DOI: 10.5061/dryad.xwdbrv1q8
title: Evaluating the combined effects of light and water availability on the early growth and physiology of Tamarindus indica: Implications for restoration

description: Premise: The tamarind tree (Tamarindus indica L.), is a species of
 significant cultural, economic, and ecological value, with a pantropical
 distribution. However, the tamarind is experiencing a decline in wild
 populations in its native range, but the reasons for its decline remain
 unknown. Methods: We examined the critical early life history stages for
 tamarind establishment to understand how varying levels of light and water
 availability and watering frequency affect its regeneration. Through three
 greenhouse experiments we assessed the impact of these resources on the
 germination, survival, growth, and physiological responses or tamarind
 seedlings and saplings. Results: Water availability was critical for seed
 germination, but not light levels or pre-germination treatments. Light was
 the primary limiting factor for seedling growth. Tamarinds in high light
 availability grew taller, had a higher biomass and a larger diameter, but
 this effect was modulated by water availability, indicating that there was
 an interaction between both resources. Water and light affected specific
 leaf area and leaf dry matter content but not biomass allocation,
 root-to-shoot ratio, or stomatal conductance. Water availability
 influenced sapling growth, but watering frequency did not, indicating a
 resilience of tamarind saplings to changes in rainfall periodicity but a
 sensitivity to total rainfall amounts. Conclusions: Our study underscores
 the importance of considering both light and water availability in
 tamarind restoration efforts and contribute to understanding plant
 responses and trade-offs under different levels of critical resources. Our
 findings inform conservation strategies to support the regeneration and
 long-term survival of Tamarindus indica in its native habitats. 
description: This data was collected from experiments conducted in a
 greenhouse at the University of Minnesota. The available data is the data
 gathered during the course of the experiments. Three different experiments
 were carried. The first one was a seed germination experiment. For the
 second one, we employed tamarind seedlings and for the third one tamarind
 saplings. The data was recorded in excel files and has not been
 transformed. 
description: # Evaluating the combined effects of light and water availability on the
 early growth and physiology of Tamarindus indica: Implications for
 restoration
 [https://doi.org/10.5061/dryad.xwdbrv1q8](https://doi.org/10.5061/dryad.xwdbrv1q8) ## Description of the data and file structure ### Tamarindus indica seed germination and early growth This dataset contains three files with the results of three greenhouse experiments designed to assess the impact of two critical resources, light and water, on the germination, survival, growth, and physiological responses of tamarind seedlings and saplings. 1. The file "Tamarind germination" contains the data of the first experiment designed to evaluate the germination responses of tamarind seeds under varying light and water conditions. We sowed 300 seeds in germination trays filled with Sungro Professional Growing Mix, positioning them approximately 5 mm below the surface. The seeds, with an average mass of 1.05 g, were distributed across three light treatments—low, medium, and high light—created using shade houses of PVC pipes and shade cloths to simulate forest-like conditions. The light intensities were measured in terms of photosynthetic photon flux (PPF) and varied as follows: full light at 970 μmol m^−2 s^−1 (open forest areas), medium light at 120 μmol m^−2 s^−1 (small forest gaps), and low light at 9 μmol m^−2 s^−1 (closed canopy). Seed germination was monitored for 30 days post-sowing to determine the effects of light, water, and scarification treatments on germination rates. 2. The file "Tamarind seedling growth" presents the data of our second experiment that was designed to assess how different levels of light and water influence the growth and survival of tamarind seedlings. This experiment involved 300 tamarind seedlings grown in a full factorial design, combining three light levels (as established in Experiment 1) with four different watering regimes. The seedlings were sourced similarly to those in the first experiment, with an average seed mass of 1.06 g. Each light treatment had 100 seedlings. These seedlings were classified as plants younger than three months that had not yet dropped their cotyledons. Within each light category, seedlings were subjected to one of four watering treatments—no water, low, medium, and high—distributed evenly across 25 seedlings per light and water combination. Seedlings were planted in 1-gallon pots using a soil mix of 40% black soil, 30% sand, and 30% composted pine bark, and fertilized with 23 grams of slow-release Osmocote Plus (15N:9P:11K). Over four months, measurements were taken weekly to track seedling survival, stem diameter, and height. At the experiment's conclusion, seedlings were harvested and their fresh and dry biomass was measured. This biomass data is contained in the file.  3. The file "Tamarind sapling growth" has the data which explored the influence of water availability and watering frequency on the early growth of tamarind saplings. In this experiment, a total of 150 tamarind saplings, cultivated from an independent batch of seeds, participated in this experiment. These saplings were defined as such due to their age of six months, woody stems, and absence of cotyledons. Initially, all saplings were grown under uniform conditions in one-gallon pots containing a mixture of 40% black soil, 30% sand, and 30% composted pine bark, fertilized with 23 grams of Osmocote Plus. They received a consistent initial watering regime of three times per week for the first three months. After three months of uniform growth conditions, the saplings were distributed into four different watering treatments, each comprising 25 plants. These treatments mirrored those used in Experiment 2 (no water, low, medium, and high watering). Alongside the standard treatments, two groups of saplings within the medium watering category were subjected to varied watering frequencies: * **Group 1**: Received the total weekly water allotment in a single weekly session. * **Group 2**: Water was distributed bi-weekly, ensuring the same total weekly volume as Group 1 but administered less frequently. These treatments lasted for three months. At the end of this period, all saplings were harvested, and detailed assessments were conducted to evaluate their growth and physiological traits, focusing on how water stress and frequency of watering influenced sapling development. ## Description of the data and file structure A. File "Tamarind germination" All the data are contained in columns/rows and each row represents a seed.  The following is a description of the columns: 1. Seed_identifier: a column that contains a unique number to identify each seed used 2. Watered: this column indicates wether the seed was watered (1) or not watered (0) during the experiment 3. Scarified: this column indicates wether the seed was scarified (1) or not (0) during the experiment. Scarification was achieved doing little cuts to the seed coat with a nail clipper (nicking). 4. Light: this column indicates the light treatment that the seed was subjected to. The options are low light, medium light or high light.  5. Germination:  this column indicates wether the seed germinated (1) or not (0) during the experiment. B. File "Tamarind seedling growth" All the data are contained in columns/rows and each row represents an individual tamarind seedling.  The following is a description of the columns: 1. Individual: a unique number to identify each seedling. 2. Water treatment: treatment category indicating the water volume (in mililiters) per watering event. No water: 0 mililiters; Low water: 70 mililiters; medium water: 281 ml; high water 563 mililiters 3. Light: this column refers to the light treatment under which the seedlings were grown. The light intensities were measured in terms of photosynthetic photon flux (PPF) and were the following: full light 970 μmol m^−2 s^−1; medium light 120 μmol m^−2 s^−1; low light 9 μmol m^−2 s^−1.  4. Height_final: total height of each sapling in centimiters, measured from the root collar to the apical meristem at the end of the experiment, previous to harvesting the plants. 5. Diameter_final: diameter of the stem in milimiters, measured at the root collar 6. Fresh leaves mass: Total mass of the leaves (in grams) weighed inmediately after harvesting 7. Dry leaves mass: Total mass of the leaves (in grams) weighed after the seedlings were oven dried for at least 48 hours, or untill they achieved a constant weight. 8. Fresh stem mass: Total mass of the stem (in grams) weighed inmediately after harvesting 9. Dry stem mass: Total mass of the stem (in grams) weighed after the seedlings were oven dried for at least 48 hours, or untill they achieved a constant weight. 10. Fresh root mass: Total mass of the root (in grams) weighed inmediately after harvesting 11. Dry root mass: Total mass of the root (in grams) weighed after the seedlings were oven dried for at least 48 hours, or untill they achieved a constant weight. 12. total_aboveground_mass: total mass of the aboveground structures of the seedling (in grams). Obtained by adding dry leaves and dry stem mass 13. DRY_WHOLE_PLANT_BIOMASS: total mass of the sapling after drying (in grams). It is the sum of the dry mass of the leaves, root and stem. 14. SMF: Stem mass fraction: This metric represents the proportion of a plant's total dry biomass that is attributable to the stem. It is calculated by dividing the dry weight of the stem by the total dry biomass of the plant. 15. LMF: Leaf mass fraction: This metric represents the proportion of a plant's total dry biomass that is attributable to the leaves. It is calculated by dividing the dry weight of the leaves by the total dry biomass of the plant. 16. RMF: Root mass fraction: This metric represents the proportion of a plant's total dry biomass that is attributable to the root. It is calculated by dividing the dry weight of the root by the total dry biomass of the plant. 17. RSR: Root to shoot ratio: Calculated by dividing the total root dry mass by the total aboveground biomass. 18. Stomatal density: Stomatal density refers to the number of stomata (pores) per unit area on the surface of leaves. Measured as the count of stomata per square millimeter (stomata per mm²). 19. FvFm: Fv/Fm, or the maximum quantum efficiency of Photosystem II, is a ratio derived from chlorophyll fluorescence measurements. It is calculated using the formula Fv/Fm=(Fm−Fo)/FmFv/Fm = (Fm - Fo)/FmFv/Fm=(Fm−Fo)/Fm, where FmFmFm (maximum fluorescence) and FoFoFo (minimum fluorescence) C. File "Tamarind sapling growth" All the data are contained in columns/rows and each row represents an individual tamarind sapling.  The following is a description of the columns: 1. Individual: a unique number to identify each sapling. 2. Water treatment:  treatment category indicating the water volume (in mililiters) per watering event. No water: 0 mililiters; Low water: 70 mililiters; medium water: 281 ml; high water 563 mililiters; once week: seedlings were watered with 281 ml but water was administered only once a week; biweekly: seedlings were watered with 281 ml but water was administered only once every two weeks 3. Final height: total height of each sapling in centimiters, measured from the root collar to the apical meristem at the end of the experiment, previous to harvesting the plants. 4. final Diameter: diameter of the stem in milimiters, measured at the root collar 5. Fresh leaves mass: Total mass of the leaves (in grams) weighed inmediately after harvesting 6. Fresh root mass: Total mass of the root (in grams) weighed inmediately after harvesting 7. Fresh stem mass: Total mass of the stem (in grams) weighed inmediately after harvesting 8. Dry leaves mass: Total mass of the leaves (in grams) weighed after the seedlings were oven dried for at least 48 hours, or untill they achieved a constant weight. 9. Dry stem mass: Total mass of the stem (in grams) weighed after the seedlings were oven dried for at least 48 hours, or untill they achieved a constant weight. 10. Dry root mass: Total mass of the root (in grams) weighed after the seedlings were oven dried for at least 48 hours, or untill they achieved a constant weight. 11. Total_aboveground_biomass:  total mass of the aboveground structures of the seedling (in grams). Obtained by adding dry leaves and dry stem mass 12. Total_Dry: total mass of the sapling after drying (in grams). It is the sum of the dry mass of the leaves, root and stem. 13. LMF: Leaf mass fraction: This metric represents the proportion of a plant's total dry biomass that is attributable to the leaves. It is calculated by dividing the dry weight of the leaves by the total dry biomass of the plant.  14. SMF: Stem mass fraction: This metric represents the proportion of a plant's total dry biomass that is attributable to the stem. It is calculated by dividing the dry weight of the stem by the total dry biomass of the plant. 15. RMF: Root mass fraction: This metric represents the proportion of a plant's total dry biomass that is attributable to the root. It is calculated by dividing the dry weight of the root by the total dry biomass of the plant. 16. RSR: Root to shoot ratio: Calculated by dividing the total root dry mass by the total aboveground biomass. ### Files and variables #### File: Tamarind\_germination.xlsx All the data are contained in columns/rows and each row represents a seed.  The following is a description of the columns: 1. Seed_identifier: a column that contains a unique number to identify each seed used 2. Watered: this column indicates wether the seed was watered (1) or not watered (0) during the experiment 3. Scarified: this column indicates wether the seed was scarified (1) or not (0) during the experiment. Scarification was achieved doing little cuts to the seed coat with a nail clipper (nicking). 4. Light: this column indicates the light treatment that the seed was subjected to. The options are low light, medium light or high light.  5. Germination:  this column indicates wether the seed germinated (1) or not (0) during the experiment. #### File: Tamarind\_seedling\_growth.xlsx All the data are contained in columns/rows and each row represents an individual tamarind seedling.  The following is a description of the columns: 1. Individual: a unique number to identify each seedling. 2. Water treatment: treatment category indicating the water volume (in mililiters) per watering event. No water: 0 mililiters; Low water: 70 mililiters; medium water: 281 ml; high water 563 mililiters 3. Light: this column refers to the light treatment under which the seedlings were grown. The light intensities were measured in terms of photosynthetic photon flux (PPF) and were the following: full light 970 μmol m^−2 s^−1; medium light 120 μmol m^−2 s^−1; low light 9 μmol m^−2 s^−1.  4. Height_final: total height of each sapling in centimiters, measured from the root collar to the apical meristem at the end of the experiment, previous to harvesting the plants. 5. Diameter_final: diameter of the stem in milimiters, measured at the root collar 6. Fresh leaves mass: Total mass of the leaves (in grams) weighed inmediately after harvesting 7. Dry leaves mass: Total mass of the leaves (in grams) weighed after the seedlings were oven dried for at least 48 hours, or untill they achieved a constant weight. 8. Fresh stem mass: Total mass of the stem (in grams) weighed inmediately after harvesting 9. Dry stem mass: Total mass of the stem (in grams) weighed after the seedlings were oven dried for at least 48 hours, or untill they achieved a constant weight. 10. Fresh root mass: Total mass of the root (in grams) weighed inmediately after harvesting 11. Dry root mass: Total mass of the root (in grams) weighed after the seedlings were oven dried for at least 48 hours, or untill they achieved a constant weight. 12. total_aboveground_mass: total mass of the aboveground structures of the seedling (in grams). Obtained by adding dry leaves and dry stem mass 13. DRY_WHOLE_PLANT_BIOMASS: total mass of the sapling after drying (in grams). It is the sum of the dry mass of the leaves, root and stem. 14. SMF: Stem mass fraction: This metric represents the proportion of a plant's total dry biomass that is attributable to the stem. It is calculated by dividing the dry weight of the stem by the total dry biomass of the plant. 15. LMF: Leaf mass fraction: This metric represents the proportion of a plant's total dry biomass that is attributable to the leaves. It is calculated by dividing the dry weight of the leaves by the total dry biomass of the plant. 16. RMF: Root mass fraction: This metric represents the proportion of a plant's total dry biomass that is attributable to the root. It is calculated by dividing the dry weight of the root by the total dry biomass of the plant. 17. RSR: Root to shoot ratio: Calculated by dividing the total root dry mass by the total aboveground biomass. 18. Stomatal density: Stomatal density refers to the number of stomata (pores) per unit area on the surface of leaves. Measured as the count of stomata per square millimeter (stomata per mm²). Cells with NA indicate no values, because this parameter was not measured or calculated for those plants.  19. FvFm: Fv/Fm, or the maximum quantum efficiency of Photosystem II, is a ratio derived from chlorophyll fluorescence measurements. It is calculated using the formula Fv/Fm=(Fm−Fo)/FmFv/Fm = (Fm - Fo)/FmFv/Fm=(Fm−Fo)/Fm, where FmFmFm (maximum fluorescence) and FoFoFo (minimum fluorescence). Cells with NA indicate no values, because this parameter was not measured or calculated for those plants.  #### File: Tamarind\_saplings\_growth.xlsx All the data are contained in columns/rows and each row represents an individual tamarind sapling.  The following is a description of the columns: 1. Individual: a unique number to identify each sapling. 2. Water treatment:  treatment category indicating the water volume (in mililiters) per watering event. No water: 0 mililiters; Low water: 70 mililiters; medium water: 281 ml; high water 563 mililiters; once week: seedlings were watered with 281 ml but water was administered only once a week; biweekly: seedlings were watered with 281 ml but water was administered only once every two weeks 3. final height: total height of each sapling in centimiters, measured from the root collar to the apical meristem at the end of the experiment, previous to harvesting the plants. 4. final Diameter: diameter of the stem in milimiters, measured at the root collar 5. Fresh leaves mass: Total mass of the leaves (in grams) weighed inmediately after harvesting 6. Fresh root mass: Total mass of the root (in grams) weighed inmediately after harvesting 7. Fresh stem mass: Total mass of the stem (in grams) weighed inmediately after harvesting 8. Dry leaves mass: Total mass of the leaves (in grams) weighed after the seedlings were oven dried for at least 48 hours, or untill they achieved a constant weight. 9. Dry stem mass: Total mass of the stem (in grams) weighed after the seedlings were oven dried for at least 48 hours, or untill they achieved a constant weight. 10. Dry root mass: Total mass of the root (in grams) weighed after the seedlings were oven dried for at least 48 hours, or untill they achieved a constant weight. 11. Total_aboveground_biomass:  total mass of the aboveground structures of the seedling (in grams). Obtained by adding dry leaves and dry stem mass 12. Total_Dry: total mass of the sapling after drying (in grams). It is the sum of the dry mass of the leaves, root and stem. 13. LMF: Leaf mass fraction: This metric represents the proportion of a plant's total dry biomass that is attributable to the leaves. It is calculated by dividing the dry weight of the leaves by the total dry biomass of the plant.  14. SMF: Stem mass fraction: This metric represents the proportion of a plant's total dry biomass that is attributable to the stem. It is calculated by dividing the dry weight of the stem by the total dry biomass of the plant. 15. RMF: Root mass fraction: This metric represents the proportion of a plant's total dry biomass that is attributable to the root. It is calculated by dividing the dry weight of the root by the total dry biomass of the plant. 16. RSR: Root to shoot ratio: Calculated by dividing the total root dry mass by the total aboveground biomass. ## Access information This is original data derived from experiments in a greenhouse at the University of Minnesota.