Albert Ulrich

Plant Nutrient Limitations of Tundra Plant Growth

Plant growth and primary production in tundra areas can be limited by the availability of inorganic nutrients as shown by Warren-Wilson (1957), Schultz (1964), and others. More recently, attention has focused on the experimental response of tundra plants to enrichment by N (Haag, 1974) and/or P (Chapin, 1978; Chapin et al., 1975; McKendrick et al., 1978). Rigorous attempts to determine nutrient deficiencies in situ, however, have not been undertaken in tundras.

Sulfur content of alfalfa in relation to growth in filtered and unfiltered air

The effects of sulfur on plant growth have been studied intensively by many w o r k e r s a 5 6 7 9 1 4 1 5 ~ 1 2 4 2 5 2 6 272s Roots normally absorb sulfur from the soil as sulfate, although other forms of sulfur can be absorbed and utilized by plants 2 21 2~ ~s. Sulfur in the air, from natural or industrial sources, can supply some sulfur for growth to aerial portions of plants directly as SO2 8 22 23, sulfite 24 or sul, fate 26. Appreciable, but highly variable, quantities of sulfur compounds are carried by rainfall to the soil 1 4 12 16. Minor additions of sulfate to the nutrient medium increase primarily the organic-S content of the plant but with major sulfate additions sulfate-S increases much more rapidly in the plant than organic-S iv 19 2a. I t is the purpose of the present s tudy to examine these plant-sulfur interrelationships relative to growth and sulfate supply for alfalfa grown in culture solution 10 under two environmental conditions; in an unshaded greenhouse with smogfree, carbon-filtered air and in full sunlight outdoors with unfiltered air.

Critical nitrate levels for squash, cucumber and melon plants

Abstract Squash (Cucurbita pepo), cucumber (Cucumis sativus) and sweet melon (Cucumis dudain) plants were grown in sand culture with N as the variable and were harvested at the early flowering stage. The plants at this time showed a definite gradation of symptoms from severe to no deficiency of N. The tops were separated into leaves and stems. Leaves were separated into young, mature and old and then subdivided respectively into petioles and blades. The petioles were analyzed for NO3‐N. The critical NO3‐N concentration for squash, cucumber and melon on a dry basis was 1000, 2000 and 3000 ppm, respectively. A relatively high concentration of NO3‐N in the nutrient solution decreased the growth of squash and cucumber plants significantly, but had no effect on melon plants. Melon plants can tolerate relatively high concentrations of N0,‐N in the plant tissues, while squash and cucumber cannot.

Growing potato plants by the water culture technique

A water culture technique was developed for the study of the nutrient requirements of the potato plant. Tuber formation was avoided by pinching off the stolons as they developed and hence vegetative growth could be studied without the complication of abnormal tuber formation in the culture solution. The K deficiency symptoms obtained by this method were essentially the same as those observed for field grown plants.ResumenSe ha desarrollado la técnica de solución nutritiva para el estudio del requerimiento nutritivo de las plantas de papas. La formación de tubérculos se ha evitado eliminando los estolones en desarrollo, y por lo tanto el crecimiento vegetativo puede ser estudiado sin la complicación de la formación anormal de tubérculos en la solución nutritiva. Los síntomas en la deficiencia de potasio obtenida por este método eran esencialmente los mismos como aquellos observados en plantas crecidas en el campo.

Sulfur nutrition of italian ryegrass measured by growth and mineral content

SummaryThe sulfur nutrition of Italian ryegrass was studied by a nutrient solution technique. Sulfur-deficient plants were stunted and erect in appearance; upper leaves were an abnormal yellow-green. Shoot growth was affected more than root growth by changes in the amount of S supplied.The sulfate-S values in all plant parts were very low, less than 500 ppm, dry basis. Most of the sulfate-S absorbed was converted to organic-S. Organic-S and total-S determinations are not recommended for diagnostic purposes.Sulfate-S in blade 1 should be used to diagnose the S status of Italian ryegrass. The critical level of S for growth of the ryegrass is about 100 ppm sulfate-S in blade 1 tissue, dry basis. Concentrations below this value indicate S-deficiency for plant growth.

Nitrogen nutrition of white rose potato in relation to vegetative growth and mineral content of leaves and roots

Abstract White Rose potato plants were transplanted to nutrient solutions provided vith nine treatments of Ca(NO3)2 ranging from 0 to 64 mmoles per liter. Eighteen days later, symptoms of N‐deficiency ranging from very severe to none vere observed. The plants at this time were harvested, and leaves were sampled, oven dried, ground, and then analysed for K, Na, Ca, Mg, NO3‐N, and acetic acid soluble H2PO2‐P. Shoot and fibrous root growth increased with nitrate supply to an optimum, and then decreased with increased nitrate supply, suggesting nitrate toxicity due to the high nitrate supply of the nutrient solution. The nitrate content of the tissues increased with increased nitrate supply. Toxicity due to excess nitrate was associated with a very high nitrate content of the leaf tissues. The critical NO3‐N concentration at a 10% reduction in vegetative growth due to N‐deficiency is about 2000 ppm (0.2%) on a dry basis for the petioles and about 300 ppm (0.03%) for the blades of recently matured leaves.

Rapid preparation of plant samples for cation analysis

Abstract In the dry ashing of plant material for chemical analysis, the hot digestion on the steam bath of the ashed sample was replaced by the quantitative addition of dilute HCl and stirring very briefly to dissolve the ash. By waiting a few minutes for the particles to settle, there was no need to filter the solution prior to dilution with an automatic diluter and the determination of K, Na, Ca and Mg by atomic absorption spectrophotometry. The new procedure permits the handling of large batches of samples conveniently, eliminates the use of pipettes and volumetric flasks and decreases the risk of inadvertent contamination by sodium and therefore enhances accuracy. Precision was at least as good as with the standard procedure and the method is expected to be more suitable for use in conjunction with automated analytical techniques.

Calcium nutrition of the sugarbeet

Abstract When sugarbeet seedlings are transferred from a complete nutrient solution to one from which Ca has been withheld, the rootlets and tops fail to develop. The same transfer at the eight‐leaf stage causes the rootlets to become stubby and swollen at the tips and blade expansion becomes modified; particularly the upper portions of the blades attaining nearly full development, which pucker and often develop a cupping or hooding effect; a unique symptom characteristic of Ca deficiency. As each new leaf develops, the blade area becomes smaller until only a black tip remains at the apex of the petiole, which is the symptom referred to as tip‐burn for this petiole and the successively . shorter petioles formed as Ca deficiency increases in severity. Strangely, these symptoms also appear during periods of rapid growth when the nutrient solution contains as much as 10 to 28 milliequivalents per liter of Ca or when soils are high in Ca. This implies that Ca absorption and possibly translocation limits the C...

Calcium nutrition of white rose potato in relation to growth and leaf minerals.

Abstract White Rose potato plants were grown in nutrient solutions containing Ca from 0 to 20 meq/l. After 32 days of growth, 16 plant parts were taken for analysis. The critical level for the immature to the recently matured leaf was determined to be about 0.15% Ca for the petiole and the blade tissues at the breaking point of the transition zone. Ca concentrations of petioles and blades (dry basis) increased with leaf age with the greatest increase in the blade tissues. The petioles of recently matured leaves under severe Ca deficiency were higher in Na, Mg, and PO4‐P, lower in N03‐N and about the same in K concentration in comparison with non‐deficient petioles while the corresponding blades did not differ appreciably. Calcium deficiency has no major effect on the uptake of these minerals since all values were in the adequate range.

Influence of nitrate and ammonium on critical nitrogen deficiency concentrations and mineral composition of Dupontia fisheri grown hydroponically in a controlled environment

Abstract Dupontia fisheri plants, derived from a clone, were propagated in plant growth chambers by the open‐pot nutrient solution technique, with vermiculite as the solid phase. The plants were illuminated continuously at 21, 500 lux (2,000 f.c.) by a combination of fluorescent and incandescent lamps. Air temperature was kept constant at 20°C. The plants, after transplanting to 20‐liter pots (closed‐pot system), were nourished by a modified half‐strength Hoagland solution, supplied with a one time addition of nitrogen at the rate of zero, 0.25, 0.5, 1.0, 2.0, 4.0 and 8.0 me/1 derived from (NH4)2SO4, Ca(NO3)2 or NH4NO3. They were harvested 49 days after transplanting at a time when those in the three lowest treatments were distinctly deficient in nitrogen. Critical nitrate‐N values (the concentration at a 10% reduction in vegetative growth) were found to be identical, at 100 μg/g (dry basis), in the stem, blade‐1 and blade‐3 tissues, and those for total‐N at 0.901, 2.251, and 2.501, respectively. Absence ...