Effects of green seaweed extract onArabidopsisearly development suggest roles for hormone signalling in plant responses to algal fertilisers

Abstract

The growing population requires sustainable, environmentally-friendly crops. The plant growthenhancing properties of algal extracts have suggested their use as biofertilisers. The mechanism(s) by which algal extracts affect plant growth are unknown.We examined the effects of extracts from the common green seaweed Ulva intestinalis on germination and root development in the model land plant Arabidopsis thaliana. Ulva extract concentrations above 0.1% inhibited Arabidopsis germination and root growth. Ulva extract <0.1% stimulated root growth. All concentrations of Ulva extract inhibited lateral root formation.An abscisic-acid-insensitive mutant, abi1, showed altered sensitivity to germination-and root growth-inhibition inhibition. Ethylene-and cytokinin-insensitive mutants were partly insensitive to germination-inhibition. This suggests that different mechanisms mediate each effect of Ulva extract on early Arabidopsis development and that multiple hormones contribute to germinationinhibition.Elemental analysis showed that Ulva contains high levels of Aluminium ions (Al 3+ ). Ethylene and cytokinin have been suggested to function in Al 3+ -mediated root growth inhibition: our data suggest that if Ulva Al 3+ levels inhibit root growth, this is via a novel mechanism. We suggest

Germination of soybean seeds exposed to the static/alternating magnetic field and algal extract

“…The nutrient analysis of freshwater macroalga showed the presence of macroelements, Ca, K, Mg and Na, as well as microelements such as Cu, Mn, Zn, etc. This content was much higher than for other green seaweed, for example, Ulva lactuca , collected from the coastal area of Jalisco, Mexico (Na 77.7 mg/kg, K 18.5 mg/kg, Ca 18.8 mg/kg, and P 1 mg/kg) and for Ulva intestinalis from the coastal area of Llantwit Major beach, South Wales, where the content of Ca was 37 046 mg/kg and of K 16 466 mg/kg . The content of Mg and Na in Ulva intestinalis in the work of Ghaderiardakani et al.…”

“…The content of Mg and Na in Ulva intestinalis in the work of Ghaderiardakani et al. (2019) was much higher (Mg 14 291 mg/kg and Na 61 861 mg/kg; these two elements dominate in the composition of marine water) than for the tested freshwater C. glomerata . Freshwater macroalga can be recommended as a raw material for the production of biostimulants of plant growth.…”

“…Freshwater macroalga can be recommended as a raw material for the production of biostimulants of plant growth. The differences in the elemental composition of macroalgae can result from different locations of their harvesting, different climatic conditions, as well as different analytical techniques, for example, atomic absorption spectrophotometry [63] and inductively coupled plasma-MS [64] used for determination of the composition. The relation and the multielemental composition of the raw algal biomass and the produced extract are randomly studied in the literature.…”

“…In ref. [64], it was shown that Ulva extract concentrations above 0.1% inhibited germination and root growth of the model land plant (Arabidopsis thaliana). Taking into account wide ranges of applied algal extracts, a special attention should be paid to plant species, for which these extracts are designed.…”

Screening of microalgae liquid extracts for their bio stimulant properties on plant growth, nutrient uptake and metabolite profile of Solanum lycopersicum L.

“…Sugars for instance act both as effective signalling molecules and as immediate substrates for intermediary metabolism, and could therefore promote plant growth and development 20,23 . A role for macro-and microelements, vitamins and phytohormones in alga extracts may also be suggested 11,12,20,24 . For instance 16 , reported that Potassium in seaweed extracts have a positive effect on regulating water status in treated plants and enhancing photosynthesis and meristematic growth.…”