Water Culture Experiments Research Articles

Cadmium absorption by rice plants

Abstract Cadmium absorption by rice plants was examined by means of water culture experiments with l15mCd. The time course of the cadmium absorption by young plants was found to consist of two phases: one was the initial rapid phase and the other was the succeeding rather steady phase with smaller absorption rate. Cadmium distribution within rice plants were related to the phases of absorption. About 60% of 115mCd absorbed in the initial phase was released (exchanged) when soaked in 10 ppm cadmium solution. Incorporation of cadmium occurred in killed roots also. Rice plants absorbed cadmium actively when cadmium concentration in culture solution was low, while when it was high the mode of absorption implied that rice roots might actively depress the income of cadmium. Relationship between the rate of cadmium absorption by excised roots and the cadmium concentration in culture solution showed a kind of dual pattern.

Sensitivity of Sesame to Various Salts1

AbstractPlants tolerate widely varying proportions of salts in the root media but nutritional imbalances and specific ion toxicities may occur if one salt predominates under saline conditions.The relative sensitivity of sesame (Sesamum indicum L.) to various ions and the nature of the specific ion toxicities were studied in water culture experiments. At 0.10 MPa osmotic pressure, NaNO3, NaCl, Na2SO4, and CaCl2 reduced the yield (shoot + pods) of Sesame by about 15, 26, 33, and 65%, respectively. At 0.20 MPa, Ca(NO3)2 was more injurious than NaCl or any combination of the two salts.Chemical analyses indicated that sesame roots did not accumulate C1, Na, and Ca readily, since the accumulation factors for these ions were near or less than 1. However, leaves accumulated these ions to a considerable extent. Leaf Na concentrations of 162 µmol/g fresh wt were associated with necrosis but no evidence of C1 toxicity was noted. Calcium‐induced necrosis seemed indirect, possibly a consequence of decreased Mg concentration. Ion concentration gradients indicated a specific accnmulation of Na in the stem. This retention was greater, and less Na reached the leaves, when the anion was C1 than when it was SO4, a difference that may explain the greater sensitivity of sesame to Na2SO4 than to NaCl.The high sensitivity of sesame to single‐salt salination emphasizes the importance of using salt mixtures in salt tolerance studies. At extreme Na‐Ca ratios, ionic imbalance predominates and growth suppression exceeds that due to osmotic stress.

The role of macronutrients for cabbage-head formation

Abstract A water culture experiment was conducted to interpret how three major nutrients (N, P, K) contribute to cabbage-head fonnation when they are supplied in a different amount and at different growth stages. The critical N, P, and K contents in the outer leaves which resulted in a 50% decrease in the cabbage-head yield due to each deficiency were 1.3, 0.1. and 0.3% on a dry basis, respectively. The longer the period of each nutrient supply, the higher was the cabbage-head yield. The contribution of nitrogen per unit weight to cabbage-head fonnation was the highest at the third growth stage (i.e. early cabbage-head development phase) and that of phosphorus and potassium at the first growth stage (i.e. outer-leaf expansion phase) among the four growth stages. The nitrogen supplied for 20 days at any growth stage of the four growth stages did not produce an ordinary cabbage-bead but the phosphorus at the second growth stage (i.e. outerleaf development phase) produced a big cabbage-head comparable to that of the plants receiving phosphorus during the whole growth stage. The potassium supplied at the first or the second growth stage produced a small cabbage-bead but failed to produce any cabbage-head at the later growth stages.

Tuberization in potato plants as affected by applications of nitrogen to the roots and leaves

Tuberization can be prevented in water culture experiments with continuous nitrogen supply via the roots. Interruption of the nitrogen supply via the roots induces tuberization; simultaneous sprayings of the leaves with urea cannot delay or prevent tuberization. Nitrogen analyses show that there is no correlation between nitrogen content of the plants and tuberization. The results are discussed in terms of hormonal changes within the roots and shoots caused by the differences in nitrogen nutritional status of the roots.

Effect of Excessive Manganese Supply on Uptake and Translocation of Calcium in Bean Plants (Phaseolus vulgaris L.)

In short- and long-term water culture experiments an excessive supply of manganese inhibited the calcium translocation into the leaves of bean plants (Phaseolus vulgaris L.). This inhibition was not based on a reduction of the transpiration rate, nor could it be explained by a simple cation competition for binding sites. Particularly in fast growing leaf tissue, the inhibition of calcium translocation was much more pronounced than that of other cations, for example potassium. Inhibited calcium translocation resulted in typical symptoms of calcium deficiency (e.g., «crinkle leaf») in the shoot apices and youngest leaves at toxic levels of manganese. Excessive manganese supply caused the cation exchange capacity in the leaf tissue to be distinctly reduced, and the calcium uptake into the AFS of isolated leaf segments from leaves showing manganese toxicity was lower. It is concluded that under conditions of manganese toxicity the IAA-oxidase-activity is increased with a concomitant decrease in auxin level. The lower auxin level causes inhibition of cell wall expansion and, in turn, a reduction in formation of new negative binding sites and thus decreased calcium translocation into this tissue.

Nitrogen Nutrition and Cytokinin Activity in Solanum tuberosum

AbstractIn water culture experiments with potato plants (Solanum tuberosum L. cv. Ostara), the influence of continuous nitrogen nutrition (constant supply of NO3−) and discontinuous nitrogen nutrition (interruption of NO3− supply, i. e., nitrogen withdrawal for 6 days) on the endogeneous cytokinin level in the roots, shoots and exudate of decapitated plants was studied. Harvests took place at intervals of 3 days. The chlorophyll formation test (cucumber cotyledons) and soya callus test were used to determine the cytokinin activity.With continuous nitrogen, the cytokinin activity decreased slightly with time in both roots and shoots but rose in the exudate. With discontinuous nitrogen, the nitrogen withdrawal led to a temporary, pronounced increase in cytokinin activity in the roots; at the same time, the cytokinin activity in the exudate decreased sharply. It is assumed that this temporary increase in cytokinin activity in the roots is a reflection of increased meristem activity in the roots. In the shoots, the cytokinin activity decreased during the nitrogen withdrawal period. These nitrogen‐induced changes in cytokinin activity in the roots and shoots of potato should presumably have an important influence on the physiological age of the shoot, with all its consequences in the further development of the plant. Zeatin riboside was likely the main cytokinin component involved.

Symptome von Mangan‐Überschuß bei Bohnen (Phaseolus vulgaris)

Symptoms of manganese toxicity in beans (Phaseolus vulgaris L)In water culture experiments with bush bean plants (Phaseolus vulgaris L. var. „Red Kidney”︁) the macro‐ and micro‐symptoms of manganese toxicity had been studied.Typical symptoms of Mn toxicity are small distinct blackish‐brown spots, first at the older leaves and at more severe toxicity also at the petals and stems. Using the autoradiographic technique on 54Mn‐distribution and comparing this with corresponding light microscopic studies it could be demonstrated that the blackish‐brown spots in the leaves resemble Mn‐precipitations.These precipitations are Mn‐compounds of higher oxidated form and are primarily localized in the walls of cells in vicinity of the vessels. The extend to which these precipitations occur is not only a function of the Mn‐content of the leaves but also of their age. At comparable Mn‐content the extend of the precipitation increases with the leaf age.As secondary symptom of Mn‐toxicity under certain conditions (presence of silicon e.g.) induced Fe deficiency (chlorosis of the youngest leaves) and Ca deficiency („crinkle leaf”︁) may occur.It is assumed that the process of Mn precipitation within the leaves is enzymatically regulated. The severe reduction in the growth of leaf blades at Mn toxicity is presumably related to an interference with the growth hormon balance.

Einfluß von Silizium auf den Bindungszustand von Mangan im Blattgewebe von Bohnen (Phaseolus vulgaris)

Effect of silicon on the chemical state of manganese in bean leaf tissue (Phaseolus vulgaris L.)In water culture experiments with bean plants the effect of different manganese supply and of silicon on the chemical state of manganese in the leaf tissue has been studied. Water, KCl, EDTA and methanol have been used for extraction.Water extracted up to 80% of the total manganese from previously frozen or freeze dried leaf tissue. This water soluble fraction of manganese showed a positive correlation with manganese supply and leaf age. Silicon had no effect on the manganese extractable by water, KCl or EDTA.The high proportion of manganese in the water extract is probably the result of manganese oxides (MnO2?) being dissolved during extraction by organic cell constituents e.g. organic acids. Therefore, in vivo less manganese is water soluble than the amount extractable with water.In contrast to water, methanol extrated less than 10% of the total manganese. Silicon supplied in the culture solution doubled the amount of manganese extracted from the leaves by methanol. This result suggest that by affecting the compartmentation of manganese silicon increases the soluble manganese in vivo, which could partly explain the increase in manganese tolerance of the leaf tissue in presence of silicon.

Wirkung von 2,3,5-Trijodbenzoesaure (TIBA) auf den Calcium-transportund die Kationenaustauschkapazität in Sonnenblumen

In water culture experiments with sunflower, a single spraying of the shoot with TIBA(100 ppm) induced growth depression and calcium deficiency symptoms within 8-10 days, and led finally to necrosis of the shoot apex. Simultaneous spraying with CaSO4 twice a day prevented this induced calcium deficiency and nearly overcame the TIBA effect on growth. TIBA only inhibited translocation of calcium into the shoot apex, but not that of potassium,magnesium or phosphate. Particularly calcium translocation from the petioles into the blades of the youngest leaves was inhibited by TIBA. TIBA lowered the transpiration rate of the fully developed leaves only but not of theyounger ones and caused insufficient formation of sclerenchymatic tissue in the lower part of the stem. The differentiation of the vascular strands in the upper stem and in the youngest leaves, however, was hardly influenced by TIBA. TIBA decreased significantly the cation exchange capacity (CEC) in the upper part ofthe stem, especially in the apical bud and the youngest leaves. Much less calcium but more potassium was translocated into those parts with lowered CEC. The results indicate a connection between the TIBA-induced inhibition of calcium translocationinto the shoot apex and the inhibitory effect of TIBA in IES transport. This inhibition of IES transport could lead to a lower activity of the IES-stimulated proton efflux pump in the elongation zones of the shoot apex. This, in turn, could cause a decrease in formation of new exchange sites (i.e. CEC) in these regions and therefore a lower attraction of the shoot apex for calcium.

Effects of pH and Al on the Growth and Chemical Composition of Cicer Milkvetch1

AbstractCicer milkvetch (Astragalus cicer L.) is one of several legume species which has been used for the stabilization of Massachusetts roadsides. In this study the following treatments were combined in soil and water culture experiments: pH levels 4.2, 5.4, and 6.3, and aluminum levels of 0, 2.5, and 5.0 ppm added to soil, 0, 5, and 15 ppm Al in water. The objective was to examine the interactions among soil treatments, factors of acid soil infertility, and the chemical composition and growth of cicer milkvetch (‘Lutana’). Dry weights and root penetration doubled in response to soil pH 5.4. At soil pH 6.3 manganese in the soil and in the plant tissue rose to high levels while dry weights and root penetration declined. On the other hand, dry weight of tops and root elongation were significantly greater at pH 5.4 and 6.3 than at pH 4.2 in water culture. Soil Al treatments were positively related to water soluble soil P and soil Mn availability. Nutrient solution Al additions significantly enhanced Al in tops. Also, the 5 ppm Al level significantly stimulated root elongation, while 15 ppm Al was related to reduced elongation. Dry weights were not significantly affected by Al treatments in soil or water culture. The apparent acid tolerance of cicer milkvetch, plus the buffering capacity of this soil, and the sufficient supply of P at all treatments in water culture apparently diminished the A1 treatment effects. Cicer milkvetch growth is enhanced by CaCO3 application of at least 1,750 ppm to this soil for these reasons: percent Ca and P of tops rose above critical levels, while excess soil Mn and Al levels declined, allowing enhanced root penetration of the soil.

Einfluß exogener und endogener Faktoren auf den Calciumgehalt von Paprika‐ und Bohnenfrüchten

Effect of external and internal factors on the calcium content of paprika and bean fruitsIn water culture experiments with paprika and bean plants the effect of Ca supply, transpiration and growth rate on the Ca content of the fruits has been studied.A 10‐fold increase in Ca supply only slightly increased the Ca content. The Ca content of the paprika fruits was increased considerably at high transpiration rates of either the whole shoot or the single fruit. High transpiration also increased the Mg content but had no effect on the K content. In bean high transpiration rates only increased the Ca content in the early stages of fruit development.The ratio of Ca translocation versus water loss by transpiration sharply declined during fruit growth in both species. In paprika the highest ratio (μg Ca/ml) in the fruits corresponded with the ratio in the leaves. In bean fruits, however, this ratio distinctly exceeded that of fully developed leaves.At high transpiration rates of the shoot 20% of the Ca (45Ca) injected into the fruit were translocated out of the fruit. At low transpiration rates of the shoot the corresponding value was below 1%.Most of all the growth rate of the fruits affected the Ca content. With increasing growth rate the Ca transport into the fruits was hardly altered which in turn led to a sharp decrease of the Ca content per unit dry weight.The results support the idea of the Ca transport into the fruit via the xylem. This Ca transport — i.e. also the Ca content of the fruit — is regulated and is also to be influenced by direct or indirect alterations of the water transport in the xylem.

Response of Three Semidwarf Mexican Wheats to Different Aeration Conditions in the Rooting Medium at a Constant Salinity Level

AbstractThe response of three newly developed Mexican wheat (Triticum aestivum L.) varieties, Nuri 70, Inia 66, and Siete Cerros 66, to low oxygen at constant salinity of −4 bars in the rooting medium was tested in a water culture experiment under growth chamber conditions. Oxygen concentrations in solution were maintained at 1.5, 5.2, and 7.6 ppm by bubbling gas mixtures containing 0, 12, and 21% oxygen, respectively.All varieties were affected by low oxygen at high salinity, but Inia 66 had the greatest adaptability to low oxygen concentrations in the root zone. Oxygen concentrations of 0% in the aerating gas decreased plant dry‐matter production by 50%. Plant length was not affected, but the ability to produce tillers was inhibited. This same oxygen concentration reduced transpiration by 54, 66, and 65% for Inia 66, Siete Cerros 66, and Nuri 70. Root porosities increased with each decrease in oxygen content, with Inia 66 showing the largest increase. In general, for other measured plant characteristics, no significant differences were noted between plants grown at 12% oxygen and those at 21%.

Auswirkungen von NaCl und Na2 SO4 auf Substanzbildung, Mineralstoffgehalt und Inhaltsstoffe bei Spinat und Salat

Effect of NaCl and Na2SO4 on dry matter production, mineral content and organic compounds of spinach and lettuce.In water culture experiments the effect of 2,5 meq and 25 meq NaCl and Na2SO4 respectively on dry matter production and content of mineral elements, chloroplasts pigments and carbohydrates in lettuce (salt sensitive) and spinach (salt tolerant) has been studied.With increasing Na‐supply the dry matter production was decreased in lettuce and increased in spinach. With increasing Na‐supply in both species the content of K, Mg and Ca in the leaves decreased. This decrease was more pronounced with sulfate as accompanying anion (Na2SO4) and induced already deficiency in Ca and Mg. This induced deficiency of Mg was reflected especially in lettuce in lower contents of chloroplasts pigments.In both plant species there was no effect of the Na salt treatments on the content of phosphorus or nitrogen in roots or leaves.The carbohydrate content in both species was strongly affected by the Na salt treatments. Irrespectively of the accompanying anion this effect occured already at the low Na supply and before the dry matter production was influenced. In leaves and roots of lettuce the contents of glucose, fructose and sucrose was considerably decreased; this decrease was less expressed in the starch content. In spinach the Na supply only decreased the carbohydrate content in the roots whereas in the leaves especially the sucrose content was increased. This different effect of Na on carbohydrate content in spinach and lettuce could be an indication of different action of Na on carbohydrate metabolism, namely inhibited synthesis in lettuce and inhibited translocation in spinach.The results demonstrate that in studies on the effect of increasing Na salt concentrations besides the osmotic effects also the ion specific effects have to be carfully considered. These ion specific effects are competition of Na+ with other cations during uptake and the influence of Na on the cell metabolism, especially on the pathway of carbohydrates.The authors thanks Mrs. Hwie Juen Tjandraatmadja for her engaged help in various laboratory works.

Gibberellic Acid Induced Changes in the Ultrastructure of Chloroplasts and the Content of Chlorophyll in Leaves of Dwarf Maize (Zea mays L.)

Summary Water culture experiments with a complete nutrient solution were conducted to investigate the effect of GA 3 -treatment on the ultrastructure and the pigment content in the 3rd leaf blade of dwarf maize. Tall maize was also included for comparison. It was found that dwarfism in maize was nearly without effect on the ultrastructure and the pigment content of chloroplasts. GA 3 induced an absolute decrease in the total chlorophyll content in the leaves of dwarf plants. The ultrastructure of both mesophyll and bundle sheath chloroplasts of GA 3 -treated dwarf plants was markedly changed. In mesophyll chloroplasts, the grana and stroma thylakoids were swollen and showed a certain degree of desorientation. A great number of osmiophilic granules were scattered between the swollen thylakoids. The chloroplasts in the bundle sheath cells differed in their sensitivity to GA 3 . Some of them were deformed and quite irregular in shape and showed a great number of osmiophilic granules and large vacuoles. Other chloroplasts exhibited well-developed small grana and small starch grains. Chloroplasts with normal structure were also found. The observed effects of GA 3 -treatment on the ultrastructure of plastids are not primary effects of the growth substances. The interrelationships between GA 3 -treatment, structure of chloroplasts and calcium content will be discussed.

Studies on the Growth of Tobacco Roots : XI. Effect of root-cutting and no aeration to roots on the contents of nicotine in the whole leaves

For the purpose of finding the influence of root-cutting and no aeration treatment to roots at flowering stage on the content of nicotine in the whole leaves, experiments were conducted by using several varieties of water-cultured and field-grown tobacco. The results obtained were as follows. 1. According to the data of water-culture experiment, nicotine concentration in the leaves of Hicks and MC subjected to no aeration treatment was lower than that in the root-cut tobacco. On the other hand, the whole leaves of non-topping tobacco contained lower quantity of nicotine than those of the topped tobacco subjected to no aeration and root -cutting. 2. In Hicks variety, a close relationship was observed between the respiratory rate of whole roots and concentration and content of nicotine in the whole leaves. In MC variety, the correlation between the respiratory rate of whole roots and nicotine concentration was significant. 3. According to the data of field experiment, concentration and content of nicotine in the whole leaves of high nicotine varieties from which the adventitious roots originated from stalk base had been cut off tended to increase by lower topping, and tended to decrease by higher and non-topping. In low nicotine varieties, effect of cutting adventitious roots was not so remarkable as high nicotine varieties.

Aufnahme und Sorption von zwei‐ und dreiwertigem Eisen durch Sonnenblumenpflanzen (Heliantus annuus L.)

Uptake and adsorption of ferrous and ferric iron by sunflower plants The uptake of iron by 13 day-old sunflower seedlings in water culture experiments was studied using FeCl3, Fe-citrate and ferroammoniumsulfat (Mohr'sches Salz) in the-nutrient solution. By raising the N-, K- and Ca-content and lowering the P-content of the nutrient solution at the same time the iron content of the exudate in the FeCl3-treatment was increased up to 200 %. In the case of Fe-citrate, similar values were obtained only under aeration conditions of the nutrient medium. Application of iron as ferrous sulfate led to an increase of the iron content in the exudate and in the aerial plant parts amounting to about 200 and 400 %. respectively over that of the FeCl3 treatment. After 15 hr-uptake, most of the iron, taken up by the seedlings was in an unexchangeable form in the root system. The results give a further evidence for the peferential uptake of iron in the ferrous form.

The Ecology of Becium Homblei in Central Africa with Special Reference to Metalliferous Soils

concentrations of economically important base metals in the soil is a subject of increasing interest. Although the major contributions to the literature in this field are related to temperate zones, the Labiate species Becium homblei (De Wild.) Duvign. et Plancke has attracted some attention in the past due to its occurrence on copper-bearing soils in Central Africa. Duvigneaud (1959) and Duvigneaud & Denaeyer de Smet (1963), in their analysis of the flora of the copper-bearing soils in Katanga, place B. homblei in a group of plants which they call the 'cuprophyles'. This group is characterized by species which have a tendency to accumulate copper in soils lightly enriched with that metal, and which can serve as botanical indicators of copper. Cannon (1960) and Malyuga (1964) state that B. homblei (Ocimum homblei) was responsible for the discovery of copper deposits in Zambia and Rhodesia, where the plant was believed to be confined to soils with over 100 ppm copper. Horscroft (in Mendelsohn 1961) states that Becium homblei contains an abnormally high amount of copper, and in a water culture experiment he found that the seeds would germinate only in solutions containing 50-600 ppm copper. For some time B. homblei was believed to be an endemic on cupriferous ground in Rhodesia (Wild & Heyting 1966), where it was thought to be a physiological ecotype

Further experiments on the acid grassSetaria sphacelata

Field trials carried out in 1963 and 1964 have confirmed the ammonia-acidity relationship in the grassSetaria sphacelata. The addition of nitrogenous fertilisers enhanced ammonia accumulation in the grass but not titratable acidity. Sand- and water-culture experiments confirmed the essentially acidic nature ofS. sphacelata and the presence of a relatively highly dissociated acid which was found to be oxalic acid. In these experiments ammonia accumulated inS. sphacelata even when nitrogen was supplied as nitrate alone. Darkening the plants for seven days during growth in the field led to a marked accumulation of ammonia inS. sphacelata particularly when covered during early growth. From the evidence obtained it is concluded thatS. sphacelata is essentially an acid grass and that ammonia accumulation is a consequence of this. The mechanism proposed is that part of the ammonia in the plant, whether derived from direct uptake, nitrate reduction or decomposition (following darkening) of organic nitrogenous compounds, is present as ammonium oxalate. Since plant protoplasts are relatively impermeable to ions ammonium accumulates in the grass. The subsequent decline in concentration in the plant, with increasing maturity, is ascribed to the increase in structural carbohydrates and lignin (a dilution effect) and possible slow utilisation of the ammonium.

Acid Metabolism in Atriplex I. Regulation of Oxalate Synthesis by the Apparent Excess Cation Absorption in Leaf Tissue

The leaves of AtripZe:c and eight related genera of the Chenopodiaceae from semi-arid Australia oontained high levels of oxalate. Most of the oxalate was in the soluble form and was correlated with high cation content generally rather than with calcium level. In water-culture experiments calcium absorption and oxalate synthesis varied independently.

Metabolism of nitrate- and ammonium-nitrogen absorbed from ammonium nitrate and ammonium sulfate in the tobacco plant

Abstract In water culture experiments with tobacco plants, ammonium nitrate has been generally used as a nitrogen source. In a comparison among various nitrogen sources for water cultured tobacco, better growth has been obtained with ammonium nitrate than with sodium nitrate and ammonium sulfate (1). It has been shown that both ammonium- and nitrate-nitrogen are simultaneously absorbed by the tobacco plant from ammonium nitrate (2). It has been also apparent that physiological toxicity developed when ammonium-nitrogen was absorbed from ammonium sulfate. It has been considered that this toxicity developed by the abnormal metabolism of ammonium-nitrogen in the plant. No toxicity appears to develop when ammonium-nitrogen is absorbed from ammonium nitrate. In the present paper, the metabolism of ammonium- and nitrate-nitrogen absorbed from ammonium nitrate and ammonium sulfate in the tobacco plant was investigated.