Ecophysiological responses to drought and salinity in the cosmopolitan invader Nicotiana glauca

Abstract

Nicotiana glauca, a shrub native to southern South America, is widely distributed in the Americas, from Patagonia to the USA, from zero up to 3,700 m; it rapidly invades disturbed environments. In Venezuela, it has been reported from zero up to 2,000 m growing in contrasting conditions of relative humidity, temperature, rainfall, and salinity. In order to gain insight into the extent and mode of resistance to drought and salinity in N. glauca, we studied the effect of these factors on water relations and photosynthesis under both natural and greenhouse conditions. In the field, water potential, photosynthetic rate (A) and stomatal conductance (g s ), but not relative water content (RWC) decreased because of drought. Manual removal of epicuticular wax increased excess energy dissipation through non-photochemical quenching without altering the capacity of photochemical quenching. In the greenhouse, water deficit as well as salinity resulted in osmotic adjustment; at the end of the experiment, turgor potential and RWC under water deficit were similar to control and higher under salinity. Water deficit and salinity caused marked decreases in A and g s . There were very few or no changes with natural drought, salinity or experimental water deficit in potential quantum efficiency of PSII, which could be explained partly by an increased nonphotochemical quenching. We conclude that the partial tolerance to drought and salinity in plants of N. glauca resides in their ability to achieve water conservation through stomatal closure and osmotic adjustment, reduce absorption of excess radiation through the presence of leaf wax and dissipate it through increased non-photochemical quenching. All these characteristics confer plants of N. glauca advantages to invade disturbed areas, subject to salinity and/or seasonal drought under high irradiance.

Automatically controlled deficit irrigation of lettuce in “organic potponics”

“…The RWC maintenance associated with gs reduction and osmotic adjustment was reported for Nicotiana glauca (Gonzáles et al, 2012). The high values of RWC exhibited in plants with low irrigation volumes here could also be due to the osmotic adjustment, which has been reported for lettuce (Lucini et al, 2015).…”

The genome and metabolome of the tobacco tree, Nicotiana glauca: a potential renewable feedstock for the bioeconomy

“…Tree tobacco ( Nicotiana glauca ) is a wild tobacco species, not only endemic to South America but also widespread as an introduced, invasive species in other continents, that exhibits partial drought and salinity tolerance under high irradiance [1]. N. glauca grows in arid environments [1], usually not suitable for food crops, and has vast potential as a biofuel stock due to an exceptionally high content of hydrocarbons [2]. In addition, N. glauca has been discussed for medicinal purposes due to its rich content in metabolites such as scopoletin [3].…”

Salinity induction of recycling Crassulacean acid metabolism and salt tolerance in plants of Talinum triangulare

“…Osmotic adjustment is a mechanism which some plants employ to reduce osmotic potential (ψ s ) and increase turgor potential against water deficit conditions, including salinity (Munns and Tester, 2008). Osmotic adjustment has been shown to occur under salinity in many glycophytes, such as Nicotiana glauca, which are not usually subjected to saline soils (González et al, 2012).…”