270
c. R. Krishna Murti and T. S. S. Oikshith
Endosulfan (10 ppm) temporarily inhibits the growth of root and shoot in
germinating gram seeds in lower concentrations, the meristematic tissues recovering from the toxic effects after 10 days of treatment. Germinating seeds
implanted in agar slants mixed with different concentrations of endosulfan pick
up relative amounts of the insecticide within 24 hr. Accumulation of the insecticide in the seed suggests a dose dependency.
Field experiments are, however, open to the criticism that under natural
conditions or a change of weather plant surfaces may become contaminated with
the soil which has earlier received treatment with the insecticide and is later
translocated in the plant (Lichtenstein and Schulz, 1965; Saba and McDonald,
1967). Furthermore, the reaction between pesticide residues which penetrate
plant tissues and the constituents of plants are not fully known. Plant microsomes
have been investigated in connection with protein biosynthesis, but in general
the interaction of these organelles with the cyclodiene group and other types of
insecticides remains unexplored (Whaley et at., 1960).
Studies have been made on the uptake, translocation, and accumulation of
phosphamidon residues in mustard plants (Brassica compestris var. Sarsonprain).
Analysis of top, middle, and bottom portions of the plant sprayed with 0.03 and
0.06% of phosphamidon suggested that more residues were found on the top
portion of the plant. Accumulation of residue was maximum in the inflorescence
as compared to leaves sampled from the middle and bottom parts of the plant,
suggesting the translocation of the insecticide through cell sap (Yadav and Gupta,
1975).
De novo synthesis of acetylcholinesterase in roots of Pisum sativum and
the inhibition of the enzyme have been reported (Kasturi, 1978; Kasturi and
Vasantharaj an , 1976). Fensulphothion did not inhibit the de novo synthesis of
acetylcholinesterase in P. sativum but inhibited its activity (Kasturi, 1978).
Ideally, the ultimate evaluation of a pesticide should be made under conditions comparable to those occurring in actual use. Valuable information on the
metabolism of pesticides can also be obtained from comparative studies on insects
and other animals and on plants that are maintained and tested in a controlled
environment. It is of utmost importance that all the products formed during the
metabolism of pesticides be detected, identified, and evaluated individually and
in combination. The metabolism of different pesticides in plants has been reviewed extensively (Casida and Lykken, 1969; Kuhr, 1970; Menzer and Dautermann, 1970).
The persistence of pesticides has been the subject of research on a limited
scale by some institutes under the umbrella of the Indian Council of Agriculture
Research, mainly in the agricultural universities. Thus, work on residues has
been conducted on crops, such as sorghum, maize, cotton, sugar cane, and a
variety of vegetables (e.g., cabbage, cauliflower, tomato, brinjal). Organophosphorus compounds, carbamates, and chlorinated hydrocarbons have been
c. R. Krishna Murti and T. S. S. Oikshith
Endosulfan (10 ppm) temporarily inhibits the growth of root and shoot in
germinating gram seeds in lower concentrations, the meristematic tissues recovering from the toxic effects after 10 days of treatment. Germinating seeds
implanted in agar slants mixed with different concentrations of endosulfan pick
up relative amounts of the insecticide within 24 hr. Accumulation of the insecticide in the seed suggests a dose dependency.
Field experiments are, however, open to the criticism that under natural
conditions or a change of weather plant surfaces may become contaminated with
the soil which has earlier received treatment with the insecticide and is later
translocated in the plant (Lichtenstein and Schulz, 1965; Saba and McDonald,
1967). Furthermore, the reaction between pesticide residues which penetrate
plant tissues and the constituents of plants are not fully known. Plant microsomes
have been investigated in connection with protein biosynthesis, but in general
the interaction of these organelles with the cyclodiene group and other types of
insecticides remains unexplored (Whaley et at., 1960).
Studies have been made on the uptake, translocation, and accumulation of
phosphamidon residues in mustard plants (Brassica compestris var. Sarsonprain).
Analysis of top, middle, and bottom portions of the plant sprayed with 0.03 and
0.06% of phosphamidon suggested that more residues were found on the top
portion of the plant. Accumulation of residue was maximum in the inflorescence
as compared to leaves sampled from the middle and bottom parts of the plant,
suggesting the translocation of the insecticide through cell sap (Yadav and Gupta,
1975).
De novo synthesis of acetylcholinesterase in roots of Pisum sativum and
the inhibition of the enzyme have been reported (Kasturi, 1978; Kasturi and
Vasantharaj an , 1976). Fensulphothion did not inhibit the de novo synthesis of
acetylcholinesterase in P. sativum but inhibited its activity (Kasturi, 1978).
Ideally, the ultimate evaluation of a pesticide should be made under conditions comparable to those occurring in actual use. Valuable information on the
metabolism of pesticides can also be obtained from comparative studies on insects
and other animals and on plants that are maintained and tested in a controlled
environment. It is of utmost importance that all the products formed during the
metabolism of pesticides be detected, identified, and evaluated individually and
in combination. The metabolism of different pesticides in plants has been reviewed extensively (Casida and Lykken, 1969; Kuhr, 1970; Menzer and Dautermann, 1970).
The persistence of pesticides has been the subject of research on a limited
scale by some institutes under the umbrella of the Indian Council of Agriculture
Research, mainly in the agricultural universities. Thus, work on residues has
been conducted on crops, such as sorghum, maize, cotton, sugar cane, and a
variety of vegetables (e.g., cabbage, cauliflower, tomato, brinjal). Organophosphorus compounds, carbamates, and chlorinated hydrocarbons have been