摘要:

Aubergine eggplant plants(Solanum melongenaL.) were grown under greenhouse conditions with nitrogen and phosphorus fertilization individually, or both, and with a large amount of organic matter and CaSO4in the soil superficie. The irrigation water was strongly brackish. In the plants, nitrate and phosphate showed an obvious mobility, whereas chloride and sulfate were relatively immobile. Cations in the form of potassium and ammonium were highly mobile, during the growth cycle, whereas the other cations tested were immobile. Translocation of anions was weak with little change in concentration throughout the growth cycle, whereas cations showed marked variations in different stages due to the influence of NH4+and K+mobilization. The accumulation of cations was offset by hydrogen extrusion to maintain foliar pH within physiological limits. Sharp changes in pH were buffered by the effect of citric acid as an organic anion, which absorbed the excess positive charge. Alterations in cations increased the formation of organic acids, a process clearly dependent on the stage of the growth cycle. The finding of this study is that behavior of ion balances remained constant regardless of the dose of fertilizer applied, but changed in response to the stage of the growth cycle.

ISSN:0190-4167    

DOI:10.1080/01904169509364987

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Ion relations, water content, leaf water potential, and osmotic adjustment were determined for cultivated barley (cv Harrington) and wild barley grown under mixed sulphate (SO4) salts with varied calcium (Ca) supply using a hydroponic system. Salinity induced significant increases of leaf, stem and root sodium (Na) concentrations in both species. Salt‐stressed wild barley roots accumulated more Na than shoots, and transport of Na from roots to shoots was low compared to Harrington. Cultivated barley had lower Ca concentrations than wild barley, especially in the low Ca salt treatment. Although potassium (K/Na) and Ca/Na ratios were higher in control wild barley plants than in Harrington, they declined under salt stress, irrespective of Ca supply. Major osmotica in wild barley leaves were K, sugars, organic acids, and quaternary ammonium compounds, while in Harrington they were cations, including Na, K and Mg, and anions such as phosphate (PO4) and SO4. Wild barley maintained better water status than Harrington under low Ca salt treatment. Supplemental Ca improved water status more in Harrington than in wild barley. Lack of osmotic adjustment to salinity in wild barley apparently resulted from its ion exclusion. Low Ca salt treatment caused Ca deficiency, Na toxicity, and loss of turgor in Harrington. In the high Ca salt treatment, Harrington had improved water and ion relations, as well as positive turgor.

ISSN:0190-4167    

DOI:10.1080/01904169509364988

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Three‐week‐old nodulated faba bean plants were subjected to two levels of water stress (0.5 and 0.25 field capacity; soil water content of 20 and 10%) for five weeks. Half of the stressed plants was treated with potassium chloride (KC1) at 10 (K1) and 150 mg (K2)/kg soil at the beginning of water deficit. Nodulation was examined and some nodule activities were assayed. Nodulation, nitrogenase activity, total nitrogen (N), and dry matter yield were significantly decreased by increasing stress but were significantly higher with the two levels of potassium (K) supply. Leghaemoglobin and protein contents of cytosol as well as nodule protease and invertase were severely depressed by drought stress. Soluble carbohydrate contents of nodules, however, was significantly increased. Protein and leghaemoglobin contents and enzyme activities were greater with K fertilization but less soluble carbohydrate was accumulated. The results indicate that K supply, particularly at the 150 mg/kg soil level, increased faba bean resistance to water stress.

ISSN:0190-4167    

DOI:10.1080/01904169509364989

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The effect of three levels of salinity (2.0,4.0, and 8.0 mS/cm) on growth and ion composition of tomato and cucumber seedlings was examined with and without addition of 7.4 meq/L calcium chloriode (CaCl2). The corresponding sodium/calcium (Na/Ca) ratio of the irrigation solution were 4.0 and 1.8 at salinity level 4.0 mS/cm, and 12 and 4.8 at salinity level 8.0 mS/cm. Seedlings growth of tomato and cucumber was generally reduced with increasing salinity level. Cucumber was more salt‐sensitive than tomato. Shoot and root dry weight of cucumber was increased by decreasing Na/Ca ratio at 4.0 mS/cm salinity. Sodium and chloride (Cl) accumulation was increased and Ca was decreased in salinized plants. Reducing Na/Ca ratio under saline condition reduce the accumulation of Na in tomato roots. The effect of salinity on the uptake of nitrogen (N), phosphorus (P), potassium (K), Na, Ca, chloride (Cl), iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu) in the root and shoot was also determined.

ISSN:0190-4167    

DOI:10.1080/01904169509364990

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The accumulation of germanium (Ge) by barley (Hordeum vulgarecv. ‘Arivat') grown at various Ge and pH levels was investigated because Ge is an industrially important metal and bioaccumulation of Ge is a potentially useful means of concentrating this trace metal. Six‐day‐old barley seedlings were grown in perlite and nutrient solution adjusted to a pH of 4.5, 6.0, or 7.5 supplemented with 20, 40,60, or 80 μM Ge for seven days. The plants were divided into roots and shoots after harvesting; the dry weight and Ge content of the individual organs were measured, as was the peroxidase activity in the distal 1 cm of the primary leaves. Barley seedlings accumulated Ge in the roots and shoots; the shoots accumulated Ge linearly as medium Ge concentration increased. The dry weight of the organs was not affected, although necrosis was observed in the primary leaves of the seedlings treated with Ge concentrations greater than 20μM. Peroxidase activity in the primary leaves also increased as the Ge levels in the medium increased which indicated that elevated levels of Ge stimulated leaf senescence. These results demonstrate that barley plants can take up Ge and suggest that Ge is not toxic at the levels that might occur in areas where Ge is normally mined.

ISSN:0190-4167    

DOI:10.1080/01904169509364991

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The influence of temperature, irradiance, and soil humidity on the nitrogen (N) concentration in some organs, chlorophyll in the leaves, N uptake and accumulation of dry matter in plants of winter wheat was investigated. In the plants grown under equal initial N supplement but in contrasting conditions of the evironment, the correlation between concentration of total N and chlorophyll in the leaves was absent. No interrelationship was found between concentration of total N in the leaves and accumulation of N and dry matter in the whole plants. There is a close correlation between chlorophyll in the leaves, accumulation of total N, and dry matter of the whole plant. It was concluded that chlorophyll is a more stable informative parameter for the estimation of the N uptake from the soil under different growth conditions than leaf N concentration.

ISSN:0190-4167    

DOI:10.1080/01904169509364992

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Seeds of Carrizo citrange (Citrus senensis(L.) Osb. XPoncirus trifolliata(L.), Cleopatra mandarin (C.reticulataBlanco), Sour orange (C.aurantiumL.), and Rough lemon (C.Union(Bunaf.) were sown in trays, irrigated without or with enriched Carbon dioxide (CO2) (1,362 mg L‐1) and evaluated for seedling emergence, growth, and nutrient contents. Rough lemon had a faster rate and higher percent emergence than the other rootstocks. Carrizo citrange had thicker stem diameters and taller seedlings than other rootstocks. Cleopatra mandarin had the smallest seedling shoot and root weights and larger shootrroot ratios than Rough lemon and Sour orange. Carrizo citrange and Cleopatra mandarin had higher leaf chlorophyll‐a and total chlorophyll content than Rough lemon or Sour orange. Carbon dioxide enriched irrigation had no effects on emergence or seedling growth variables except lower root weight. Lower media pH (6.90 versus 5.65), attributed to CO2enriched irrigation, may have adversely affected root growth as compared to shoot characteristics. Leaf nutrient contents generally differed between rootstocks but were not affected by CO2enriched water except for higher Zn and lower Mn contents. These results indicate that citrus seedling emergence, subsequent growth and leaf nutrient content differred between rootstocks but there are no beneficial effect from CO2enriched irrigation.

ISSN:0190-4167    

DOI:10.1080/01904169509364993

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Three experiments were conducted in greenhouse under hydroponic conditions to study the response of wheat to: i) different ammonium/nitrate (NH4/NO3) ratios, ii) the application of NH4during different phenological states, and iii) the addition of calcium carbonate (CaCO3) for maximum replacement of NO3by NH4. Small amounts of NH4considerably increased yield and grain quality. The best response was observed with a 2/5 ratio NH4/NO3(meq/L). The application of small fractions of NH4 during grain fill increased production. Dry matter (DM) production decreased when large quantities of NH4were applied. However, when CaCO3was used in amounts similar to those of NH4, it was possible to neutralize the acidifing effect of reduced nitrogen (N) and to recuperate DM and grain production, thus increasing the harvest index.

ISSN:0190-4167    

DOI:10.1080/01904169509364994

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The results of four experiments were combined to determine the relationships between leaf mineral nutrients or media pH and sweetpotato transplant production. The relative number of transplants and the relative mean transplant lengths or weights were determined by comparing the values obtained with unamended aged pine sawdust, a traditional medium. These values were regressed against leaf mineral concentrations and media pH. There was no relationship between relative transplant production and leaf nitrogen (N), potassium (K), or manganese (Mn) concentrations. Compared to sufficiency ranges for nearly mature sweetpotatoes, concentrations of N and K were low and Mn was sufficient. An upper value of 1210 mg/L leaf iron (Fe) was obtained for relative mean transplant weight, but concentrations of this mineral were not associated with relative transplant numbers or relative mean transplant lengths. Leaf calcium (Ca) and magnesium (Mg) concentrations were related to all three transplant characteristics directly, or indirectly through possible effects on leaf phosphorus (P) concentration or media pH. Compared to the established sufficiency ranges for nearly mature sweetpotato plants, Ca and Mg concentrations were low, P and Fe concentrations were sufficient, and zinc (Zn) concentrations were high.

ISSN:0190-4167    

DOI:10.1080/01904169509364995

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Corn (Zea maysL.) is an important source of protein for humans and animals. Because dent corn is highly responsive to nitrogen (N) fertilization, substantial amounts of N are used for corn production. Application of N fertilizer may reduce protein quality of corn kernels through an increase in zein content. The objective of this study was to determine if corn endosperm characteristics influence the effect of N fertilization on protein quality. In 1988, six corn hybrids differing for endosperm characteristics were grown at two locations in Ohio and with two N rates, 34 and 200 kg/ha. The waxy hybrid had a greater concentration of fraction I protein than the non‐wary hybrid. These two hybrids did not differ for other fractions except fraction III at Columbus. The soft endosperm hybrid had a higher concentration of fraction I protein than the hard endosperms hybrids. Soft and hard endosperm hybrids differed for fraction II protein for the 34 kg N/ha fertilizer rate but not the 200 kg N/ha fertilizer rate. These two classes of hybrids did not differ for fraction III protein. Increasing N fertilizer increased fraction II concentration for all hybrids. Concentrations of the other two protein fractions did not respond to fertilizer rate. The increase in fraction II concentration with N fertilization may result in a decrease of protem quality and feed value. Although all hybrids responded to N fertilizer, some hybrids had bigger increases in fraction II proteins than other hybrids.

ISSN:0190-4167    

DOI:10.1080/01904169509364996

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor