Biofert compared to the rest of the treatments (Table 3).
The boron concentration in pseudobulbs was significantly reduced (P = 0.0207) with Min-Fert + Biofert, in comparison to the control. In fact, B concentration was higher in the pseudobulbs of control plants, in relation to Min-Fert + Biofert. Rodrigues et al. (2010a) reported B toxicity with different combinations of commercial organic fertilizer (average 319 mg·kg−1) which differs from our results (average 67.7 mg·kg−1).
Biofertilization alone or in combination with mineral fertilization increased the concentration of Fe in pseudobulbs, in comparison to Min-Fert and the control. On the other hand, Biofert alone raised the concentrations of Cu in leaves and pseudobulbs, which was statistically similar to levels observed in plants treated with Min-Fert + Biofert, but higher than the control in the same organs. Interestingly, the combination of Min-Fert + Biofert increased the concentration of Mn in pseudobulbs and roots, and this mean was statistically higher than those observed in the other treatments, including the control, in these organs (Table 3). These results are consistent with those observed for the N concentration in pseudobulbs and for P concentrations in all evaluated organs (Figs. 1 and 2). According to Rana et al. (2011), PGPR enhanced the uptake of N, P, and micronutrients in treated plants, which can partially explain our results.
Comparison of mineral fertilization vs biofertilizationConcerning the analysis of macronutrient concentrations, mineral fertilization increased the concentration of N in leaves and roots (Fig. 1). The combination of Min-Fert + Biofert increased the P concentration in pseudobulbs and roots (Fig. 2). Additionally, Min-Fert increased K and Zn concentration in roots (Fig. 3; Table 3). The highest K and Ca concentrations were found in leaves regardless of the nutrient solutions tested, in comparison to the rest of organs, with average values of 11.3 and 9.7 g·kg−1, respectively (Figs. 3 and 4).
The biofertilization increased the N concentration in pseudobulbs (Fig. 1), and in combination with the mineral fertilization, this treatment increased the Ca concentration in the roots (Fig. 4), as well as the concentration of Fe in pseudobulbs (Table 3).
The nutrient concentration in the roots by the action of the mineral fertilization was very high, which suggests that the concentrations in the nutrient solution should be lower because of the possible slow uptake and transport rates of nutrients by plants. Indeed, excessive application of fertilizers may potentially damage the roots.
It is possible that interactions between the biofertilizer components could increase some nutrient concentrations. For instance, humic acids significantly increased macro- and micronutrients concentrations of leaves and scapes in gerbera (Gerbera jamesonii L.) ‘Malibu’, while high levels of humic acids reduced the concentrations of Fe and Zn (Nikbakht et al., 2008). Karakurt and Aslantas (2010) found that the B. subtilis OSU-142 strain increased the Mg and Fe concentration in apple leaves. In the present study, it was observed that biofertilization increased leaf Mg concentrations in pseudobulbs, while Biofert and Min-Fert + Biofert significantly increased Fe concentration in pseudobulbs, where the presence of B. subtilis could act as a biostimulant enhancing the nutrient status of the plant.
Chang et al. (2008) developed a patent called “Disclosed”, which consists of a biofertilizer containing a mixture of symbiotic microorganisms (Rhizoctonia sp.) and growth substances, in order to promote the growth of orchids, increase the flowering rate and improve their quality, while reducing diseases in roots and thereby decreasing the use of pesticides. Tejeda-Sartorius et al. (2013) evaluated growth and dry matter accumulation of L. anceps subsp. anceps with the same biofertilizer used in the current research, and obtained higher values in relation to these with mineral fertilization.
Our results show the possibility of using biofertilizers in L. anceps subsp. anceps, mainly as a supplement to mineral fertilization. Nevertheless, a greater range of application doses must be tested, which could potentially reduce the quantity of mineral fertilizer applied in the cultivation of orchids.
ConclusionsAccording to our findings, the use of biofertilizers in combination with mineral fertilizers is recommended in order to increase the availability and uptake of some nutrients in young Laelia anceps subsp. anceps plants. The use of biofertilizers could reduce the consumption of mineral fertilizers and be a sustainable tool to produce orchids under controlled conditions. In future studies, it will be necessary to carefully investigate the processes of uptake, transport and allocation of nutrients from biofertilizers in Laelia anceps.
