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Data Brief
Data Brief
Data in Brief
2352-3409
Elsevier

S2352-3409(24)00853-9
10.1016/j.dib.2024.110890
110890
Data Article
Morpho-physiological and anatomical responses of two Urochloa hybrids under shade: Dataset article
Hernández Álvarez Urys Mileth abc
Mayorga Mildred m.mayorga@cgiar.org
b⁎
Cardoso Arango Juan Andrés @grass_scientist
b
a Facultad de Ciencias Agrarias, Universidad Nacional del Litoral, Kreder 2805 Esperanza, Santa Fe, Argentina
b Tropical Forages Program, International Center for Tropical Agriculture (CIAT). Km 17 recta Cali- Palmira, CP 763537, Colombia
c Instituto Nacional de Tecnología Agropecuaria (INTA), Instituto de Fisiología y Recursos Genéticos Vegetales, Unidad de Estudios Agropecuarios (INTA-CONICET), Av. 11 de Septiembre 4755 (X5020ICA), Córdoba, Argentina
⁎ Corresponding author. m.mayorga@cgiar.org
31 8 2024
12 2024
31 8 2024
57 11089011 6 2024
22 8 2024
26 8 2024
© 2024 The Authors
2024
https://creativecommons.org/licenses/by-nc/4.0/ This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).
Silvopastoral systems are an important strategy for sustainable livestock production. However, to expand their implementation, it is crucial to identify and develop forage materials that maintain good production and quality while being tolerant to shade conditions as well as other biotic and abiotic stresses. A field trial was conducted to evaluate the morpho-anatomical and agronomic responses of two Urochloa hybrids (Camello and Talisman) under two light conditions: shade (28 % light intensity) and full exposure. The trial followed a randomised complete block design with split-plot arrangement, where each treatment corresponded to a plot with three replications. Morphological and anatomical parameters were recorded in three technical replicates of each replication. Histological leaf sections were analysed for the percentage of adaxial epidermis, abaxial epidermis, vascular tissue, colourless parenchyma, Kranz sheath, bulliform cells, sclerenchyma, and chlorenchyma. Measurements in leaf included relative chlorophyll concentration, leaf area, leaf length, and leaf width. Evaluations in plant included height and number of tillers. Agronomic parameters such as plant cover and dry biomass were recorded for each plot. Additionally, six leaf imprints were made on the leaf undersides to observe stomatal morphology, and their length was recorded. Furthermore, plants from each treatment were grown in soil-filled tubes within the same plots. Root system photographs were taken, and in three replications per treatment, root length, root diameter, root volume, root surface area, and the depth at which 95 % of roots were concentrated (D95) were determined. These data can be utilised by the scientific community and breeders to conduct analyses and meta-analyses to identify shade tolerance mechanisms and develop genetic materials tolerant to changing climatic conditions while being optimal for use in silvopastoral systems.

Keywords

Shade tolerance
Plant anatomy
Root system
Forage
Silvopastoral systems
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pmcSpecifications TableSubject	Agricultural Sciences	
Specific subject area	Agronomy and Crop Science	
Type of data	Table, Figure	
Data collection	Data on Urochloa hybrids related to morphological, agronomic, physiological, and anatomical traits were collected under field in two conditions of light (28 % and 100 % light intensity). The forages were in a vegetative state the data were collected at plant and plot based on the nature of the parameter. The proportions of the different types of anatomical tissue were expressed as a percentage of the transversal section. Images of inverted optical microscope (Leica DMi8) in JPEG format (1946 × 1468 pixels) digitized in (300dpi). Root images were taken in a dark room using a Canon EOS Mark II reflex camera, then processed with ImageJ and analysed with RhizoVision Explorer. Evidence of a normal distribution and the homogeneity of variances were tested [1,2] before analysis. Principal component analysis was carried out with morphological, agronomic, physiological, and anatomical traits. The data was standardised before data analysis [3]. The results of a principal component analysis were visualised through biplot graphs [4] digitized in (300dpi), in JPEG format (1845×1464 pixels).	
Data source location	The International Center for Tropical Agriculture is the owner of the data presented in this article. The experimental site is located at a longitude of 3° 50′ 38″ North and 76° 35′ 36″ West with an altitude of 994 m above sea level.	
Data accessibility	Repository name: Harvard Dataverse
Data identification number: doi:10.7910/DVN/FOHK4X [5]
Direct URL to data: https://dataverse.harvard.edu/dataset.xhtml?persistentId=doi:10.7910/DVN/FOHK4X	

1 Value of the Data

• Adaptation to climate change requires the development and implementation of sustainable livestock systems that minimize the negative impact of agricultural production on the environment and extreme temperatures on animal welfare and production. One of the main strategies of sustainable livestock is the establishment of silvopastoral systems, which combine tree growth with forage production for livestock. Trees, in addition to sequestering CO2, generate a cooler microclimate for animals and can also be used for animal feed.

• Camello cultivar is a Urochloa hybrid developed by the CIATʼs tropical forage breeding program. It is characterized by high biomass production, thanks to its high growth rate and high leaf-to-stem ratio; it also has good nutritional quality and tolerance to drought stress, due to the architecture of its root system, which allows it to explore deep soil layers to extract water during dry periods.

• Talisman cultivar is another Urochloa hybrid developed by the CIATʼs tropical forage breeding program. It has shown a good response in forage production and nutritional quality under shaded conditions, compared to other commercial cultivars.

• Evaluating the response of improved forage hybrids to shade conditions is important for identifying materials with potential for use in silvopastoral systems. Likewise, measurements of parameters related to leaf and root anatomy and morphology are a useful tool for scientists and breeders as they allow for a better understanding of some of the mechanisms that confer tolerance to this shade condition. This understanding enables their inclusion in the selection and development processes of improved materials that are later released commercially for use by livestock farmers.

2 Background

Livestock contributes to global warming as one of the main emitters of methane. Additionally, it is affected by it, as high temperatures and frequent drought seasons cause stress to both forage plants and animals, reducing forage biomass production, as well as meat and milk production. Silvopastoral systems combine the growth of trees and forage for livestock production, serving as an alternative that partially offsets greenhouse gas emissions through CO2 captured by tree component and deep-rooted grasses. Moreover, they contribute to mitigating the adverse effects of climate change by generating microclimates with less extreme conditions due to tree shading.

Hybrids of Urochloa with optimal production and forage quality characteristics have been developed. Among these, Camello stands out as an adaptation response to climate change, being drought tolerant. Given the advantages of this cultivar, understanding its response to shaded conditions is important to determine its potential for use in silvopastoral systems. Talisman is another improved hybrid characterised by its shade tolerance, making it an ideal material for comparison with other materials in terms of shade tolerance.

3 Data Description

The dataset from the linked repository was compiled from a field trial conducted between July and December 2023 in the Americas hub of The Alliance of Bioversity International and CIAT (Palmira, Colombia). The measurements correspond to three repetitions with a different number of biological replicates performed on plants of two hybrid Urochloa cultivars grown under shade and full exposure. Table 1 displays the leaf anatomical characteristics of the Urochloa hybrids Camello and Talisman under two light conditions (with shade: 28 % light intensity and without shade: 100 % light intensity). Table 2 presents morpho-agronomic characteristics of the two cultivars grown under these conditions. In Table 3, the relative chlorophyll content and stomatal length of the two hybrids with and without shade condition are observed. Table 4 records the root characteristics of the two materials grown under shade and full exposure. Fig. 1 illustrates a cross-section of the leaf of each of the two cultivars under the two light conditions, and Fig. 2 displays a principal component analysis that includes the morpho-agronomic characteristics, leaf anatomy, and root morphology of the treatments.Table 1 Foliar anatomical traits expressed in percentage (%) of the cross section of leaf blades of two Urochloa hybrids (Camello and Talisman) grown in two conditions: under shade and without shade (Control).

Table 1Anatomical parameter	Control	Shade	
Camello	Talisman	Camello	Talisman	
Adaxial epidermis	3.29 ± 0.12 a	3.32 ± 0.16 a	3.63 ± 0.15 a	3.33 ± 0.19 a	
Abaxial epidermis	5.46 ± 0.23 b	6.02 ± 0.19 ab	5.95 ± 0.23 ab	6.48 ± 0.33 a	
Kranz sheath	21.29 ± 0.34 a	19.29 ± 0.78 b	19.56 ± 0.48 ab	20.21 ± 0.4 ab	
Vascular tissue	11.97 ± 0.29 a	8.76 ± 0.28 c	10.72 ± 0.17 b	7.96 ± 0.15 c	
Bulliform cell	4.69 ± 0.43 c	7.58 ± 0.5 b	9.01 ± 0.4 b	11.59 ± 0.39 a	
Sclerenchyma	3.64 ± 0.11 a	2.76 ± 0.12 b	3.49 ± 0.12 a	2.77 ± 0.24 b	
Colourless parenchyma	21.47 ± 0.43 b	18.16 ± 0.82 c	25.75 ± 1.16 a	19.43 ± 0.59 bc	
Chlorenchyma	28.2 ± 0.98 b	34.32 ± 1.3 a	21.89 ± 1.06 b	28.23 ± 0.96 a	
Different letters indicate significant differences for two-way interaction (genotype * treatment) according to the Tukey test (P ≤ 0.05). Data are expressed as means ± SEM (n = 3).

Table 2 Morphological and agronomic parameters of two Urochloa hybrids (Camello and Talisman) grown in two conditions: under shade and without shade (Control).

Table 2Morphological and agronomic parameter	Control	Shade	
	Camello	Talisman	Camello	Talisman	
Leaf length (cm)	27.28 ± 0.3 b	24.56 ± 0.62 c	30.97 ± 0.63 a	25.22 ± 0.89 bc	
Leaf width (cm)	1.78 ± 0.04 a	1.83 ± 0.02 a	1.5 ± 0.02 b	1.46 ± 0.04 b	
Leaf area (cm2)	29.49 ± 1.79 a	16.96 ± 1.47 c	29.21 ± 1.55 a	23.57 ± 0.91 b	
Plant cover (m2)	16.36 ± 1.91 a	16.57 ± 0.23 a	7.77 ± 0.19 b	7.02 ± 0.21 b	
Tillers (n)	27.22 ± 1.37 b	33.22 ± 0.78 a	9.78 ± 0.52 c	11.56 ± 0.47 c	
Dry matter (%)	27.81 ± 0.56 a	25.87 ± 0.3 a	26.63 ± 1.46 a	24.19 ± 0.72 a	
Plant height (cm)	31.01 ± 0.99 a	24.68 ± 1.34 b	34.46 ± 2.69 a	36.1 ± 0.79 a	
Different letters indicate significant differences for two-way interaction (genotype * treatment) according to the Tukey test (P ≤ 0.05). Data are expressed as means ± SEM (n = 3).

Table 3 Relative Chlorophyll Concentration (RCC) and stoma length of two Urochloa hybrids (Camello and Talisman) grown in two conditions: under shade and without shade (Control).

Table 3Physiological parameter	Control	Shade	
	Camello	Talisman	Camello	Talisman	
RCC	58.01 ± 3.15 a	63.66 ± 8.63 a	36.29 ± 1.69 b	35.91 ± 2.79 b	
Stoma length (µm)	24.52 ± 0.64 ab	26.44 ± 0.3 a	22.43 ± 0.98 b	25.97 ± 0.73 a	
Different letters indicate significant differences for two-way interaction (genotype * treatment) according to the Tukey test (P ≤ 0.05). Data are expressed as means ± SEM (n = 3).

Table 4 Root traits of two Urochloa hybrids (Camello and Talisman) grown in two conditions: under shade and without shade (Control).

Table 4Root trait	Control	Shade	
Camello	Talisman	Camello	Talisman	
D95 (cm)	81.67 ± 3.73 a	86.11 ± 6.33 a	55 ± 5.27 b	78.33 ± 5.77 a	
Length (cm)	884.36 ± 103.08 a	947.31 ± 113.9 a	301.23 ± 59.01 b	715.08 ± 34.07 a	
Diameter (cm)	1.88 ± 0.09 ab	1.99 ± 0.13 a	1.64 ± 0.06 b	1.77 ± 0.06 ab	
Volume (cm3)	35.94 ± 6.79 ab	48.62 ± 9.82 a	8.81 ± 1.91 c	23.73 ± 2.67 cb	
Area (cm2)	532.1 ± 71.61 a	616.84 ± 92.56 a	164.34 ± 33.31 b	402.48 ± 26.45 ab	
Different letters indicate significant differences for two-way interaction (genotype * treatment) according to the Tukey test (P ≤ 0.05). Data are expressed as means ± SEM (n = 3).

Fig. 1 Response to shade conditions on anatomical parameters measured in two Urochloa hybrids (Camello and Talisman). Transversal section of leaf blades of Camello without shade (A) and under shade (B), and Talisman without shade (C) and under shade (D). —scale bar 50.5 µm. Adaxial epidermis (Ad.Ep); Abaxial epidermis (Ab.Ep); Vascular tissue (VT); Sclerenchyma (S); Bulliform cells (BC); Kranz sheath (KS); Colourless parenchyma (CP); Chlorenchyma (C).

Fig. 1

Fig. 2 Biplot showing the differences between two Urochloa hybrids (Camello and Talisman) grown in two conditions: under shade and without shade (Control) in morphological, agronomic, physiological, and anatomical traits. Abbreviations: Abaxial epidermis (Ab.Ep); Chlorenchyma (C); Sclerenchyma (S); Kranz sheath (KS); Vascular tissue (VT); Bulliform cells (BC); Colourless parenchyma (CP); Leaf length (LL); Leaf width (LW); Leaf area (LA); Dry matter (DM); Plant cover (PC); Tillers for plant (T) and Relative chlorophyll concentration (RCC).

Fig. 2

4 Experimental Design, Materials and Methods

4.1 Site descriptions and experimental design

The field and laboratory evaluations were carried out on the Bioversity- Alliance Campus- located in Palmira Valle del Cauca 3° 50′ 38″ N - 76° 35′ 36″ W. In the months of July to December 2023. A factorial combination of two hybrids (Talisman and Camello) by two shading conditions (shade: 28 % light intensity and no-shade: 100 % light intensity) in a three-replicate complete randomised block was established in the field. The trial was organised in divided plots, where the main plot was the light level, and the subplots were the hybrids. The experimental unit consisted of a plot of 2.25 m2 containing 25 plants, with a spacing of 0.3 m between plants and 2 m between plots. The shading condition was provided by installing a shade net located 2 m above ground level. The planting material used were seedlings germinated previously in a substrate containing peat.

The soil is a vertisol, loamy-sandy texture, pH 7.7, oxidizable carbon 13.74 g kg-1, organic matter 31.20 g kg-1, phosphorus 140.05 mg kg-1, calcium 19.93 cmol/kg, magnesium 7.21 cmol/kg, potassium 0.75 cmol/kg. During the trial span, the average temperature was 26.4 °C, the relative humidity was 77.8 %, and the precipitation was 389.6 mm.

4.2 Morphological and agronomic traits

The morphological and agronomic traits were evaluated when the plants were vegetative stage. Plant height was measured from the base to the end of the plant. For leaf length, leaf width and leaf area they were cutting the fourth leaf youngest of three plants per genotype per block and were evaluated with the software Hoja 3.6 [6]. For plant cover, a photograph was taken per each block and measured using ImageJ. The percentage forage dry matter was evaluated by cutting at 20 cm above the soil six plants per block per hybrid. The samples were weighed fresh and then were dried in a forced air oven (Memmert) at 60 °C until to obtain weight constant and dry weight was measured using a balance (Scientech - SA 210D). The dry weight was related to the fresh weight to calculate the percentage of dry matter. The tillers of three plants per hybrid per block were counted.

4.3 Anatomical traits

Segments of 2 cm from the base of the third fully expanded leaf were preserved in 70 % ethanol. Samples were placed in 5 % agar. Transversal cuts were made using vibrating blade microtome (Leica VT1000 S) cross sections of leaf (100 µm thick). Relative tissues were identified using a light microscope (Leica DMi8) and the pictures were captured at magnifications of 10×. Measurements were performed in three plants (three cross sections per sample). Three vascular bundles on each side of the central bundle were considered for leaf blade measurements, according to Hernández et al. [7]. Tissue proportion was measured: adaxial epidermis, abaxial epidermis, vascular tissue, sclerenchyma, bulliform cells, Kranz sheath, colourless parenchyma, chlorenchyma. Chlorenchyma was calculated by the difference between the total area and the area of the above tissues. Images were analysed using ImageJ (Image Processing and Analysis in Java) [8]. The proportions of the different types of tissue were expressed as a percentage of the transversal section.

4.4 Physiological traits

Relative chlorophyll concentration was measured using Chlorophyll Meter SPAD-502Plus (Konica Minolta). This trait was estimated of three plants by experimental unit. At the third fully expanded leaf, in the mid-section between the edge and the main nerve of the leaf. Measurement was taken at 11am to avoid reading error by water droplets on the leaf. Stoma length (SL) was measured on the fourth leaf blade of three plants (six stomas) by experimental unit in the mid-section between the edge and the main nerve of the leaf. Measurements were made using a light microscope and the pictures were captured at magnifications of 20×. Images were analysed using ImageJ.

4.5 Root morphological traits

Transparent plastic tubes with a diameter of 3″ and length of 1.1 m, sealed at the bottom, were filled with 7.7 kg of a soil–sand mixture in a 2:1 ratio. The soil used was a sandy loam vertisol with a pH of 7.5 obtained from CIAT Palmira campus. Holes were made at the bottom of each plastic tube to allow water drainage, and they were then placed inside PVC tubes to create conditions of darkness for the rhizosphere. Each tube was planted with a vegetative propagule of the corresponding hybrid according to the experimental design. The tubes were arranged in racks to maintain a vertical position. Plants were watered 2–3 times per week, maintaining field capacity, and were fertilised with two grams of a mixture containing 18.1% N, 14.5 % P2O, and 24.8% K.

In each photograph, the rectangle corresponding to the soil with the roots was cropped and segmented using ImageJ. The resulting image was then analysed in RhizoVision Explorer [9] to obtain root length, root diameter, root volume, and root surface area data. Each root image was divided into 11 segments (0–10, 10–20, 20–30, 30–40, 40–50, 50–60, 60–70, 70–80, 80–90, 90–100, 100–110 cm) using ImageJ, and the root surface area of each segment was determined using RhizoVision Explorer. With the obtained information, the D95 was calculated as the depth at which 95 % of the roots are concentrated.

4.6 Statistical data analysis

With the collected data, normal distribution and homogeneity of variances were verified using residuals. For each dependent variable, a two-way analysis of variance (ANOVA) and Tukeyʼs test for mean comparison (P < 0.05) were conducted. R-Studio statistical software (R version 4.3.0) [10] was used for the analysis.

Limitations

No limitations related to the data collection or curation were encountered.

Ethics Statement

The dataset collected in this study did not involve human subjects, animal experiments, or any data collected from social media platforms.

CRediT Author Statement

Urys Mileth Hernández Alvarez and Mildred Mayorga: conceptualization, methodology, validation, formal analysis, investigation, data curation, writing - original draft preparation, visualization. Juan Andrés Cardoso Arango: conceptualization, methodology, validation, formal analysis, investigation, data curation, visualization, supervision, writing - reviewing and editing.

Data Availability

Data on Morpho-physiological and anatomical responses of two Urochloa hybrids under shade (Original data) (HARVARD Dataverse).

Acknowledgements

This study was funded by the CGIAR Initiatives on Sustainable Animal Productivity for Livelihoods, Nutrition and Gender inclusion (SAPLING), and Livestock and Climate. This study is part of the project “Using genetic diversity in deep root systems of forage grasses and rice to capture carbon in tropical soils”, supported by the Bezos Earth Fund. We thank all donors that globally support the work of the Initiatives through their contributions to the CGIAR system.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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