Effects of Copper on Nitrogen Assimilation in Copper-tolerant and Non-tolerant Populations of Elsholtzia haichowensis S.

Abstract

Two Elsholtzia haichowensis S. populations, copper-tolerant (TLS) and non-tolerant (HA) ones were studied in hydroponic experiment for the nitrogen assimilation and plant growth under excess Cu conditions. The results demonstrated that there were surely the differences in nitrogen assimilation and plant growth between the two populations. Excess Cu caused evident decreases in the shoot and root biomass and root/shoot biomass ratio in HA population while no significant changes happened in TLS population. In addition, in HA population, excess Cu also induced apparent declines in activities of nitrate reductase (NR, EC 1.6.6.1) and glutamine synthetase (GS, EC 6.3.1.2) in the leaves and roots as well as the contents of nitrate, ammonium and amino acids in the roots. In TLS population, excess Cu did not significantly affect the NR activities in the leaves and roots and the nitrate content in the roots, and apparently elevated the root ammonium and amino acids contents, although it also clearly reduced the GS activities in the leaves and roots. Besides, with the addition of Cu in the culture solution, the Cu contents in the leaves and roots of the two populations markedly increased. But this increase was significantly lower in TLS population than that in HA population; the fact might be partly responsible for the relative stabilization of nitrogen assimilation in TLS population compared to that in HA population.

Differential response to copper stress in the reproductive resources and allocation of metallophyte Kummerowia stipulacea

“…The results show that the plants in metallicolous population reduce the transfer of Cu from roots to stems and leaves. Similar results were also observed in Rumex japonicas (Ke et al, 2007a), Rumex dentatus (Liu et al, 2004) and Elsholtzia haichowensis (Liu and Xiong, 2005;Li et al, 2007). In our experiments, the quantity of Cu transferred from roots to stems and leaves in the metallicolous population is only about 63-75% of that of the non-metallicolous population with Cu exposure (Fig.…”

“…As a result, Cu concentration of the soil in this area is considerably elevated, and plants there have developed into metallophyte vegetation. Several Cu tolerant plant species are identified in this contaminated area (e.g., Liu et al, 2004;Liu and Xiong, 2005;Ke et al, 2007a,b;Li et al, 2007), among which is Kummerowia stipulacea (Xiong et al, 2008). K. stipulacea is a dominant species in the metallophyte vegetation of this area.…”

Antioxidative defense mechanism of the ruderal Verbascum olympicum Boiss. against copper (Cu)-induced stress

“…These alterations are related to nitrogen assimilation and also to the inhibition of enzymes involved in protein synthesis in Verbascum olympicum [14]. Similar results have been observed in Cu-tolerant E. haichowensis [36] and also in both tolerant and sensitive species of Silene vulgaris [37]. roots and leaves of seedlings depending on both the Cu concentration and duration of exposure (P < 0.05).…”

Biostimulant activity of silicon in horticulture

“…Indeed, a less severe inhibition of net photosynthesis by salinity in plants treated with Si in comparison with plants exposed to the same salinity level without Si supply, has been reported for several horticultural plants, including bean (Zuccarini, 2008), cucumber , maize (Li et al, 2007), tomato (Romero-Aranda et al, 2006), and zucchini squash (Savvas et al, 2009). As reported by Savvas et al (2009), Si-mediated amelioration of the adverse salinity levels on plant biomass production in zucchini squash was related to commensurate protection of net CO 2 assimilation rates by Si (Fig.…”