[82,84], green beans [55,57,58,94,95], alfalfa [56], and eggplant, Solanum melongenaL. [60]. Such dif-
ferences reflect variations in the salt tolerance of these different plant types. The high level of salinity
(1.2 MPa) appears to have caused a substantial reduction in the N absorption rate of cotton plants. The
effect of the high salinity level on^15 N uptake was more pronounced at the vegetative stage than at the re-
productive stage of growth. The values for^15 N uptake obtained by total N analysis of the plant materials
(Tables 2 and 3) indicated essentially the same pattern as the solution loss data (Figures 1 and 2). Total
amounts of^15 N recovered in plants generally accounted for 95 to 99% of the apparent solution loss.
686 PESSARAKLI
Figure 2 Solution loss of^15 N (uptake) by cotton plants under various NaCl salinity conditions at the begin-
ning of the reproductive stage of growth. (From Ref. 62.)
TABLE 2 Distribution of^15 N Absorbed as Ammonium in Cotton Shoots and Roots Under Different
NaCl Salinity Levels During Vegetative Stage of Growth
(^15) N uptake/pot (two plants) (mg)
Treatment, osmotic potential Uptake time, hr
Plant parts (MPa) 6 12 24
Shoots Control 0.98 1.61 4.97
0.4 0.82 1.71 4.78
0.8 1.02 1.63 4.36
1.2 0.36 0.88 1.81
LSD (.05)a 0.43 0.49 0.45
Roots Control 0.73 1.29 3.22
0.4 1.39 1.84 4.20
0.8 0.67 1.27 3.23
1.2 0.34 0.57 1.24
LSD (.05)a 0.48 0.93 0.77
Total Control 1.71 2.90 8.19
0.4 2.21 3.55 8.98
0.8 1.69 2.90 7.59
1.2 0.70 1.45 3.05
LSD (.05)a 0.32 0.95 0.98
aThe least significant difference among the means at the .05 probability level.
Source:Ref. 62.