The role of biostimulants and bioeffectors as alleviators of abiotic stress in crop plants

Abstract

The use of bioeffectors, formally known as plant biostimulants, has become common practice in agriculture and provides a number of benefits in stimulating growth and protecting against stress. A biostimulant is loosely defined as an organic material and/or microorganism that is applied to enhance nutrient uptake, stimulate growth, enhance stress tolerance or crop quality. This review is intended to provide a broad overview of known effects of biostimulants and their ability to improve tolerance to abiotic stresses. Inoculation or application of extracts from algae or other plants have beneficial effects on growth and stress adaptation. Algal extracts, protein hydrolysates, humic and fulvic acids, and other compounded mixtures have properties beyond basic nutrition, often enhancing growth and stress tolerance. Non-pathogenic bacteria capable of colonizing roots and the rhizosphere also have a number of positive effects. These effects include higher yield, enhanced nutrient uptake and utilization, increased photosynthetic activity, and resistance to both biotic and abiotic stresses. While most biostimulants have numerous and diverse effects on plant growth, this review focuses on the bioprotective effects against abiotic stress. Agricultural biostimulants may contribute to make agriculture more sustainable and resilient and offer an alternative to synthetic protectants which have increasingly falling out of favour with consumers. An extensive review of the literature shows a clear role for a diverse number of biostimulants that have protective effects against abiotic stress but also reveals the urgent need to address the underlying mechanisms responsible for these effects.

Pengaruh biostimulan terhadap toleransi kekeringan dan pertumbuhan tanaman tebu varietas Kidang Kencana di rumah kaca (Effect of biostimulants on drought tolerance and growth of sugarcane var. Kidang Kencana at green house)

“…Teknologi biostimulan tanaman telah banyak diaplikasikan untuk meningkatkan produktivitas tanaman semusim (Santoso & Priyono, 2014;Rouphael et al, 2017), namun teknologi tersebut belum banyak diterapkan pada tanaman tebu, khususnya varietas Kidang Kencana. Biostimulan merupakan bahan yang mengandung zat dan/atau mikroorganisme yang memiliki efek positif terhadap pertumbuhan tanaman serta memiliki fungsi sebagai perangsang serapan hara dan nutrisi secara alami, mengefisienkan penggunaan nutrisi serta meningkatkan toleran terhadap stress abiotik dan biotik (Sharma et al, 2016;Oosten et al, 2017). Kategori biostimulan berdasarkan pemahaman secara umum di antaranya ekstrak rumput laut, silika, kitosan, asam humat dan fulvat, mikoriza, trichorderma, dan hidrolisat protein (Oosten et al, 2017).…”

“…Biostimulan merupakan bahan yang mengandung zat dan/atau mikroorganisme yang memiliki efek positif terhadap pertumbuhan tanaman serta memiliki fungsi sebagai perangsang serapan hara dan nutrisi secara alami, mengefisienkan penggunaan nutrisi serta meningkatkan toleran terhadap stress abiotik dan biotik (Sharma et al, 2016;Oosten et al, 2017). Kategori biostimulan berdasarkan pemahaman secara umum di antaranya ekstrak rumput laut, silika, kitosan, asam humat dan fulvat, mikoriza, trichorderma, dan hidrolisat protein (Oosten et al, 2017). Chen et al (2018) melaporkan penggunaan biostimulan berbasis ekstrak rumput laut dapat meningkatkan kandungan air relatif, tinggi tanaman, biomassa, hijau daun tanaman tebu dalam kondisi cekaman kekeringan.…”

Influence of Acacia dealbata Link bark extracts on the growth of Allium cepa L. plants under high salinity conditions

“…Because of the multicomponent composition, the effect of biostimulants may be influenced by the geographical location, plant growing conditions, season, species, organ, and phenological stage, with their mode of action still unknown/unpredictable . Biostimulants include microbial inoculants, humic acids, fulvic acid hydrolysates of proteins, amino acids, or seaweed extracts, among others . Biostimulants have been proven to promote plant growth, and they were particularly relevant to the development of the stress tolerance of crops under unfavorable conditions .…”

“…or Spinacia oleracea L . Biostimulants were also effective at cold temperatures or under heat‐stress conditions …”

Evaluation of antioxidant activity and total phenol content of Gracilaria bursa-pastoris harvested in Nador lagoon for an enhanced economic valorization

“…Since the year 2000, the seaweeds have attracted attention in the search for bioactive compounds to develop new drugs and healthy foods [1,2]. In particular, these organic resources are a very important and commercially valuable resource for food, fodder, soil conditioners, pharmaceuticals, and production of green energy [3,4].…”