poster - International Conference of Agricultural Engineering

TABLE 2: Summary of variance analysis and averages for levels of sodium in the roots,
rootstock, graft, branches and leaves of the dwarf cashew tree CCP76 clone irrigated with
different salt concentrations water, after 90 days of salt stress.
Branche
s
Sources of
Roots Rootstock Graft
Leaves
GL
Variation
Mean Square
Salinity 4 1,29** 0,934** 0,51** 0,59** 0,3725 ns
Linear
1 1,18** 3,679** 1,40** 1,56** 0,0003 ns
Regression
Quadratic
1 3,66** 0,051 n s 0,07 ns 0,61* 1,1389 ns
regression
Desviation 2 0,15 ns 0,004 ns 0,28** 0,09 ns 0,1753 ns
Block 5 0,03 ns 0,051 ns 0,10 ns 0,19 ns 0,0511 ns
Residue 20 0,10 0,157 0,05 0,11 0,1361
CV (%) 12,65 14,46 8,74 11,86 8,40
Averages of the sodium content
(dS m -1 ) mg kg -1
S 1 (0,8) 2,58 3,81 3,68 4,49 15,66
S 2 (1,6) 5,00 5,36 4,47 6,85 21,18
S 3 (2,4) 8,67 7,00 5,50 8,83 19,37
S 4 (3,2) 7,33 8,14 4,61 7,91 19,22
S 5 (4,0) 4,73 9,41 7,53 8,60 16,71
As the same case of chloride, with the increasing of the sodium salinity of the water is mainly
due to the fact that the water were prepared with sodium chloride, and well as increased the
amount of sodium in the irrigation water, the increased amount of sodium added to the soil
and consequently the plant. In the case of cashew tree leaves allegedly directed sodium to
the old leaves (with low metabolic activity) as reported by Shannon et al. (1994) for some
species tolerant to salinity. According to Marschner (1995) would be a restriction on imports
of sodium and chloride to the young leaves, which is a characteristic of salinity tolerant
species.
The regression analysis of the variation of sodium content in different parts of the plant by
increasing the salinity of the water irrigation and their equations are shown in Figure 1. For
the content of Na in roots and branches, there was a statistically significant quadratic effect
(p