Alfonso Llanderal

Effects of Salinity on Growth, Water-Use Efficiency, and Nutrient Leaching of Three Containerized Ornamental Plants

ABSTRACT The scarcity of water in the Mediterranean area has frequently led to the use of saline water to irrigate ornamental plants in nurseries. Aloe vera L. Burm, Kalanchoe blossfeldiana Poelln, and Gazania splendens Lem. plants were grown in a greenhouse from the University of Almeria in containers with a mixture of sphagnum peat moss and perlite in order to evaluate the effect of salinity levels on plant growth, water-use efficiency, and nutrient leaching. The experimental design consisted of three salinity treatments, four blocks, and four plants (one plant per container) per treatment-block giving a total of 12 plants per species plus border plants placed around the perimeter of the treatment plants to maintain uniform growing conditions for treatment plants. At the end of the experiment, plant dry weight and water-use efficiency were assessed for each salinity treatment. Leachate was collected weekly and analyzed for concentrations of nitrate-nitrogen, phosphate-phosphorus, potassium, calcium, and magnesium (NO3–N, PO43–P, K+, Ca2+ and Mg2+). Increasing salinity levels of irrigation water reduced the plant dry weight in all species and affected the leachates volume and their nutrients concentrations. We suggest the use of low salinity levels in water to improve the growth and to reduce the environmental impacts of nutrient runoff.

Nutritional and physiological responses of the dicotyledonous halophyte Sarcocornia fruticosa to salinity

Sarcocornia fruticosa (L.) A.J. Scott is a dicotyledonous halophyte that grows in areas with an arid climate such as the marshes of southern Spain. The species has potential uses for saline agriculture and biofuel production, but the effects of salt stress on its nutrition and physiology remain unclear. Plants of S. fruticosa were grown in pots with a mixture of sphagnum peat-moss and Perlite. In order to evaluate the effects of different levels of salinity, five treatments using different NaCl concentrations (10 (control), 60, 100, 200 and 300 mM NaCl) were applied over a period of 60 days. At the end of the experiment, the dry weight, the biomass allocation and the tissue water content were measured for each salinity treatment. The net uptake of various nutrients and their translocation rates were calculated for each salt treatment. Salt loss, shedding of plant parts and succulence in shoots were evaluated together with the K+/Na+ ratio, K-Na selectivity, concentrations of osmolytes and their estimated contributions to the osmotic potential. Our results showed that S. fruticosa can maintain its major physiological processes at 60 mM NaCl without significant dry weight reduction. Higher salinity resulted in negative values for net uptake and translocation rates from roots to shoots of N and P. As might be predicted from other dicotyledonous halophytes, S. fruticosa plants increased Cl– and Na+ uptake using both as osmotica instead of organic osmolytes. However, to survive salinity, this species has also evolved others mechanisms such as shedding old shoots, increased succulence in shoots at higher salt concentrations and the ability to maintain a lower K+/Na+ ratio and higher K-Na selectivity in all organs.

Water and Nutrient Uptake Efficiency in Containerized Production of Fern Leaf Lavender Irrigated with Saline Water

The scarcity of water in the Mediterranean area has frequently led to the use of saline water for irrigation. Container grown ornamental production has relatively high rates of water and nutrient loss from fertigation. A better understanding of water and nutrient use efficiency with water that has elevated levels of saline could reduce runoff water and its environmental impact. Fern leaf lavender (Lavandula multifida) plants were grown for 8 weeks in plastic containers with a sphagnum peatmoss and perlite substrate (80:20 by volume) to evaluate the effect of saline water [2.0 (T1 or control), 4.5 (T2), or 7.5 (T3) dS m] on water and nutrient uptake efficiency. Leachate was collected to determine runoff volume and composition which included nitrate-nitrogen (NO3 -N), phosphate-phosphorus (PO4 -P), and potassium (K) concentration. Plant dryweight (DW) and nutrient content were determined in plants at the beginning and at the end of the experiment to establish the nutrient balance. Increasing salinity levels of irrigation water did not significantly reduce either the plant DW or the water use efficiency (WUE). Based on nutrient balance, the increasing salinity (2.0 to 7.5 dS m) affected the plant nutrient uptake efficiency, which decreased 28% for N, increased 26% for P from the lowest to highest sodium chloride levels; whereas K did not show a clear trend. Nutrient runoff increased (28% N, 9% P, and 27% K) to the environment from the lowest to highest sodium chloride levels.

Evaluation of the Nutrients Variability in Sap of Different Petiole Samples in Tomato Plant

ABSTRACT The aim of this trial was to study the variability of anions and cations concentrations in the different petiole samples: young leaves (YL), mature leaves (ML) and aged leaves (AL). The experimental design consisted of four blocks and four plants per block being each plant one replication. In each plant, petiole samples were collected at 135 days after transplanting (DAT) to determine chloride, nitrate-nitrogen, phosphate-phosphorus, sulfate-sulfur, sodium, potassium, calcium, and magnesium (Cl−, NO3–N, H2PO4–P, SO42–S, Na+, K+, Ca2+ and Mg2+) concentrations. Our results showed that the selection of sample petiole in the tomato crop did not modify the Ca2+, Cl−, SO42–S and Na+ concentrations, while NO3–N, K+, Mg2+ and H2PO4–P concentrations showed a great variability due to the selection of the sample petiole, therefore it is necessary to be careful with the sample selection.

Response of Container-grown Confetti Tree Irrigated with Runoff Water

This experiment measured plant growth of a halophyte (species adapted to saline conditions) confetti tree (Maytenus senegalensis) using runoff from kneeholy plants (Ruscus aculeatus). Three irrigation treatments were used, a standard nutrient solution or control (T0), runoff water collected from kneeholy plants irrigated with the standard nutrient solution blended 50:50 with tap water (T1), and 100% runoff water collected from kneeholy plants irrigated with the standard nutrient solution (T2), in which the nutrient concentrations were analyZed by highperformance liquid chromatography. Growth, photosynthetic parameters, and mineral composition were measured at the end of the experiment. Electrical conductivity and pH increased with increasing runoff application (decreased blending). Treatment 2 had significantly higher plant height, number of branches, number of leaves, leaf area index, and dry weight. Treatments 1 and 2 had significantly lower root lengths compared with the control. Chlorophyll concentration and green index color in leaves were greater in T2 and T1 than T0. The mineral composition of roots and leaves was affected by irrigation treatment, resulting in an increase of sodium and chloride concentration and a decline of nitrogen and phosphorous concentration compared with the control. The reuse of runoff water was beneficial for growing this commercially important halophytic species in Spain, a consideration that is particularly relevant in locations with water quality, quantity issues, or both.

Sodium Chloride Effects on Water and Nutrient Uptake Efficiency in Sarcocornia fruticosa Containerized Production

ABSTRACT The ability to produce native plants well adapted to the saline conditions without the production of nutrient-rich runoff will be a boon to nurseries hoping to reduce their environmental contamination impact and water use while at the same time producing quality plants to be used in the restoration of saline lands. Sarcocornia fruticosa plants were grown for 8 weeks in plastic containers with a source of sphagnum peat moss and perlite (80:20 v/v) to evaluate the effect of two salinity levels (2.0 (low-salinity treatment) and 7.5 dS m−1 (high-salinity treatment)) on plant growth, nutrient concentration in leachate and water and nutrient uptake efficiency and their losses. Leachate was collected to determine the runoff volume and composition, which included nitrate-nitrogen (NO3–N), phosphate-phosphorus (PO43–P) and potassium (K+) concentrations. Plant dry weight (DW) and nutrient content were determined in plants at the beginning and at the end of the experiment to establish the nutrient balance. Increasing salinity levels of irrigation water did not reduce either the plant DW or the water-use efficiency (WUE), but increased the volume of leachate per plant. The nutrient concentrations in leachates without significant differences between salt treatments exceeded the thresholds established by environmental guidelines, leading to a great risk of pollution. Based on nutrient balance, the irrigation with a higher salinity level reduced the plant nutrient uptake efficiency (10%, 18% and 12% for nitrogen (N), phosphorus (P) and potassium (K), respectively) and increased the nutrient losses (6% N, 7% P and 8% K), resulting in the recommendation to grow this species with the low salinity level based on the highest nutrient-use efficiency and the lowest levels of nutrient losses.