SPAD Index Research Articles

Cucumber seedlings production: tray size impact on development

The size of the tray in seedling production has a direct influence on the area of ​​root development and availability of resources, such as water as well as nutrients, with a potential impact on the seedling final quality. The objective of this work was to analyse the impact of the tray size on the development of cucumber seedlings. As such, this study was developed in two experiments: in the first, seedlings produced in trays with 50 and 128 cells were compared, while in the second, trays with 50, 98, and 128 cells were considered. For that, polyethylene trays and commercial substrate were used. The trays were kept in a greenhouse, and evaluations were carried out at 21 days after sowing. Morphological development and SPAD index were analysed. The data were submitted to ANOVA and the means compared by the Tukey test (0.05). Linear correlation was performed between the analysed variables. The best development of cucumber seedlings was obtained by adopting trays with 50 cells. Cucumber seedlings produced in trays with a higher number of cells show reduced development, mass accumulation and lower photosynthetic activity.

Correlation between SPAD and chlorophylls a, b and total in leaves from Vaccinium corymbosum L. cv. Biloxi, Legacy and Victoria in the high tropics

Blueberries in the Ericaceae family are important, cultivable species for commercial and industrial purposes. Critical parameters for evaluating the nutritional and physiological status of plants include estimates of photosynthetic pigments such as chlorophylls; however, this is a destructive, expensive and time-consuming method that is not easily accessible for agricultural producers. For this reason, in recent years, several technological solutions have been made available, such as the SPAD-502 chlorophyll index meter, which has demonstrated efficiency in terms of rapid estimates of total chlorophyll content in the field. Therefore, the objective of this research was to evaluate the contents of chlorophylls a, b and total obtained with spectrophotometry and to determine the correlation with the non-destructive method (SPAD) in blueberry plant (Vaccinium corymbosum L.) cultivares Biloxi, Legacy and Victoria, in the vegetative phase under conditions of the municipality of Paipa-Boyaca (Colombia). The data obtained with the SPAD-502 ranged from 57.4 to 62.8 SPAD in the 'Victoria', 61.2 to 68.3 in the 'Biloxi', and 68.2 to 73.1 in the 'Legacy'. The content of chlorophylls a, b and total presented a positive and significant correlation with the SPAD index, with a correlation coefficient (r) greater than 0.91 and adjustment to simple linear regression models with a coefficient of determination (R2) greater than 0.90 in the three cultivars. This confirms the usefulness and importance of using SPAD for non-destructive estimation of chlorophyll content under field conditions.

Pocket-sized sensor for controlled, quantitative and instantaneous color acquisition of plant leaves

The color of plant leaves can be assessed qualitatively by color charts or after processing of digital images. This pilot study employed a novel pocket-sized sensor to obtain the color of plant leaves. In order to assess its performance, a color-dependent parameter (SPAD index) was used as the dependent variable, since there is a strong correlation between SPAD index and greenness of plant leaves. A total of 1,872 fresh and intact leaves from 13 crops were analyzed using a SPAD-502 meter and scanned using the Nix™ Pro color sensor. The color was assessed via RGB and CIELab systems. The full dataset was divided into calibration (70% of data) and validation (30% of data). For each crop and color pattern, multiple linear regression (MLR) analysis and multivariate modeling [least absolute shrinkage and selection operator (LASSO), and elastic net (ENET) regression] were employed and compared. The obtained MLR equations and multivariate models were then tested using the validation dataset based on r, R2, root mean squared error (RMSE), and mean absolute error (MAE). In both RGB and CIELab color systems, the Nix™ Pro color sensor was able to differentiate crops, and the SPAD indices were successfully predicted, mainly for mango, quinoa, peach, pear, and rice crops. Validation results indicated that ENET performed best in most crops (e.g., coffee, corn, mango, pear, rice, and soy) and very close to MLR in bean, grape, peach, and quinoa. The correlation between SPAD and greenness is crop-dependent. Overall, the Nix™ Pro color sensor was a fast, sensible and an easy way to obtain leaf color directly in the field, constituting a reliable alternative to digital camera imagery and associated image processing.

Quality Index of Passion Fruit Seedlings by Using Physically Parameters

Passion fruit (Passiflora edulis) has aroused interest from producers, leading to an intense demand for technical information, especially for obtaining quality seedlings. The objective of this study was to evaluate passion fruit seedlings according to age and morphological characteristics. The experiment was carried out at the seedling nursery of the State University of Montes Claros, Campus Janaúba-MG, Brazil, from March to June 2017. The cultivars BRS Gigante Amarelo, BRS Rubi do Cerrado, BRS Pérola do Cerrado and Redondo Amarelo were evaluated, distributed in randomized blocks with five replications, in a split-plot scheme (4 × 4). There was an adjustment of the model (IQM = 6.3857 − 0.3892 NL + 3.3512 SD − 0.2063 SPAD + 0.0730 LA), which proposes a quality parameter of passion fruit seedlings, high level of significance and coefficient of determination, necessary for the reliability and accuracy of the results obtained. Considering the proposed model (IQM), there is no need for destructive analysis, and evaluations can be performed in the nursery itself as soon as a seedling lot reaches the recommended height of 30 cm. The evaluated characteristics contribute significantly to the quality of the seedling, and it is recommended, besides the height measurement, to evaluate the number of leaves, the stem diameter, the leaf area and the SPAD index, because the combination of these parameters will guarantee the necessary quality of the seedlings to be transplanted in the field.

Ferrum sulphuricum CONTROLLING POWDERY MILDEW ON TOMATO GENOTYPES

ABSTRACT Powdery mildew is an important disease in tomato, which requires technologies for its control. Homeopathy is a science that has been improved as an alternative method in agriculture. Thus, this study aimed to evaluate the homeopathic medicine Ferrum sulphuricum in 6, 12, 24, 48, 72 and 96CH dynamizations on powdery mildew control. The experiment was conducted from May to June 2013 in a greenhouse, in split-split- plot design, and the results were compared with the controls 30% ethanol and distilled water. We evaluated the area under disease progress curve (AUDPC), relative chlorophyll index (SPAD), influence on plant growth by volume and mass of roots, and mass of fruits and shoots and even the pathogen sporulation on leaves. For the AUDPC, all the dynamizations reduced the disease. The Santa Clara genotype showed up to 41% less and Cedro 31% less disease compared with the control ethanol, in the upper third of the plant. For the SPAD index, there was an increase of up to 322% in the middle third of the plant treated with 24CH dynamization. For the growth variables, all the dynamizations increased up to 197% the volume and weight of roots for Cedro and Santa Clara. The 6, 12, 24, 72 and 96CH dynamizations reduced the pathogen sporulation on Santa Clara tomato leaves by up to 40%. The data indicate that the medicine Ferrum sulphuricum can control powdery mildew on tomato, increase the growth of plants and that there is a differential response according to the host genotype.

Apple leaf macro- and micronutrient content as affected by soil treatments with fertilizers and microorganisms

The effects of bacterial and fungal inocula on the nutritional status of ‘Sampion’ apple trees was evaluated in three-years study (2018–2020). The experiment was set up in a two-factor system: (i) fertilization (without fertilization or mineral fertilization with nitrogen, phosphorus, potassium); (ii) application of beneficial microorganisms (without application, application of fungi or bacteria). The mixture of beneficial soil fungi contained two species: Aspergillus niger and Purpureocillium lilacinum. The mixture of beneficial bacteria contained three strains of Bacillus (Bacillus sp., Bacillus amyloliquefaciens and Paenibacillus polymyxa). The analysis of mineral content and leaf greenness (SPAD index) was performed on the samples collected from the trees in August. The lack of mineral fertilization caused a significant decrease in the nitrogen content of apple leaves, which resulted in their lighter color (lower SPAD index). The application of filamentous fungi or bacterial strains had a modifying effect on the mineral composition of apple leaves, what became evident especially in the third year of the study. An increase in the concentration of nitrogen, calcium, magnesium, sulphur and most microelements (except for boron) was found as a result of the influence of tree mineral fertilization and microorganisms applied to the soil. In the absence of mineral fertilization of the trees, the applied microbial inocula resulted in the significant increase of concentration of most macro- and microelements in the leaf tissue (except for magnesium and boron).

Salt Tolerant Eggplant Rootstocks Modulate Sodium Partitioning in Tomato Scion and Improve Performance under Saline Conditions

Grafting on salt tolerant eggplant rootstocks can be a promising approach for enhancing the salinity tolerance of tomato. In this study, the performance of tomato cv. Kashi Aman grafted on two salt tolerant eggplant rootstocks (IC-111056 and IC-354557) was evaluated against non-grafted control under saline (ECiw 6 and 9 dS m−1) and non-saline (ECiw ~1 dS m−1) irrigation for 2 years. Grafting improved tomato plant performance under salt stress. Moreover, rootstock IC-111056 outperformed IC-354557. An increase in the average fruit yield of grafted plants compared with non-grafted control at 6 and 9 dS m−1 was 24.41% and 55.84%, respectively with rootstock IC-111056 and 20.25% and 49.08%, respectively with IC-354557. Grafted plants maintained a superior water status under saline irrigation, evidenced with the relative water content and chlorophyll SPAD index, along with higher proline and antioxidant enzyme activities (superoxide dismutase, catalase, and ascorbate peroxidase). Rootstocks mediated the partitioning of toxic saline ions in the scions by promoting higher Na+ accumulation (14% of mean accumulation) in the older leaves and lower (24%) in the younger leaves of grafted plants. This resulted in higher K+/Na+ ratios within the younger (active) leaves of the grafted plants. Our study demonstrates that grafting tomato seedlings on selected salt tolerant eggplant rootstocks is a viable alternative for improving plant physiological status and fruit yield under salt stress, through favorable modulation of salt ion partitioning in the scions.

Parâmetros fisiológicos em plantas de tomate submetidas à salinidade e tratadas com brassinosteroide

Abstract The objective of this work was to evaluate the effects of brassinosteroid on chlorophyll a fluorescence parameters, the SPAD index, and leaf succulence in young tomato (Lycopersicon esculentum) plants under salt stress. The experimental design was a randomized complete block, in a 5×2 factorial arrangement - five levels of water salinity (0.5, 1.5, 3.0, 4.5, and 6.0 dS m-1) × two rates of 24-epibrassinolide (0 and 10-6 mol L-1 EBL). At 23 days, the treatment without EBL showed that the increase of water salinity reduced the maximum, primary, and effective photochemical efficiency of PSII, as well as the electron transport rate, the SPAD index, leaf succulence, total dry mass, and the stress tolerance index, but increased initial fluorescence and relative excess energy in PSII. With the increase of water salinity, in the EBL treatments, there was an increase in the effective photochemical efficiency of PSII, the electron transport rate, the SPAD index, leaf succulence, total dry mass, and the stress tolerance index. EBL promotes beneficial effects on PSII integrity, the chlorophyll index, and leaf succulence in young tomato plants subjected to salinity levels of up to 6.0 dS m-1 .

Genotypic differences in response of durum wheat (Triticum durum Desf.) to lime-induced iron chlorosis.

Wheat, durum wheat, is the first cereal cultivated and consumed in Tunisia. Because the dominance of calcareous soils in its agroecological systems, known by their low availability of iron (Fe) inducing Fe chlorosis and limiting crop production, its yield remains low. Therefore, the search for tolerant genotypes is always current. In this context, the physiological behavior of six Tunisian genotypes of durum wheat (salim, karim, razek, khiar, inrat100, and maali) cultivated on calcareous and fertile soils for 2 months in a pot experiment was investigated. A greenhouse was used to conduct experiments under natural light. Plant growth, SPAD index, Fe nutrition, Fe distribution, and photosynthesis were monitored and used to evaluate and discriminate their respective physiological responses. On calcareous soil, results revealed reduced plant growth, active Fe, SPAD index, and net photosynthesis. Genotypic differences in the response of wheat to calcareous‐induced Fe deficiency were observed and allowed to classify the genotypes Salim and Karim as relatively tolerant. These genotypes expressed Fe translocation capacity (FeT) up to 3 times, Fe use efficiency for photosynthesis (FeUEAn) up to 1.6 times, and chlorophyll use efficiency for photosynthesis (ChlUEAn) up to 3.5 times greater than that expressed by the other genotypes, particularly inrat100 and maali. Thus, the relative tolerance of Salim and Karim is the result of the high ability of Fe uptake and translocation to shoots to support chlorophyll biosynthesis, photosynthesis, and plant growth as well as an important Fe and chlorophyll use efficiency.

Proline and antioxidant enzymes protect Tabebuia aurea (Bignoniaceae) from transitory water deficiency

Abstract Water deficiency is a major abiotic stress that limits biomass production and drives plant species distributions. We evaluate the effects of water deficiency on ecophysiological and biochemical parameters of seedlings of Tabebuia aurea. Plants were subjected to daily watering (control) and to stress by soil water deficiency for 29 days. Leaf area, plant biomass, gas exchange, SPAD index, maximum quantum yield (Fv / Fm), quantum yield of PSII (ΦPSII), superoxide dismutase (SOD) and L-ascorbate peroxidase (APX) activity, lipid peroxidation, and proline content were recorded. Plants responded to water deficit by reducing leaf area and accumulating proline. Stomatal conductance was reduced to limit the water loss by transpiration. However, limiting CO2 uptake caused reduction in photosynthesis and biomass. The excess of energy unutilized by photosynthesis reduced SPAD index and ΦPSII. As a result, we observed an increase in SOD and APX activity, protecting chloroplast membranes from further damages caused by lipid peroxidation. Our results indicate that T. aurea have capacity to survive under water deficiency reducing stomatal aperture, but affecting the rate of CO2 assimilation. Nevertheless, plants showed mechanisms to preventing damages to the photosynthetic apparatus. Such plasticity is an important adaptation for plants growing in dry environmental.

Evaluating the Growth-promoting Effects of Microbial Biostimulants on Greenhouse Floriculture Crops

Microbial biostimulants can promote ornamental plant growth during production and improve crop performance under abiotic stresses. Even though biostimulants have shown potential in many agricultural applications, the effectiveness and specificity of many products are not well understood. The objective of this study was to analyze the growth-promoting effects of microbial biostimulants during the greenhouse production of floriculture crops. We evaluated 13 biostimulant products in greenhouse-grown zinnia (Zinnia elegans ‘Magellan Ivory’) and petunia (Petunia ×hybrida ‘Carpet White’) at low fertility (one-third of the optimal fertilizer concentration). Biostimulant products 1 and 2 containing multiple species of beneficial bacteria and fungi, and product 10 containing Bacillus subtilis QST 713, were found to increase various aspects of plant growth, including the growth index, leaf chlorophyll content (SPAD index), and shoot biomass. Both flower biomass and numbers were greater in petunia treated with product 1, and leaf size increased in zinnia treated with products 1, 2, and 10. Plants treated with these effective biostimulants at low fertility had similar or better growth and quality than untreated plants grown under optimal fertility. The concentration of various nutrient elements in leaves was higher in zinnia plants treated with biostimulant products 1, 2, or 10 compared with the negative control. Some putative mechanisms for biostimulant effectiveness, the possible reasons for biostimulant ineffectiveness, and the potential for using biostimulants as a sustainable cultural strategy are discussed. This study provides useful information about microbial biostimulant effectiveness, which is important for the development and utilization of biostimulants in the greenhouse production of floriculture plants.

Five-year period of evaluation of leaf mineral concentrations in resistant varieties in Trentino (Northeastern Italy)

Recently new resistant and/or tolerant genotypes to the main cryptogams (downy and powdery mildew) were identified, to be used in enhancing sustainable viticulture. These cultivars (result of interspecific crossings between Vitis vinifera cultivars and other Vitis species of American and Asian origin) are experiencing a relevant expansion in Europe in viticultural regions characterized by high rainfall per year. In two sites of Trentino (Northeastern Italy) with different soil pH levels, and where these conditions are widespread, an important study was scheduled. During the period 2015-2019, fifteen resistant varieties were monitored in order to have information about agronomical and nutritional behavior. Yearly, at fruit set nutritional aspects through leaf analyses and leaf green color (SPAD indexes) were monitored. At pre-veraison, photosynthetically active biomass behavior (Normalized Difference Vegetation Index NDVI indexes) was controlled. Weather conditions of different years strongly changed the availability of nutrients in vines in relation to different genotypes and their color of vegetation and vigor. Collected results allow to suggest interventions aimed at a more suitable nutritional management for resistant varieties, in comparison of Vitis vinifera, above all for nitrogen (N), potassium (K), and zinc (Zn); in particular, for magnesium (Mg), early foliar treatments should be recommended, especially in years where rainfall is concentrated in the spring months.

Fertilization with different soil types in viticulture: a three-year experience in Trentino Alto Adige

The work aimed at investigating the impact of various good quality soils of on vineyard productivity. Manure matured with a fast and controlled process and compost obtained from digestate of an organic fraction of municipal solid waste (OFMSW) were applied one time on a grapevine row, in two CAVIT vineyards. A physico-chemical characterization of the soils was carried out and biological quality indices QBS-ar (Arthropodological Biocenosis) were calculated. The vegeto-productive monitoring was performed by foliar nutrients analysis and measuring NDVI and SPAD indices. The organic source had a significant fertilizing effect, especially manure, which determined a nutrient increase in soil (P, K and Mg), a rise in photosynthetically active biomass, available nitrogen and potassium in plants. The effects on the biological community of soils and musts quality were negligible. The use of soil improvers could be an efficient strategy for the nutrition of not vigorous vineyards, which do not require high nitrogen inputs.

Growth response of three forest seedlings to iron exposure

Fe is one of the microessential plants needed in low concentrations. The purpose of this study was to examine the growth response of three forest seedlings to iron exposure in water culture media. This study used a completely randomized design (CRD) with Fe dose treatment and consisted of 9 levels, namely 0, 0.5, 0.1, 1.5, and 2, with 3 replications each and each replication consisting of 3 plant units. The plants used consisted of Ochroma bicolor, Shorea macrophylla, and Senna siamea. The results of this study showed that Fe exposure treatment had a significant effect on the three seedlings on all growth parameters (height, root length, root dry weight, shoots, and total dry weight). Increasing the concentration of Fe can reduce all growth parameters. The three seedlings have different tolerance levels. Fe exposure treatment had a significant effect on the SPAD index only on O. bicolor and S. seamea seedlings. S. macrophylla seedlings had the highest tolerance index value compared to the other two seedlings. This indicated that S. macrophylla seedlings had higher resistance than the other two seedlings to Fe exposure.

Salicylic acid mitigating damage to the photosynthetic apparatus and quality of Eugenia myrcianthes seedlings under water deficit

Abstract This study aimed to evaluate the effect of exogenous application of salicylic acid on the photosynthetic metabolism and quality of Eugenia myrcianthes seedlings under water deficit and their recovery potential after rehydration. Two water regimes were evaluated, as follows: control - plants irrigated daily (I) and water deficit (S), with and without the application of 400 mg L–1 of salicylic acid (SA), totaling four treatments. Seedlings were evaluated at three times: at the beginning of the experiment (T0), that is, when the irrigation was interrupted; when the photosynthetic rate reached values close to zero (P0 - 15 days after irrigation interruption), that is, when irrigation restarted; and when the photosynthetic rate was recovered (REC). Eugenia myrcianthes seedlings were negatively affected when subjected to water restriction; salicylic acid attenuated the damage to the photosynthetic apparatus by acting positively on the relative water content in the leaves, SPAD index, photosynthetic metabolism, superoxide dismutase and peroxidase enzyme activity, and seedling growth in P0. Eugenia myrchiantes presented potential for recovery after resumption irrigation. The application of SA contributed to the maintenance of gas exchanges, photochemical processes and quality of E. myrcianthes seedlings during and after water deficit, suggesting the promotion of plant resistance induction.

Genetic and symbiotic characterization of rhizobia nodulating legumes in a mining area in southeast Brazil

Identification and selection of nitrogen-fixing bacterial strains for inoculation into native leguminous tree species can assist in the recovery of degraded areas. Additionally, native strains from these areas are genetic resources adapted to these conditions and are thus suitable for selection. The aim of this study was to symbiotically and genetically characterize 18 bacterial strains from the Rhizobium and Bradyrhizobium genera isolated from Machaerium nyctitans, Platypodium elegans, and Ormosia arborea grown in a nursery in an iron mining area. Three experiments were conducted under axenic conditions in a greenhouse. The nodulation capacity of the strains was evaluated by the number (NN) and dry matter (NDM) of nodules. Symbiotic efficiency was evaluated based on the following parameters: SPAD index (SPAD), shoot dry matter (SDM), root dry matter (RDM), and total dry matter (TDM) of the plants, relative efficiency (RE), shoot nitrogen content (SNC), and total nitrogen content in the plant (TNC). The atpD and gyrB housekeeping genes and the nifH gene were sequenced for phylogenetic analysis, and the nodC and nodD symbiotic genes of the strains were amplified. Out of the 18 strains, 16 were authenticated by nodulation capacity in the species of origin. The SPAD variable allowed for the detection of differences between treatments before the SDM. Additionally, the SPAD index showed correlation with TNC, and the strain Bradyrhizobium sp., UFLA01-839, which may represent a new species, was outstanding in Machaerium nyctitans. The nifH, nodD, and nodC genes were detected in UFLA01-839.

Efficient management of fertilizer nitrogen in spring maize using spad chlorophyll meter and greenseeker optical sensor

Over-application of fertilizer nitrogen (N) in spring maize results in low fertilizer N use efficiency. Site specific need-based fertilizer N management in spring maize using chlorophyll meter (SPAD meter) and GreenSeeker optical sensor was compared with soil-test recommended N applications in field experiments conducted for two years during 2017 and 2018. Treatments consisted of different rates of N application based on SPAD and GreenSeeker sufficiency index approaches and soil-test based recommended N applications. The results showed that N application using SPAD based on sufficiency index of 0.95 and GreenSeeker based on 0.90 sufficiency index criteria not only produced significantly higher yields but also increased total N uptake by 10.7% to 15.0% than soil-test based fertilizer N recommendation with fertilizer N dose of 120 kg N ha−1. Significantly higher N recovery and agronomic efficiencies were observed when N was applied using SPAD and GreenSeeker based sufficiency index approaches. The results of this study suggested that to avoid over application of N and to obtain high yields and N-use efficiencies in spring maize fertilizer N application should be guided by sufficiency index approach that indicate N deficiency or sufficiency for the crop.

Resposta de espinafre-brasileiro (Alternanthera sissoo) ao material de propagação e à aplicação de fertilizante NPK

ABSTRACT Alternanthera sissoo is currently propagated using stem or terminal cuttings, since it does not produce fertile seeds. This research aimed to identify the most effective propagation planting material among rooted stump, stem cutting and terminal cutting, as well as their response to the application of NPK fertilizer. The results showed a better performance for stem cutting than for rooted stump or apical cutting. The canopy area was positively related to the longest diameter (R2 = 0.92) and the average of two-way cross-sectional diameter (R2 = 0.89). The number of branches, branch fresh weight, leaf fresh and dry weights did not vary among the planting materials; however, the total number of leaves, branch and root dry weights were higher for stem cutting. Stem cutting is also available in a larger quantity than the other two planting materials when collected from each mother plant. Therefore, it is recommended for optimizing leaf yield in A. sissoo. The species positively responded to NPK fertilization, as shown by the increase of the SPAD value for 6 to 12 days after the initial application. Therefore, for maximizing yield, it should be regularly fertilized with NPK every 3 weeks, coinciding with the time that the SPAD index falls back to pre-NPK application levels.

Primena SPAD u proceni sadržaja hlorofila različitih srpskih provenijencija hrasta kitnjaka

Chlorophyll is the main participant in the process of photosynthesis, which content can tell about plant physiological health condition. In this research, the SPAD values of the one-year-old Sessile oak seedlings of 5 Serbian provenances were measured during June, August, and October of 2021. The measuring was performed by the SPAD device, and the data were presented through the SPAD index values. The research results confirmed that the environmental conditions where the plants grow have a dominant effect on the chlorophyll content, concerning the origin of the individuals. In further research, it is necessary to accurately determine on a greater plant sample the relationship between chlorophyll content and SPAD index values.

Molybdenum increases nitrogen use efficiency of sugarcane under limited N supply

The application of nitrogen (N) is a major challenge for sugarcane production due to the low nitrogen use efficiency (NUE). A possible key to increasing the NUE in sugarcane is the adequate supply of molybdenum (Mo) due to their role in nitrate reductase (NR) activity and N metabolism within plant tissue. We hypothesized that Mo supply increases NUE in sugarcane by improving NR activity and dry matter production. Our aim here was to test the combined application of N and Mo on sugarcane plantlets to evaluate the NR activity, biomass production, contents of N and Mo in leaves, and NUE. A growth-chamber experiment was run using N rates (Control; 30; 60; 120 and 240 mg kg−1) and Mo supply (Control and 0.5 mg kg−1) with four replications. Measurements of biomass production, NR activity, N and Mo content in leaves, SPAD index, and NUE were evaluated after 54 days of cultivation. Nitrogen rates increased biomass production, N-content in leaves, SPAD index and NR activity in the absence of Mo supply. Mo supply didn’t affect NR activity in leaves, but increased 48% the NUE at the lowest N rate (30 mg kg−1), suggesting a positive effect of Mo in another pathway of N metabolism. Our results suggest that the Mo application increases NUE under limited conditions of N supply by affecting other N-metabolism process rather than NR activity. Mo uptake increased with N doses, reaching maximum Mo-leaf contents of 17.5 mg kg−1 at the 151.2 mg kg−1 N rate. HIGHLIGHTS Nitrogen rates consistently increases biomass production and N nutrition of sugarcane plantlets Mo supply increases Mo-leaf content but does not affect NR activity Mo supply increases nitrogen use-efficiency under limited N supply.