Carcinogenicity of the Herbicide Maleic Hydrazide

MALEIC hydrazide, l,2-dihydropyridazine-3,6-dione, was synthesized in 1947 (ref. 1) and has since become an important herbicide with uses including inhibition of sprouting in vegetables and stored root crops, prevention of sucker production in tobacco plants and growth control of grass, and foliage2, Maleic hydrazide is claimed to be selectively toxic to plants but not to bacteria, fungi, rodents or dogs3; it is, however, mutagenic to Drosophila melanogaster4 and Bacillus megatherium5, it reduces the fertility of pea aphids6, and produces cytotoxicity, mitotic inhibition and unbalanced growth in cultured mammalian cells7. The finding that maleic hydrazide induced breakage of heterochromatin besides mitotio inhibition in Vicia faba8 prompted this warning: “Since nearly all chromosome-breaking agents have so far proved to be cancer-producing as well, we must hope that the agricultural use of this new agent will not be encouraged before suitable tests are made.” Later tests claimed to show that maleic hydrazide is non-carcinogenic9. This conclusion seems at variance with the data on which it was based; for example, after weekly injections of 5 mg of maleic hydrazide as the diethanolamine salt during 14 months, an “unusually high” incidence of local sarcomas, in three out of fifty-two rats at risk with none in controls, was noted9. In other experiments, a total of 260 mg of maleic hydrazide7 in arachis oil was injected subcutaneously during 65 weeks, and three local sarcomas, one with a hepatoma, developed in three of six rats; it was concluded that the herbicide was clearly carcinogenic10.

SINCE MALEIC HYDRAZIDE (1,2-dihydropyridazine-3,6-dione) has been reported to inhibit the growth of numerous plants while having no apparent effect on others (Crafts, 1949; Currier and Crafts, 1950; Naylor and Davis, 1949; Schoene and Hoffman, 1949; U. S. Rubber Company, 1949), the feasibility of its use as a selective herbicide becomes evident. In that the hormone type weed-killers such as 2,4-dichlorophenoxyacetic acid and its derivatives are extremely injurious to cotton (Ergle and Dunlap, 1949), any new selective herbicides are of particular interest in the Cotton Belt. Crafts (1949) has stated that very promising results have been obtained in preliminary greenhouse experiments using maleic hydrazide for the control of weeds in cotton, particularly the control of numerous grasses. There are also some data in the literature indicating that cotton is not as susceptible to injury by maleic hydrazide as are some plants that may appear as weeds in the cotton field (Currier and Crafts, 1950; U. S. Rubber Company, 1949). This experiment, therefore, was designed to determine the effect of relatively high concentrations of maleic hydrazide on the growth and chemical composition of young cotton plants. The maleic hydrazide used in this experiment was supplied as the diethanolamine salt by the Naugatuck Chemical Division, U. S. Rubber Company, Naugatuck, Connecticut. METHODS.-Cotton, variety Stoneville 2B TPSA, was planted outside on June 18, in 2-gal. glazed jars filled with Lufkin fine sandy loam. The jars were thinned to a uniform stand of one plant per jar after 15 days. When the plants were 35 days old and had produced seven to eight true leaves, segregation was made into three groups. One lot was sprayed with 5 ml. per plant of an aqueous solution containing an equivalent of 2400 p. p. m. of maleic hydrazide, the second with 5 ml. per plant of 4800 p. p. m. of maleic hydrazide and the third remained untreated. These series will be hereafter designated as 2400, 4800, and control, respectively. Each of the maleic hydrazide solutions contained 2 ml. of Grasselli spreader per liter. Care was taken in each of the spray treatments that all parts of the plants were covered and that none of the solution was lost by run-off. At noon of the twenty-sixth day after application of the maleic hydrazide, the sixth and seventh leaves of all the above series were harvested for histological examination and chemical analysis. Histological material was taken from corresponding areas on

Removal of the developing inflorescence (topping) in tobacco (Nicotiana tabacumL.) production will result in higher leaf yield and increased alkaloid content. Unfortunately, topping will remove axillary bud (sucker) inhibition. To achieve the higher yields and alkaloid content growers must control the development of suckers through manual or chemical means. Because hand‐suckering is a menial task, the use of maleic hydrazide (MH) rapidly became the cultural practice to control sucker growth, but its use was severely questioned by the industry. The Regional Tobacco Growth Regulator Committee was established in 1963 to evaluate tobacco treated with various experimental chemical sucker‐controlling agents as alternatives to MH. Regional committee test data accumulated from 1963 through 1981 by federal and state researchers were used to compare cured leaf from MH‐treated plants with hand‐suckered plants, the control treatments. Yield and value per hectare were higher from the use of MH while dollars per 100 kg were the same for both kinds of treatments in both classes of tobacco. Tobacco leaf experts were able to visually differentiate between MH‐treated and hand‐suckered flue‐cured but not burley tobaccos. Chemical analyses indicated that percent total alkaloids and percent total ash were less in MH‐treated flue‐cured and burley tobaccos. Alkalinity of water soluble ash increased from MH treatment. Total volatile bases minus nicotine (as ammonia) decreased significantly in flue‐cured tobacco from MH treatment while the increase found in burley from MH treatment was not. Maleic hydrazide treatment significantly increased per cent reducing sugars in flue‐cured tobacco, but had no effect on percent total N in burley. Physical analyses indicated that values for filling capacity were significantly lower and equilibrium moisture content significantly higher in MH‐treated tobaccos.

Data from experiments conducted at one location in 1980 and two in 1981 showed that MH residues were greater on flue-cured tobacco after application of a K-MH (potassium salt of MH) formulation than of a DEA-MH (diethanolamine salt of MH) formulation at the same rate of active ingredient. On cured lamina mean residue values from K-MH for the two locations in 1981 were 48 % and 61 % greater than those for DEA-MH. There was no apparent loss of residue for either formulation during the curing process. Sucker control was less efficient with the DEA-MH than with the K-MH formulation and was associated with the level of residue in the leaf.

Action of maleic hydrazide (MH) as an antimitotic agent in axillary bud tissues of Nicotiana tabacum L was confirmed in a study with foliar applications Upper axillary meristems on topped and MH-treated plants were more severely affected than those in middle and lower stalk positions These observations may explain the late season growth of suckers on the lower portions of treated field-grown plants Cell divisions were not observed in the tunica-corpus region of meristems of upper buds taken 1 day after topping and MH treatment, but an occasional division figure was found in the provascular strands and in the leaf primordia The tunica-corpus had lost most of its layered organization 4 days after treatment and all of it after 7 days Also, after 7 days, cell walls were thickened, and many cells of the meristem had condensed material in a metaphasal position Little or no necrosis was evident 15 days after treatment, but regeneration of tissues was not evident, thus indicating the effectiveness of MH as a sucker-controlling agent Size of cells and nuclei in the tunica-corpus region in meristems of primary bud tissues did not differ between MH-treated and untreated plants However, the diameter of the meristematic dome and the height of the meristematic region above the rib meristem were significantly less in MH-treated than in untreated tissues Changes in these two parameters also indicated that MH treatment controlled growth by inhibiting cell division

Multiple regression analysis of the relationships between tobacco mosaic virus multiplication, the severity of mosaic symptoms, and the growth of tobacco and tomato

Understanding the impact of rhizosphere soil properties on tobacco growth after land consolidation is crucial for optimizing agricultural practices. This study investigated the relationship between rhizosphere soil biochemical properties, enzymatic activities, and tobacco growth in three fields in Guizhou province. We found no significant differences in the biochemical properties, soil quality index, or enzymatic activities between tobacco plants exhibiting Good and Bad growth performance. Soil microbial activity was primarily limited by phosphorus, but there were no significant differences in carbon, nitrogen, or phosphorus limitations between the two growth performance. Additionally, soil ecosystem multifunctionality showed no significant correlation with tobacco plant performance. These results suggest that while rhizosphere soil properties play a role, other factors such as microbial communities and management practices may have a more significant influence on tobacco growth after land consolidation. Further research is needed to explore these complex interactions and develop strategies to enhance tobacco production in post-consolidation environments.

Response of growth of deli tobacco (Nicotiana tabaccum (L.)) on some kind of lime and soil types in North Sumatera. Deli tobacco is variety of tobacco that is used as world top quality wrapper of cigar . But, in last years production of deli tobacco had been decreasing because of land degradation. Consequently, it is important to develop deli tobacco plantation to another soil types that is combine by giving some kind of lime. The aim of this research was to examine growth of deli tobacco (Nicotiana tabaccum (L.)) on some kind of lime and soil types in Noerth Sumatera. The research was conducted in the land of the Research Center of Deli Tobacco (BPTD) Sampali PTPN II, starting from February to May 2012, using a randomized block design (RBD) factorial with two factors and three replications . The first factor is soil types (alluvial, andosol, hidromorf, ultisol). The second factor is the kind of lime (dolomite, calsit, kaptan). The results showed that soil types significantly affect on plant height, diameter of stem, number of leave, thick leaf sand, 1 foot thick leaves, long leaves sand, 1 foot long leaves, leaf width sand, and 1 foot wide leaves. Kind of Lime and the interaction between soil and lime is not significantly affect for all parameter observed. Keywords: soil, lime, Tobacco Deli.

Tobacco (Nicotiana tabacum; C3) plants increase their water use efficiency (WUE) under abiotic stress and are suggested to show characteristics of C4 photosynthesis in stems, petioles, and transmitting tract cells. The tobacco stress-induced Aquaporin1 (NtAQP1) functions as both water and CO(2) channel. In tobacco plants, overexpression of NtAQP1 increases leaf net photosynthesis (A(N)), mesophyll CO(2) conductance, and stomatal conductance, whereas its silencing reduces root hydraulic conductivity (L(p)). Nevertheless, interaction between NtAQP1 leaf and root activities and its impact on plant WUE and productivity under normal and stress conditions have never been suggested. Thus, the aim of this study was to suggest a role for NtAQP1 in plant WUE, stress resistance, and productivity. Expressing NtAQP1 in tomato (Solanum lycopersicum) plants (TOM-NtAQP1) resulted in higher stomatal conductance, whole-plant transpiration, and A(N) under all conditions tested. In contrast to controls, where, under salt stress, L(p) decreased more than 3-fold, TOM-NtAQP1 plants, similar to maize (Zea mays; C4) plants, did not reduce L(p) dramatically (only by approximately 40%). Reciprocal grafting provided novel evidence for NtAQP1's role in preventing hydraulic failure and maintaining the whole-plant transpiration rate. Our results revealed independent, albeit closely related, NtAQP1 activities in roots and leaves. This dual activity, which increases the plant's water use and A(N) under optimal and stress conditions, resulted in improved WUE. Consequently, it contributed to the plant's stress resistance in terms of yield production under all tested conditions, as demonstrated in both tomato and Arabidopsis (Arabidopsis thaliana) plants constitutively expressing NtAQP1. The putative involvement of NtAQP1 in tobacco's C4-like photosynthesis characteristics is discussed.

A new metabolite of maleic hydrazide (MH; 1,2-dihydro-3,6-pyridazinedione) was isolated from MH-treated tobacco (Nicotiana tabacum L.) plants. The purified metabolite was identified as MH-N-β-D-glucoside by means of TLC, FAB-MS, 1H-NMR, and 13C-NMR analyses.

Preceding crops, depending on its type, has been commonly thought having positive or negative effect on subsequent plant growth, yield and even quality, but which type is favorable for next crops is worthy of investigating in tobacco production. Two field experiments were conducted with preceding crops of rape, wheat, barley, green manure and fallow in two different climatic sites, Shilin and Xundian in Yunnan province, respectively. The results showed that tobacco plants’ growth, maturity, yield, economic value and smoking quality were significantly affected by the preceding crops. In both sites, tobacco with preceding crop of wheat grew rapidly at the early growth stage and matured earlier at the later stage, but it grew slowly at the early stage, vigorously at the late stage, and delayed in maturity in the field with preceding crop of green manure. The yield for leaf was the highest at two sites where the preceding crops were green manure and fallow. The economic value was the highest when the preceding crops were barley, green manure or rape in Shilin, and barley, green manure or wheat in Xundian. For smoking quality, it was better to plant tobacco following rape or wheat in Shilin, while following wheat or green manure in Xundian. In general, rape is the optimal preceding crop for tobacco in Shilin where the climate during tobacco growth is relatively hot, while wheat or green manure is the better one in Xundian with relatively low temperature during the field growth stage.

Duvatrienediol is a diterpene specifically occurred in tobacco plants and thought to be a precursor of tobacco aroma. Green tobacco leaves contained 0.2_??_1% of duvatrienediol per dry weight and it was corresponded to 30_??_60% of leaf surface lipid. Leaves on upper stalk position contained more of leaf surface lipid and duvatrienediol. In leaves on each stalk position, leaf surface lipid and duvatrienediol contents increased with leaf growth and decreased by over-maturation. Production of leaf surface lipid and duvatrienediol was affected by soil conditions or applied amount of nitrogen fertilizer. Both leaf surface lipid and duvatrienediol were decreased during curing of tobacco leaves, but the change in the latter was more drastic. Comparing to leaf surface lipid, changes in cytoplasmic lipid were less during growth and senescence of tobacco leaves.

Pseudomonas sp. TK35-L enhances tobacco root development and growth by inducing HRGPnt3 expression in plant lateral root formation

Effects of biochar amendment and reduced irrigation on growth, physiology, water-use efficiency and nutrients uptake of tobacco (Nicotiana tabacum L.) on two different soil types

Microbial Inoculants: Silver Bullet or Microbial Jurassic Park?