Spectral reflectance characteristics of desert plants can be 
used in solving some important topics of photo-interpretation. Data on 
spectral reflectance published by many authors show the great variability 
of curves (W.D. Billings, R.J. Morris, 1951; N.G. Kharin, 1965; J.A. 
Howard, 1971, etc.). The analysis of regularities in distribution of the 
reflected energy is difficult because of the various combinations of bio 
logical features and site conditions. 
Our investigations were carried out during 1962 - 1973 in some 
regions of Turkmenistan. Experimental areas were located in three 
characteristic regions: 
1. Sandy desert where the psammophyte shrub vegetation is 
common, such as communities of Haloxylon aphyllum 3 H. persioum 3 Calligonum 
setosum with codominants Sphedra strobilaoea and Aellenia subaphylla. 
2. The second area was located in the hill country of South 
Turkmenistan. Stands of Pistaoia vera were studied here, they formed a 
typical landscape of semisavanna. Here were common some herbaceous 
plants: Cousinia bipinnata 3 Ferula badrakema 3 Astragalus agametious 3 Carex 
paohystylis etc. Serozem (grey semidesert soil) formed the dominant soil 
type here. 
3. As the third area a cultural landscape was taken (an oasis). 
It included gardens, tree plantings, irrigated fields and some other objects. 
Spectral reflectance was measured by the field spectrophoto 
meter (V.V. Kol'tsov, 1970) in the spectral band of 400 - 900 nm. As a 
standard surface, the white paper covered with a layer of barium sulfate was 
used. 
In this paper the author mainly considers spectral reflectance 
of plants in the spring aspect. Beyond this season the differences in 
spectral reflectance of various objects are less than that given here. 
A mathematical analysis was made with data obtained in the first 
area. It was known that to obtain a spectral reflectance curve of the whole 
spectrum a set of measurements should be made, at the interval of 25 nm or 10 
nm. The relationship between spectral reflectance at different wave lengths 
was not known. 
If that relationship were proved the reflectance would only be 
measured in certain points, and other points of the curve could be calculated. 
This hypothesis was tested on some groups of plants. 
Seventeen spectral reflectance curves of desert shrubs (Psammophy- 
tes) were treated. The following species were studied: Aellenia subaphylla , 
Calligonum setosum 3 Ephedra strobilaoea 3 Haloxylon aphyllum and Haloxylon 
persioum. This group of plants was considered as a statistical population 
having identical spectral properties. Six selected points were taken at 
different wave lengths 500 nm (x^), 550 nm (x^), 600 nm (x^), 660 nm (x^),