Effect of soil and water salinity on tomato growth

The yield of tomatoes for processing (Lycopersicon esculentum var. VF145 B. 7879) grown in artificially salinized plots, was reduced by 10% for every 1.5 mmhos/cm increase in EC_e above 2.0 mmhos/cm. Yield reduction was the same for equal mean soil salinities regardless of leaching and the rate of salt accumulation in the soil. Total soluble solids content increased with increasing salinity to offset, to a large extent, the yield reduction. Reduction in water uptake, as a result of an increase in soil salinity was directly related to fruit yield reduction, but not to stover yield which was not affected by salinity. The salt tolerance during germination was similar to subsequent growth in the salinity range of this experiment.Contribution from the Agricultural Research Organization. The Volcani Center, Bet Dagan, Israel 1972. Series, No. 2225-E.Contribution from the Agricultural Research Organization. The Volcani Center, Bet Dagan, Israel 1972. Series, No. 2225-E.     

Seasonal changes in symbiotic nitrogen fixation and haemoglobin content in nodules of peanuts

Summary Seasonal fluctuations of haemoglobin (Hb) concentration in nodules and the percentage of nitrogen (N) in leaflets of rhizobium-inoculated peanuts from various planting dates, were studied under field conditions.In peanuts planted in the usual season (April, May), no correlation was found between the N and Hb concentrations during the early stages of peanut growth; however, there was a very significant correlation at later periods of plant growth. With July (out-of-season) planting there was no correlation between the Hb and N concentrations at any time.The possibility of evaluating the atmospheric nitrogen (N₂) fixation rate of peanut plants under field conditions by means of Hb and N determinations was studied.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. 1972 Series, no. 2213-E.     

Using forage crops to reduce nitrate accumulation in hula peat soils

Summary A two-year field experiment was made of growing Rhodes grass and alfalfa on peat soil of the Hula Valley, where high nitrate accumulation occurs under row crops or plantless soil and leads to the danger of contamination of Lake Kinneret. The aime of the investigation was to use these perennial high-nitrogen-consumer crops to prevent the nitrate accumulation in the peat soil. The results showed a drastic decrease in soil N-NO₃ under both species in two irrigation systems obtaining high dry matter yields with high plant nitrogen content without the use of any nitrogen fertilizer. Contribution from The Volcani Center, Agricultural Research Organization, Bet Dagan, Israel. 1977 series, no.263-E.     

THE NUMBER OF ASSESSORS REQUIRED FOR TASTE PANELS

Consideration of the difference in taste between two samplesas a variable leads to estimates of variance. Any minimum differencein taste scores can be detected if a large enough number ofassessors is used. ^* Contribution from the Agricultural Research Organization,The Volcani Center, Bet Dagan, Israel. 1976 Series, No. 271-E.     

Effect of red and far-red illuminations at the end of short days and their interaction with night-break illuminations, on flowering of Chrysanthemum morifolium plants

Flowering of chrysanthemum plants grown for 8 hr in sunlightwas delayed by 20 min of FR given prior to 16 hr dark periods.These FR illuminations increased the inhibition caused by thresholdamounts of night-break illuminations. On the other hand, 20min of R at the start of the dark period alleviated some ofthe inhibitory effects of the threshold of night-break illuminations. ¹Contribution from The Volcani Center, Agricultural ResearchOrganization, Bet Dagan, Israel, 1972 Series No. 2184 E. (Received August 26, 1972; )     

Occurrence of nitrite reductase in citrus leaves

Evidence is presented for the presence of nitrite reductasein citrus leaves. The enzyme has a Km for nitrite of 45 mu andis inhibited by cyanide. However, unlike citrus nitrate reductase(l), it is probably not a metalloflavo protein, although itmay be related to iron. In addition to the enzymatic nitrite reduction, non-enzymaticnitrite reduction was present in citrus leaf preparations. Underin vivo assay conditions nitrite reduction in one-month-oldleaves was not inhibited by cyanide, in contrast with three-month-oldleaves in which nitrite reduction was almost completely inhibited.Thus it appears that in very young citrus leaves most of thenitrite reduction is non-enzymatic. ¹ Contribution from The Volcani Center, Agricultural ResearchOrganization, P. O. B. 6, Bet Dagan, Israel. Series 1972.........2256AE. (Received November 28, 1972; )     

Relation between catalase activity and fungal survival in lemon fruit infected by Phytophthora citrophthora

In lemon fruit inoculated with Phytophthora citrophthora, a continuous increase in H₂O₂ during the incubation and rot development periods was found at the infection site; seven to ten days after inoculation of the fungus, the mycelium and fruit cells were dead. The suggestion is made that the increase in H₂O₂ may be related to the decrease in catalase activity and be responsible for the death of the fungus and fruit cells.The effect of different concentrations of peroxide on the fungus in-vitro was tested.Contribution from the Volcani Center, Agricultural Research Organisation, Bet Dagan, Israel. 1974 Series, No. 104-E. Division of fruit and Vegetable Storage, Bet Dagan 50 200, Israel/     

Root and microbial biomass dynamics under the canopy of the desert shrub Zygophyllum dumosum

Summary A study was done to evaluate the influence of soil moisture and rainfall on root and microbial biomass production under the canopy of the desert shrub Zygophyllum dumosum. During the study period the root biomass production increased following the early rains but subsequently declined, remaining fairly constant thoroughout the season. In contrast microbial biomass and soil organic matter increased during the rainy season and declined with the onset of the dry summer period. Based on our results we suggest that the moisture event and not the amount and the organic matter content regulate root and microbial biomass production at the 0 to 10 cm soil layer.Contribution of the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. paper no. 2617-E, 1989 series     

Studies on fertilization of field-grown irrigated alfalfa

Alfalfa (Medicago sativa L.) yields of 20–25 ton/ha are obtainable in a Mediterranean climate, with 8–9 harvests each year. These high yields demand a large supply of potassium from the soil. Plant uptake of potassium reached 540 kg K ha, the majority being derived from the exchangeable form. A safety level of 2.5% K in the whole plant is needed to prevent yield declines. Fertilization with potassium chloride gave higher yields than with potassium sulfate. Splitting the K application over period of two cuts is recommended for sandy loam soils with a low cation exchange capacity.Contribution from the Agricultura Research Organization, The Volcani Center, Bet Dagan, Israel. 1975 Series, No.186-E.     

Estimation of available potassium for cotton by soil analysis

Measurements of exchangeable K, percentage of exchangeable K of the total exchange capacity (EPP), K extracted in a CaCl₂ solution, and the change in free-energy of exchange of K for Ca+Mg (F), were compared as methods for estimation of available K in soil for growing irrigated cotton. A significant correlation was found between each of the methods and the response to K fertilizer. The different methods are discussed; the advantages of extraction with CaCl₂ solution are that it reflects the change in free energy and is easy to operate. For sandy soils, it is suggested that determination of exchangeable K be added.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. 1975 Series, No. 202-E Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. 1975 Series, No. 202-E     

Effect of gibberellic acid on flowering and the thebaine yield of different clones of Papaver bracteatum

Two foliar applications of gibberellic acid (GA₃, 250 mg l^–1) enhanced the flowering in various clones of Papaver bracteatum. The most pronounced effects were obtained in late flowering clones in which GA₃ increased significantly the number and weight of the capsules and thebaine yield per plant.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel, No. 1267-E, 1984 series.     

Haemoglobin determination and its value as an early indication of peanut rhizobium efficiency

Summary A modified procedure based on the cyanmethaemoglobin method for haemoglobin (Hb) determination in peanut nodules is described. It gave reliable results when tested on peanuts at all stages of vegetative growth, including when the green pigment was present in the nodules. It was shown that early (32–34 days after planting) determination of Hb in nodules of peanuts grown in a greenhouse under bacteriologically controlled conditions can be taken as a measure of the nitrogen-fixing ability of peanut Rhizobia and thus much of the time and greenhouse facilities usually required for strain screening may be conserved. Early determination of nitrogen concentration in leaflets of peanuts proved to be also a useful measure of Rhizobium efficiency, but less sensitive than the early determination of nodule haemoglobin. Contribution from The Volcani Institute of Agricultural Research (N.U.I.A.), Bet Dagan, Israel. 1969 Series, No.1461-E.     

The effect of growth hormones on bananas: A review

An attempt has been made to compile the knowledge from the available literature. The growth regulators reviewed include auxins, gibberellins, cytokinins, ethephon, CCC, Alar, ABA, morphactin and TIBA. None of them is used routinely. The chlorophenoxy and naphthalene compounds are definitely harmful. All others discussed are worthy of further study.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 593-E, 1982 series.     

Improved efficiency of plant regeneration from protoplasts of eggplant Solanum melongena L.

Eggplant (Solanum melongena L.) mesophyll protoplasts were obtained from in vitro growing plants of line 410 and cv. Classic. Relatively high (15%) plating efficiency was achieved using petri dishes with alternate quadrants containing reservoir medium (R medium + 1% activated charcoal) and culture medium. Shoot regeneration occurred within 6 weeks following initiation of protoplast culture.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan Israel, No. 1164-E, 1984 Series.     

COMPARISON OF DISCRIMINATION ABILITY BETWEEN TASTE PANEL ASSESSORS

Expanded tables are presented for the selection of assessorsfor taste panels. These tables may also be used for comparingthe assessors' discrimination ability, after the panel sessionshave been completed. ^*Contribution from the Agricultural Research Organization, TheVolcani Center, Bet Dagan, Israel. 1976 Series, No. 159-E.     

Somatic hybridization in Petunia

Summary Two types of cytoplasmic hybrids were obtained by protoplast fusion. These contained either one or the other original parental nucleus and heteroplasmon, a mix of plasmons inducing cytoplasmic male sterility and fertility. In subsequent generations, following selfing, stable male sterile and male fertile lines segregated from single fertile cytoplasmic hybrid plants. These data demonstrated the existence of a heteroplasmic state in the somatic hybrids and the occurrence of cytoplasmic segregation of the heteroplasmon into homoplasmons following the first and the second meiotic cycles.Contribution from the Agricultural Research Organization, The Volcani Center, Division of Plant Genetics & Breeding, Bet Dagan, Israel. No. 275-E, 1979 series     

Phosphorus in the soil-plant-animal ecosystem

Summary A compartmental model of phosphorus in soil-plant-animal ecosystem is described. It consists of 17 compartments, five in soil, six in plant, three in above ground fauna and three in soil organisms and microorganisms. Common amounts and rates of turnover in each of these compartments is presented. Though the total amount of P in the ecosystem is large, only a very small part of it is being cycled, and presented data show that removal of P from an agricultural pastoral ecosystem is very slight. Most of the available phosphorus which is absorbed by plant roots is gradually fixed in forms of long-range unavailability, both by plants and by animals. This process of biological fixation is counterbalanced mainly by the activity of soil microorganisms. Quantities of input-output of P in intensive pastoral ecosystems are also presented, and some agronomical and ecological implications are considered. The manipulation of soil microorganisms and change towards more desirable P releasing strains or species may decrease need of fertilization, lower the risk of eutrophication and enhance productivity of such ecosystems. Such manipulations, however, can be achieved only after appropriate research.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. 1976 Series No. 160-EThis paper was presented as a lecture at the first N.H. Tadmor Memorial Meeting, December 1974, Jerusalem, Israel     

Phosphorus and pH relationships in an andic soil with surface and incorporated organic amendments

Muskmelon seedlings were grown hydroponically in a greenhouse and starved of nitrogen and/or phosphorus for 4 weeks. They were then transferred to an optimal N and P regime or to the opposite stress for an additional 3-week period. Nitrogen stress reduced markedly N, Ca, and chlorophyll contents of leaves and stems, but increased P content. Phosphorus stress reduced significantly P and K concentrations in stems and leaves but did not affect markedly chlorophyll content and did not result in N accumulation. Both stresses reduced significantly the area of the first leaf mainly by adversely affecting cell division. Repair of N and P concentrations in deficient seedlings by transfer to the optimal nutrition regime was more rapid in N- than in P-stressed seedlings.Contribution from the Agricultural Research Organization. The Volcani Center, Bet Dagan, Israel, No. 2351-E, 1988 series, Pl. Soil.     

Evaluation of isozyme systems in Citrus to facilitate identification of fusion products

Summary Ten isozymes were analyzed in nucellar calli of nine Citrus species and cultivars and roots of the corresponding apomictic seedlings. The zymograms obtained can be divided into three groups: a) isozyme patterns similar in both calli and roots, b) isozyme patterns similar in calli but variable in roots, and c) isozyme patterns variable in both calli and roots. Analysis of these ten isozyme systems may facilitate identification of fusion products in Citrus.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 354-E, 1982 series     

Studies in clover soil sickness

Summary The nature of clover soil sickness (CSS) was studied in pot experiments using soils on which berseem had been grown for three, two, one and no years. Both the distribution of CSS with soil depth, and the effect of soil sterilization by dry heat and methyl bromide on the manifestation of CSS in berseem and Persian clover, were studied.CSS factors disappeared in berseem following heat sterilization and in both Persian clover and berseem following methyl bromide treatment.The CSS phenomenon was found in berseem grown on soil from the 0–20-cm and 60–80-cm soil layers of three-year berseem plots. The effect of upper layer-CSS was discernible only after the first harvest, while that of the deep layer one affected growth drastically immediately after germination. Other possible CSS factors are suggested.5012 plant and soilContribution from The Volcani Institute of Agricultural Research, Bet Dagan, Israel, 1971 Series, No. 1884-E. This work was financed by Grant F. G.-IS-222 from the U.S. Dept. Agriculture, under P.L. 480.