by inadequate condition of plants during the critical
phenophases.
In the last decade, a great number of products
known as biostimulants that are applied to crops
appeared on the market (Boehme et al. 2004). Substances
with biological origin have been used to
avoid or counteract abiotic or biotic stress in horticulture.
Many of these materials are natural products
without chemicals or plant growth regulators
(Russo, Berlyn 1991), and according to Crouch
et al. (1992) can be classified into three major
groups on the basis of their source and content: humic
substances, hormone containing products and
amino-acid containing product. The third group of
biostimulants consists of mixtures of peptides and
free amino acids which can be obtained by chemical
and/or enzymatic hydrolysis of an organic matrix
of plant or animal origin and their composition
can be highly variable (Maini 2006). Biostimulants
usage has become a common practice in sustainable
agriculture, because their application reduces
fertilizers and other chemical compound application
in agriculture (Russo, Berlyn 1991). Some
studies already investigated positive effects of biostimulants
on plants. These studies mostly investigated
biostimulant influence on plant growing,
rooting, biomass of newly formed roots, early flowering
and fruiting (Marfa et al. 2008) and thermal
stress (Polo et al. 2006), but there is a small number
of those that had experiments including ecological
conditions of continental Croatia.
The main focus of this paper relies on the biostimulant
containing amino-acids of animal origin (porcine
blood). The effects of biostimulator on strawberry