Search

Flax (Linum usitatissimum L.) is an important industrial crop in fiber production. This study is aimed to isolate specific germplazms with high potassium efficiency. Totally 50 flax germplazms were...

Flax (Linum usitatissimum L.) is an important industrial crop, and its seeds are rich in a variety of functional nutrition and health components. Therefore, flaxseed is not only an important raw ma...

Wild marigold (Tagetes minuta L.) is a highly demanded aromatic plant, having great industrial value. Recently farmers are more interested in its cultivation and are opting it in their cropping sys...

In this review, different research works related to Taxonomy, cytogenetics, tissue culture, Biotechnology, Agronomy, phytochemistry, pharmacology and biological activity as well as its commercial uses of Tagetes species including all the biological and chemical activities mainly T. minuta, T. patula and T. erecta have been compiled. The review also highlights the chemical structures and commercial uses of essential oil and its components of its unique biological activity being used as agrochemical, food and colorants and nutritional supplement and cosmetic industry. This review work also focus on commercial cultivation of T. minuta for its oil and T. patula and T. erecta find floriculture use and also raw material for commercial production of several kinds of compounds.

Hybridization of species belonging to the genus Mentha is quite common. However, the indicators of hybridity are many and make Mentha hybrids' identification difficult. By using the same molecular strategy that allowed us to unequivocally identify some Mentha species, we amplified the Not-Transcribed-Spacer (NTS) of the 5S-rRNA gene to characterize the industrial crop peppermint, M. × piperita and some important Mentha interspecific hybrids: M. × dalmatica, M. × dumetorum, M. × rotundifolia, M. × maximilianea, M. × smithiana, M. × verticillata, M. × villosa. DNA amplification, sequence and cluster analysis revealed differences in the 5S-rRNA NTS region of Mentha hybrids. Peppermint and all other hybrids were unequivocally discriminated by RFLP analysis by using TaqI restriction enzyme, while a further discrimination between M. × dumetorum and M. × verticillata was obtained by XhoI restriction enzyme. Essential oil composition showed clustering patterns similar to DNA fingerprint, with a clear discriminati...

Mints (Mentha species) are being cultivated as an industrial crop for the production of their essential oils in northern Indian plains. In sub-tropical regions, Mentha species are cultivated as a spring–summer crop for their essential oils. However, for planting material production, these species are planted in the rainy season (August). The purpose of this study was to analyze and compare the essential oil quality of rain–winter crops (the planting material-producing crop) with the spring–summer crops (main crops) of Mentha spicata cv. MSS-5, Mentha spicata cv. Ganga, Mentha citrata cv. Kiran, Mentha arvensis cv. CIMAP-Saryu and Mentha x piperita cv. Kukrail. The essential oil yield varied from 0.40% to 1.10% in the main cropping season, whereas it varied from 0.15% to 0.60% in the planting material-producing cropping season. Gas chromatography (GC) and GC–mass spectrometry (GC–MS) analyses resulted in the identification of sixty constituents, representing 93.51–99.71% of the oil compositions. Monoterpen...

A study was carried out over 2 years (2009 and 2010) at the CSIR–Institute of Himalayan Bioresource Technology, Palampur, India, to investigate the effect of irradiance stress and plant spacing on growth, biomass yield, essential oil content and composition in wild marigold (Tagetes minuta L.). Four shade levels (0%, 25%, 50% and 75%) and three plant spacing (45 × 30, 45 × 45 and 60 × 45 cm) were tested as per split plot design. Heavy shading (50% and 75%) strongly reduced the total essential oil content in fresh leaves and flowers. The essential oil content of leaves, flowers and the total oil increased up to the 25% shade level and declined thereafter, with a decrease in irradiance level. Ocimene and dihydrotagetones concentration in leaf oil decreased with decrease in irradiance level; however, tagetone and ocimenone showed the reverse trend. In flower oil, ocimene decreased with an increase in shade levels. Fresh leaf, stem, flower, leaf + flower biomass, and total biomass was significantly higher in ...

Jerusalem artichoke (Helianthus tuberosus L.), an important crop, containing over 50% inulin in its tubers on a dry weight basis is an agricultural and industrial crop with a great potential for production of ethanol and industrial products. Inulin is a good substrate for bioethanol production. Saccharomyces cerevisiae 6525 can produce high concentrations of ethanol, but it cannot synthesize inulinase. In this study, a new integration vector carrying inuA1 gene encoding exoinulinase was constructed and transformed into 18SrDNA site of industrial strain S. cerevisiae 6525. The obtained transformant, BR8, produced 1.1UmL(-1) inulinase activity within 72h and the dry cell weight reached 12.3gL(-1) within 48h. In a small-scale fermentation, BR8 produced 9.5% (v/v) ethanol, with a productivity rate of 0.385g ethanol per gram inulin, while wild-type S. cerevisiae 6525 produced only 3.3% (v/v) ethanol in the same conditions. In a 5-L fermentation, BR8 produced 14.0% (v/v) ethanol in fermentation medium containing inulin and 1% (w/v) (NH4)(2)SO4. The engineered S. cerevisiae 6525 carrying inuA1 converted pure nonhydrolyzed inulin directly into high concentrations of ethanol.

Excess nitrogen fertilization of leafy vegetables may cause undesirable accumulation of nitrates and a decrease in essential amino acids, resulting in a decrease in protein nutritional quality. We investigated the effect of nitrogen (N) fertilization (0, 100 or 200 kg N ha−1) on the nutritional quality of red head chicory proteins. Lysine limited biological value of proteins in the control (0 N) as well as fertilized samples. The lysine content and protein biological value according to Mitchell and Block method decreased significantly (p ≤ 0.05) with 100 and 200 kg ha−1 nitrogen applied relative to control. The Oser's essential amino acid index and protein biological value were relatively high and did not decrease with increased N fertilization. The correlation between the protein biological value of red head chicory and crude protein levels was negative (p < 0.001). Protein nutritional quality was optimal for adults and lower than optimal for children aged 2–5 and 10–12 years.

Sugar beet (Beta vulgaris L.) is an important industrial crop, being one of only two plant sources from which sucrose (i.e., sugar) can be economically produced. Despite its relatively short period of cultivation (ca. 200 years), its yield and quality parameters have been significantly improved by conventional breeding methods. However, during the last two decades or so, advanced in vitro culture and genetic transformation technologies have been incorporated with classical breeding programs, the main aim being the production of herbicide-and salt-tolerant, disease- and pest-resistant cultivars. Among the many applications of in vitro culture techniques, sugar beet has benefited the most from haploid plant production, protoplast culture, and somaclonal variation and in vitro cell selection. Several genetic transformation technologies have been developed, such as Agrobacterium-meditated, PEG-mediated, particle bombardment, electroporation, sonication and somatic hybridization, the first two being the most s...

This is the third in a series of “Hemp production notes,” which focuses on the unique challenge of growing hemp at high latitudes in the European Community. This paper briefly reviews the historical considerations of hemp in Finland, addresses some of the problems inherent at high latitudes and identifies specific market potentials for the Nordic production of hemp seed as an industrial crop.

Roselle (Hibiscus sabdariffa L.) is widely cultivated in the forest and savannah ecological zones of Nigeria. It has a lot of potential as an industrial crop. Smallholder and resource poor farmers grow it. Roselle is popularly grown for its fiber content and for its leaves, calyces, roots, seeds, which are used either for industrial, medical, commercial, or domestic uses. Its use as a fiber crop is yet to be exploited in Nigeria. This paper discusses the agronomy, utilization, and commercialization of the crop. Future research needs are also discussed.

Barley has assumed the status of an industrial crop in India over recent years. Once grown as a rain-fed crop with minimum input, presently it is grown under optimum input to produce plump and mealy grains required for malting. The increased use of nitrogenous fertilizer and irrigation is likely to increase the incidence of biotic stresses. Aphids are the most widely distributed and serious threat to this crop under favourable conditions. Among the various diseases infecting barley, yellow rust is the most important in India. Germplasm lines maintained at the Directorate of Wheat Research, Karnal (India) were evaluated both against corn leaf aphid (Rhopalosiphum maidis) and yellow rust (Puccinia striiformis). Resistant lines were tested over 3 years under field conditions and thereafter under polyhouse conditions to confirm their resistance. One of the lines (BCU 284) was found to be resistant against both corn leaf aphid and yellow rust and is, therefore, potentially of great value to barley breeders. BC...

This paper deals with the most important Swedish agriculture crops in relation to (i) Landsat-based spectral differences, (ii) mono- and multi-temporal Landsat classification measured as producer's, user's and Kappa accuracy and (iii) Landsat classification determined as area estimation accuracy. The potential of satellite data for crop monitoring in Sweden was found to be rather low for most crops except rape seed and sugar beet. Concerning these crops results indicated a possible operational applicability.

Vernonia (Vernonia galamensis) is a new industrial crop that could offer a naturally epoxidized oil with great economic value. The oil content and fatty acid composition of 10 selected lines of V. galamensis variety ethiopica were analysed to study the variability among and within lines. Lines showed oil content varying from 24–29% and varying ranges of vernolic acid (7377%), linoleic acid (12–14%), oleic acid (3.5–5.5%), palmitic acid (2.4–2.9%) and stearic acid (2.3–2.8%). Entries collected from southern Ethiopia had higher oil content than those from eastern Ethiopia. Two accessions, Vge-10 with the highest contents of oil (29%) and vernolic acid (77%) and Vge-3 with the highest vernolic acid content (77%) were identified as promising parents for improving the quantity of oil and vernolic acid.

1) Rice, spring wheat, maize, soybean, field bean, potato and sugarbeet were grown in Hokkaido with good management, and the difference in economic yield among these crop species was discussed on the basis of differences in growth duration, crop growth rate, and behavior of 14C assimilated at different growth stages. 2) The economic yield is higher in maize, potato and sugarbeet than in other crops. The high yield is due to a high photosynthetic rate per unit leaf area in maize, to a high sink capacity of the tubers in potato, and to a long growth duration of the leaves as weil as the tap. root in sugarbeet. 3) The economic yield is lower in spring wheat, soybean and field bean. Tbe low yield is due to a short growth duration in spring wheat, and to an unfavorable leaf display and a large respiratory loss of photosynthates during grain ripening to produce proteins and lipids in Leguminosae crops.

The effects of abscisic acid (ABA) and K deficiency on leaf diffusive resistance were determined on soyabean (Glycine max L., cv. Amsoy 71) plants. Leaf diffusive resistance was measured on the lower surfaces of the primary leaves. Changes in leaf diffusive resistance, determined with the transient porometer, were found similar in both of the treatments compared with the control plants. 14C‐ABA (Abscisic acid) was given to roots of K‐deficient plants and specific radioactivities were found to increase in the primary leaves compared to K‐sufficient plants. Plants subjected to a K deficient stress induced through the roots were able to adapt to their environment by closing their stomata. This suggests that such adaptations are made possible by increasing the content of ABA in

Electrophoresis of a root plasmalemma fraction from three sugar beet cultivars with different iron uptake capacities revealed a 25 kilodalton (kd) protein which is produced in enhanced amounts in response to Fe deficiency in a manner corresponding to the Fe uptake capacities of the three cultivars. An assay was developed to measure the plasmalemma‐bound ferric iron reductase. Using this assay, we were able to detect differences in specific activity of the reductase among the three cultivars but not increases in activity in response to iron stress. The results suggest that a 25 kD plasma lemma‐bound protein could be involved in the dramatically enhanced uptake of Fe which occurs when Fe is resupplied to Fe deficient sugar beets.

Studies were conducted to examine the annual fluctuations of disease intensity in potato wart disease. Each experiment ran over many months and consisted of monthly, weekly and daily inoculations of Arran Victory potato tubers with Synchytrium endobioticum pathotype 2. Treated plants were harvested 2 months after inoculation. The experiments were conducted in the greenhouse and controlled environment growth room. A trimodal waveform (of diminishing amplitude) of percent infections was detected. The three periods of increased infection coincided with the major periods of host susceptibility. A periodicity of about 8 weeks between these infection periods was evident. This paper is part of a continuing study of pathogenesis of S. endobioticum.

The absorption of 99‐Mo by excised tobacco, Nicotiana tabacum L. c.v. KY‐14, roots was examined. Lowered temperature, anaerobic conditions and various inhibitors of oxidative phosphorylation decreased the absorption of Mo, suggesting that the absorption of Mo was metabolism‐dependent. Similar results were obtained with the absorption of 86‐Rb. The absorption of 99‐Mo decreased exponentially with an increase in pH. The apparent Km for the absorption of Mo was 15 μM, although at high concentrations of Mo, the absorption of Mo occurs primarily by passive processes.

Aspergillus flavus and Aspergillus niger commonly co-occur in preharvest maize and one report suggests that this association promotes a greater incidence of aflatoxin. Other studies have shown that Aspergillus niger can prevent, or substantially reduce, aflatoxin formation by Aspergillus flavus in autoclaved maize kernels, and this led us to examine the effect of A. niger on aflatoxin formation by A. flavus in preharvest maize where the bulk of aflatoxin accumulation occurs. Samples of kernels simultaneously wound-inoculated with equivalent numbers of A. flavus and A. niger conidia showed substantial aflatoxin contamination (mean = 9900 ppb) even though significantly more (P = .04) aflatoxin was produced in kernels wound-inoculated only with A. flavus (mean = 36,700). These same wounded kernels had a mean sample pH of 5.45 ± 0.44, well above substrate acidity levels (

A study was conducted to evaluate the use of P vectors to predict the amount of P required on a yearly basis to maintain a constant solution‐solid phase P relationship in an irrigated calcareous and a dryland acid soil. Irrigated potato‐spring barley and dryland spring pea spring‐barley crop rotations established at the two locations. Mono‐calcium phosphate (0–45–0) was applied annually at five levels, ranging from 0–4 times estimated crop removal. Phosphorus vectors were determined on soil samples by equilibration with standard P solutions. Yields tended to increase with added P on the calcareous soil; however, significant responses were not recorded at either location. Consequently, critical P vectors were not established. A constant solution‐solid phase P relationship was maintained by addition of P equal to that removed by the crop on the calcareous soil. A constant solution‐solid phase P relationship was not maintained on the acid soil.

Six potato genotypes were tested to evaluate the effect of K nutrition on frost tolerance by measuring electrolyte leakage from leaves exposed to various freezing temperatures. Potato genotypes were selected through the known range of low temperature survival tolerance within tuber‐bearing Solanum species. An experiment was conducted using a soil high in K; and then nutrient solution experiments were conducted in the open environments of La Molina. Commercial K fertilizers, at different levels, were unable to increase significantly the frost tolerance in a common potato cultivar grown in a soil high in K. In nutrient solutions experiments, with plants grown without any hardening process, we found that there is a genetically related capacity to respond through K nutrition to increase frost tolerance among potatoes. The common commercial potato, S. tuberosum, did not change significantly its freezing sensitivity when K nutrition was varied. But S. curtilobum, which is grown by low income farmers in...

1) Relative importance of parameters, which determine the differences of economic yield (ye, dry matter production of harvesting organ) and nitrogen response among major crops in Hokkaido, northern Japan, were evaluated by using the following formula. where TGD, total growth duration; SR, solar radiation per day; ER, energy receiving ratio by crop population; EC, energy conversion ratio to produce primary photosynthates; PR, partition ratio of primary photosynthates to harvesting organ; and CEe, conversion efficiency of harvesting organ. 2) The Ye was in the order of sugarbeet> potato> maize> rice>soybean. 3) Major yield-determining parameters were EC and TGD in rice, PR in maize, CEe, EC and TGD in soybean, TGD in potato, and EC in sugarbeet. Maize and potato had a higher EC and PR, respectively, in comparison to other crops. 4) The difference of ER among crops was small if a whole growth cycle was considered. However. the changes of the light transmission ratio during the growth were different among cro...

In the Japanese warm areas, as a result of intensive and repeated potato cropping, common scab, a soil-borne disease has become a serious problem. The soil moisture level has been shown to be an important factor affecting the incidence of common scab. That is, a high level of soil moisture reduces the severity of common scab. However, in this investigation, although during the spring cropping precipitation was abundant, a large number of tubers showing scab lesions were produced. The results indicate that the soil moisture level may not be an important factor affecting the incidence of potato scab in the humid region. To identify other factors which may affect scab severity, the relation between sugar content in the peel of potato tuber and the incidence of common scab was investigated. Generally, the amount of reducing sugar in the tuber peel increased gradually with the growth of the tubers, then reached a maximum level two weeks after the start of tuber formation, and thereafter declined. The period co...

A series of experiments was conducted to study the effects of apical meristem removal on sulfate and nitrate reduction in ‘Ky14’ tobacco plants (Nicotiana tabacum L.). Apical meristem removal is expected to modify N metabolism since it causes an increase in the synthesis of nicotine in the roots and its accumulation in shoots. There may not be any such complementary effect on S metabolism. Further, the experiments were designed to study the effects of apical meristem removal on the interaction of nitrate (NO3) and sulfate (SO4) reduction. Activities of ATP sulfurylase and NO3 reductase, the first steps of SO4 and NO3 reduction, respectively, have been considered indicators of the state of regulation of the assimilatory pathways of SO4 and NO3. The effect of apical meristem removal on the activities of the above enzymes in the leaf tissue and the interrelationship between them was examined. Removal of the apical meristem resulted in a large increase in nicotine concentration, a large increase in t...

SummaryIn a field experiment on calcareous soil the application of NAA (10 ppm) and Mixtalol (2 ppm) as a foliar spray combined with seed treatment increased the chlorophyll content of the leaves by 34.3% and 35.03%, respectively over the control. Foliar application of Fe-EDDHA (0.2%) and H2SO4 (0.1%) increased the leaf chlorophyll content by 29.92% and 33.47%, respectively. The application of NAA, GA and Mixtalol as seed treatment alone increased the green pod yield of peas by 66.76% and 76.38%, respectively. Foliar application of Fe-EDDHA and H2SO4 increased the pod yield by 75.9% and 88.02%. NAA and Mixtalol as seed treatment combined with foliar spray increased pod yield by 85.5% and 89.03%, respectively over the control.

In this review we examine the characteristics of chill-induced, photoinhibitory damage to the thylakoid membranes of maize leaves and evaluate their potential contributions to decreases in photosynthetic productivity of the crop

Experiments with a few crop plants have revealed the existence of different mechanisms of Fe‐stress tolerance. However, there are some physiological responses obtained in common, like pH reduction, release of reductant chemicals, and chlorosis recovery in the Fe‐efficient cultivars. Five cultivars of tobacco were subjected to Fe‐deficiency stress in nutrient culture. All of them exhibited varying degrees of chlorosis, released riboflavin into the medium at different stages of growth, and reduced the pH. Studies with ash gourd and pumpkin showed that the former was susceptible and the latter tolerant to Fe‐stress. The pH of the medium was reduced followed by release of riboflavin and formation of swelling and yellowing of root‐tip in pumpkin. The ash gourd cultivar CO‐2 responded to treatment with 100 ppm phthalic acid by producing new green leaves.

The DRIS (Diagnosis and Recommendation Integrated System) procedure for assessing nutritional status of plants by leaf analyses utilizes standard values ("norms") for nutrient ratios that have been obtained from high‐yielding populations. Examination of 1086 sets of yield and analytical data from 28 field experiments with potato (Solanum tuberosum L.) conducted over a period of 8 years on irrigated Boroll soils in semi‐arid southern Alberta, Canada, established ratios among N, P, K, and Ca that were significantly less variable in the high‐yielding (≥40 t/ha) than in the low‐yielding population. Another set of ratios for N, P, K, and Mg, determined from 1260 data sets obtained from 5 years of experimentation on Spodosol soils in the temperate humid area of Nova Scotia, were similar to those from the Boroll soils. Our standard values differed from those reported for potatoes grown on South African soils. Nutrient indices of deficiency, which were computed to integrate the degree of departure of eac...

This study-examines the use of multitemporal Landsat satellite radiance values to classify the potato crop. Using this data, the distribution and area of the crop within the Kincardine and Deeside District of Grampian Region is presented. The area and individual locations identified are found to be comparable to Department of Agriculture and Fisheries for Scotland statistical returns. The study also integrates the spatial distribution database with soil and potential water deficit data to generate statistical information on the proportion of the potato crop growing on drought susceptible soils.

Losses of volatile sulfur (S) compounds were measured from intact plants of 22 species including tropical and temperate crop and pasture species grown under glasshouse conditions. All species released substantial amounts of S during a 22‐hour collection period. The amounts lost ranged from 0.13 μg S g dry weight of shoot‐1 22 hours‐1 in barrel medic to 2.68 μg S g dry weight of shoot‐1 22 hours‐1 in rape. These losses represented 0.005% of the total S in the shoot in barrel medic and 0.92% in rape. There was no obvious division between temperate and tropical species in terms of the amounts of volatile sulfur compounds released, but the evidence suggested that tropical species released a different spectrum of volatile sulfur compounds from temperate species. Thus in tropical grasses and legumes, a higher proportion of the total volatiles was recovered in cold traps, whereas in temperate grasses and legumes, a higher proportion of the total volatiles was recovered in activated carbon traps located ...

Replicated field experiments were conducted during autumn 1982–83 at Jalandhar (Punjab) for evaluating an insecticidal schedule involving soil application of aldicarb (Temik) 10 G and carbofuran (Furadan) 3 G @ 1.0 and 1.5 kg a.i./ha in two different protocols viz.; (i) single full dose application of granules in furrows at planting and (ii) equal split dose application of granules (half in furrows at planting + remaining half dose near plants base at earthing up), found effective for aphid control, for residues. The findings indicate that aldicarb and carbofuran residues in unprocessed (unwashed, unboiled and unpeeled) potatoes from 1.0 and 1.5 kg a.i./ha doses applied in single full dose in furrows at planting (in the first protocol) persisted above the tolerance limits (0.50 ppm each for aldicarb and carbofuran) up to 70 days. Aldicarb residues in such unprocessed potatoes persisted above the tolerance limit up to 70/49 and 80/59 days respectively, from 1.0 and 1.5 kg a.i./ha doses when applie...

A detailed series of observations were made throughout the year on in vitro collections of Synchytrium endobioticum, the causal agent of wart disease of potato. Each month a fresh sample of the fungus estimated at 10.000 spores per dish was incubated in water. The numbers of resting spores with attached vesicles and numbers of subsequently empty ones were estimated for 22 days each month. The numbers of empty resting spores which accumulated each month varied from month to month, and from week to week in any month. Large numbers of empty spores indicated massive germination. Germination was greatest in the spring/early summer season and late fall/early winter. Vesicle production also varied, and the rates of germination of vesicles varied during the year so that vesicles remained ungerminated longest in winter, and to some extent in sumer and late fall. Vesicle production was greatest on the average by the start of the third week of incubation. The wax and wane of empty spore production explains ...

Greenhouse experiments were conducted to study the P and Mo interactions during uptake by burley tobacco (Nicotiana tabacum L., cv. ‘Ky 14') and the effect of their interactions on plant dry matter and Mo concentration. In Experiment 1, plants were grown in an intermittently irrigated gravel culture system. The nutrient variables were Mo (0–0.63 μeq/L) and P (0 to 1.8 meq/L). Experiment 2 was conducted in soil‐sand mixtures. The soil types used were Shelbyville silt loam (Mollic Hapludalf) and Baxter silt loam (Typic Paleudalf) each containing, respectively, 36 and 368 kg P/ha by the Bray 1 soil test. Treatments consisted of four rates of P (0, 84, 168, and 336 kg/ha) and five rates of Na2MoO4‐2H2O (0, 0.56, 1.12, 2.24, and 4.48 kg Mo/ha). In gravel culture a significant synergistic Mo × P interaction occurred for dry weight, but singly the effect of P was greater than Mo. Similarly, significant positive Mo × P interactions occurred for Mo concentrations in both gravel and soil culture. As contra...

(1) Rice, winter wheat, maize, soybean, potato, and sugarbeet were grown with 0, 100, 200, and 300 kg N/ha, and the efficiency of fertilizer-N to produce dry matter of harvesting organs (yield) was analyzed using the following equations: Y=N(plant) • N-E=N(plant) • HI(N)/N%(h.o.), where Y=Yield, N(plant)=N accumulated in plants=Soil-N absorbed+(fertiIizer-N applied)-(absorption percentage of fertilizer-N), N-E=Efficiency of N(plant) for Y, HI(N)= Harvest index of N, and N%(h.o.)=N% of harvesting organ. (2) The yield was generally in the order of sugarbeet, potato > maize, wheat, rice > soybean. (3) The maximum yield was obtained at 100 kg N/ha in sugarbeet and rice, 200 kg N/ ha in wheat, and 300 kg N/ha in maize, potato, and soybean. The protein yield of potato at 200-300 kg N/ha was as high as that of soybean. (4) With the increase of the fertilizer-N level, the N(plant) increased, the absorption percentage decreased, the N-E decreased, the HI(N) decreased, and the N%(h.o.) increased. The magnitude of t...

Seedlings of tomato and tobacco were V‐grafted reciprocally and intraspecifically and cultured for 22 days in 2‐liter containers of nutrient solution with normal or no iron. The pH of solutions containing iron increased slightly, while the pH of solutions with no iron decreased. There was little decrease in the pH of tomato grafts on tomato, while the pH of other combinations decreased from 1.5 to 3.1 pH units. Riboflavin concentrations in nutrient solution were highest with tobacco on tobacco, and were about one‐third less with tomato on tobacco. The riboflavin values for tobacco on tomato and tomato on tomato were barely detectable like those for plants supplied with iron. Roots of iron‐deficient tobacco plants at harvest contained much more total riboflavin than roots of iron‐deficient tomato plants and roots of iron‐supplied plants contained less total riboflavin than iron‐deficient plants. Total riboflavin in roots of tobacco plants exceeded that in roots of tomato plants. The total riboflav...

Since the outbreak of potato cyst nematode Globodera pallida at Pukekohe in 1972 there has been discussion over the efficiency of the method used by field officers of the New Zealand Ministry of Agriculture and Fisheries to detect infestations. This paper compares the relative merits of the 2 principal methods for detection of potato cyst nematode (PCN). These are: taking soil samples before a host crop is grown to examine the soil for presence of dormant eggfilled cysts; and examination of live potato plant roots for the presence of developing PCN females. Examination of live potato roots is shown to be 80–120 times more efficient in detecting and locating foci of infection than is soil sampling.

Greenhouse-grown potato plants were exposed to nitrogen dioxide in an exposure chamber to determine the rate of NO/sub 2/ uptake at concentrations from 228 to 817 ..mu..g/m/sup 3/ (0.12-0.43 ppm). Results show that a consistent increase in uptake rate accompanied an increase in NO/sub 2/ exposure concentrations. Exposure in the range of concentration had no significant effect on leaf diffusive resistance.