The effects of irrigation periods and soil texture on fruits number, vascular transport defect of ovule (seed) and fruits blankness in two pistachio (Pistacia vera L.) cultivars

The vascular system allows plants to rapidly transport water and nutrients over long distances between roots and other plant parts. It also provides mechanical support for the plant body. In this study, the effect of soil texture (light and heavy) and irrigation periods (24 and 48 days) were assayed on vascular transport defect of ovules and fruits blankness in two pistachio cultivars (Kalehghoochi and Ahmadaghae). Eight weeks after flowering, some branches were kept in disodium fluorescein solution. Then, the small fruits were sectioned by hand and studied with fluorescence microscopy for vascular defect. The rate of fruit blankness was determined at harvest time too. Overall levels of developed ovules (fruits) in each inflorescence as well as fruit blankness were studied. The fruits numbers were higher in shorter irrigation period (24 days) and heavy soil compared with longer irrigation period (48 days) and light soil. Also, the rate of vascular transport defect in ovules as well as fruit blankness were higher too. These results can be attributed to the higher number of fruits produced in high water availability and heavy soil, as optimal condition, and in results, their stronger competition for fruit filling. It was also shown that in comparison with Ahmadaghaee cultivar, the Kaleghoochi cultivar mostly through the vascular transport blocking in developing ovules (seeds) is resulted in blankness of fruits. Vascular transport defects can occur transiently and be repaired by the plant.