Anatomical Changes in Various Fruit Trees Roots under Different Soil Water Conditions – A Review

Understanding that abiotic stress conditions stimulate changes in root tissues is important to know its function. Under drought or flooded conditions, woody roots of perennial fruit tree roots undergo anatomical changes during primary and secondary growth. So far, anatomical studies have been conducted on some fruit trees. However, such changes vary according to the plant family. This review highlights the changes in root tissue development in Rosaceae, Myrtaceae, Punicaceae and Vitaceae. We reviewed anatomical studies conducted in loquat (Eriobotrya), apple (Malus), peach (Prunus) and pear (Pyrus) belonging to Rosaceae; feijoa (Feijoa sellowiana), waxapple (Syzygium samarangense), rose apple strawberry guava (Syzygium jambos), and guava (Psidium cattleianum Sabine) belonging to Myrtaceae; pomegranate (Punica granatum) belonging to Punicaceae and grapes (Vitis) belonging to Vitaceae. It is important to note that biopolymer accumulation in cell wall of various root tissues differ during primary and secondary root growth in fruit tree roots. In the time span of anatomical research, many names were given to different thickenings in the cell wall of root tissues according to how it was observed under the microscope. Phi-thickenings were observed only in Rosaceae, biopolymer accumulation in polyderm was typical of Myrtaceae and brick-like accumulation in the periderm was unique to Punicaeae and suberin-like accumulation was observed in Vitaceae. It is important to note two findings when considering woody fruit tree roots growing under different soil water conditions. Firstly, the root tissue where the biopolymer accumulation occurs varies according to growth stage and secondly, it varies according to plant family. Knowing about biopolymer accumulation in fruit tree roots is important for fruit tree rootstock breeding.