Abstract

MIRANDA, Diego; ULRICHS, Christian  and  FISCHER, Gerhard. Dry matter accumulation and foliar K, Ca and Na contents in salt-stressed cape gooseberry (Physalis peruviana L.) plants. Agron. colomb. [online]. 2010, vol.28, n.2, pp.165-172. ISSN 0120-9965.

A pot experiment aimed at determining the effect of five NaCl concentrations (namely 0, 30, 60, 90 and 120 mM, determining respective EC values of 0.8, 3.0, 6.0, 9.0 and 12.2 dS m^-1) on cape gooseberry plants was set up at Humboldt University's greenhouse in Berlin, Germany. Dry weight (DW) of roots, stems and leaves, as well as foliar content of ions K⁺, Ca²⁺ and Na⁺ and the relationship they hold with one another, were determined over a 75-day period. DW of all plant organs was observed to decrease with increasing salinity. The lowest values of this variable, which were recorded from the 120 mM NaCl plants, were found to be significantly smaller than those recorded at 60 mM and lower salt concentrations. Salt stress effects on dry matter (DM) accumulat ion were observed to increase with plant age. Leaf K⁺ content increased with salinity and peaked at 90 mM NaCl, where the value was significantly higher than that observed at 120 mM. Foliar Ca²⁺ content remained unchanged at the different salt concentrations, whilst Na⁺ content increased together with salt stress. The relationship among ion concentrations was significantly influenced only by 90 mM or higher NaCl concentrations, which determined a progressive increase of the Na⁺/Ca²⁺ ratio and a similar decrease of the K⁺/Na⁺ ratio. According to the results, cape gooseberry can be considered as moderately tolerant to salt, as shown by the 30 mM NaCl treatment, which did not affect DM accumulation in plant organs. This tolerance is also supported by steady leaf Ca²⁺ contents at all levels of salinity, indicating that cape gooseberry uses K⁺ as an osmoprotectant, at least up to 90 mM NaCl.

Keywords : dry weight; Na⁺/Ca²⁺ ratio; K⁺/Na⁺ ratio; salt-tolerant; osmoprotectant.

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