Browse Publications Technical Papers 1999-01-2020
1999-07-12

Water Relations and Leaf Gas Exchange of Table-Beet in Response to Replacement of Nutrient K with Na 1999-01-2020

Developing crop-based approaches for sodium recycling may be required for integrating urine and gray water into food production systems for advanced life support. Sodium (Na) is generally considered non-essential for plants, whereas potassium (K) is a macro-nutrient involved in a range of metabolic functions, including maintenance of cell turgor and water relations. This study compared if K can be largely replaced with Na in the nutrient solutions without affecting productivity. Table-beet (Beta vulgaris) variety Ruby Queen was grown at K/Na (mM) ratios of 5.0/0, and 0.1/4.90 (represents 0% and 98% substitution of K with Na in nutrient solutions) in a re-circulating hydroponic system. Plants were grown at elevated CO2 (i.e. at 1200 μmol mol−1) in growth chamber for 42 days. Leaf photosynthetic rates were measured at 32 days after planting. Leaf relative water content (RWC) and osmotic potential were measured at harvest. Replacing nutrient K with Na had no significant effect on leaf chlorophyll levels or photosynthetic rate. Leaf relative water content was significantly higher at K/Na 0.1/4.90 than 5.0/0 treatment. Osmotic potential of the leaf sap was not significantly affected by Na substitution for K. Sodium concentrations reached to about 300 mM in leaf sap. Results indicated that table-beet has a high degree of tolerance to substitution of tissue K with Na. We conclude that for table beet, K could be managed as a micro-nutrient in the presence of adequate sodium which could take over some of the osmotic functions of K.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 43% off list price.
Login to see discount.
Special Offer: With TechSelect, you decide what SAE Technical Papers you need, when you need them, and how much you want to pay.
X