The influence of the transpiration rate on uptake and transport of potassium ions in barley plants

Hooymans, J. J. M.

doi:10.1007/bf00387465

Cited by 24 publications

(11 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2). This phenomenon has been noted by others (7,10,12), but it is not clear why it occurs. Equally unclear is the reason NRA decreased only slightly under these conditions (Fig.…”

Section: Discussionmentioning

confidence: 80%

Nitrate Reductase Activity in Maize (Zea mays L.) Leaves

Shaner¹,

Boyer²

1976

Plant Physiol.

143

View full text Add to dashboard Cite

Experiments were conducted to determine whether the nitrate flux to the leaves or the nitrate content of the leaves regulated the nitrate reductase activity (NRA) Nitrate reductase activity is sensitive to changes in the water status of plants and is inhibited when the water potential of plants declines (1,9,14). Morilla et al. (14) (4), in the same tissue used for determination of NRA and nitrate content.Extraction and Assay of NRA and Leaf Nitrate Content. Samples (1 g) of leaf tissue taken from all the leaves of several plants were ground for 35 sec with a Polytron (Brinkman Instruments, N. Y.) in 6 ml of extraction medium (18). The homogenate was centrifuged at 27,000g for 15 min, and the supernatant was used to assay both NRA (17) and leaf nitrate content (13). NRA was expressed on the basis of dry weight. The assays were conducted between the 3rd and 9th hr of the photoperiod when the NRA remained constant within 10%, and endogenous factors regulating the activity of the enzyme were not operating or were constant. All experiments were repeated at least twice.Collection RESULTSWhen 8-day-old maize seedlings were desiccated, there was a steady decrease in NRA as I' decreased (Fig. 1, A and E). Upon rewatering the tissue with a nitrate-free medium, NRA recovered to 80% of the control level, and T'Is also recovered (Fig. 1, A and E

show abstract

“…2). This phenomenon has been noted by others (7,10,12), but it is not clear why it occurs. Equally unclear is the reason NRA decreased only slightly under these conditions (Fig.…”

Section: Discussionmentioning

confidence: 80%

Nitrate Reductase Activity in Maize (Zea mays L.) Leaves

Shaner¹,

Boyer²

1976

Plant Physiol.

143

View full text Add to dashboard Cite

show abstract

“…For example, Brag (1972) found a negative relationship between transpiration rate and concentration of K in wheat ( Triticum aestivum L.) and in pea ( Pisum sativum L.) grown in nutrient solution, while transpiration was closely related to the influx of Rb (tracer for K) (Jensen and Petterson 1980). On the other hand, entry of K into the roots of intact barley plants was independent of transpiration rate (Hooymans 1969). These results on other crops and the results in the current study suggest that water use or transpiration rate does not account for the accumulation of K (in the whole grapevine or whole shoot, unit laminae or unit shoot) in rootstocks grown on own‐roots.…”

Section: Discussionmentioning

confidence: 99%

Accumulation of potassium in grapevine rootstocks (Vitis) as affected by dry matter partitioning, root traits and transpiration

Kodur

Tisdall

Tang

et al. 2009

Australian Journal of Grape and Wine Research

View full text Add to dashboard Cite

Background and Aims: A high concentration of potassium (K) in grape juice can lead to high juice pH (e.g. >3.8) and, in turn, wine of lower quality. The concentration of K in grapevine can be controlled by rootstocks. However, the differences between rootstocks in the accumulation of K in grapevines and mechanisms of regulation of K are not well known. The current study addresses these issues. Methods and Results: Rootstocks (on own‐roots) Freedom, Schwarzmann, 1103 Paulsen, 110 Richter, 140 Ruggeri and 101‐14 Millardet et de Grasset were grown in sand for 56 days in a glasshouse and watered daily with 3 mM K. At Day 56, rootstock 1103 Paulsen had the highest total K uptake, while 101‐14 Millardet et de Grasset and 140 Ruggeri had the highest concentration of K in shoot and roots, respectively. Total K uptake in rootstocks was positively related to the dry weight of the whole grapevine, relative growth rate, total root length and total root surface area. Translocation efficiency of K in rootstocks was positively related to shoot : roots dry weight and shoot demand for K per unit root weight. Total K uptake and accumulation of K into the shoot were not affected by transpiration, but concentration of K in the shoot was positively related to the concentration of K in the xylem sap. Conclusions: The results show genetic differences between grapevine rootstocks in K uptake and transport, and highlight the importance of growth, dry matter partitioning, root traits and root pressure, and the lack of significance of transpiration, in the accumulation of K.

show abstract

“…It is possible that removal of these ions from the xylem by a constant flushing of the vessels prevents theeir backward leakage into the cells of the stelar parenchyma (6). Alternatively, enhanced removal of ions upward in the xylem with the increased water flux could maintain a more efficient active translocation mechanism which otherwise might be inhibited by high ion concentrations (14). If either of these postulates is valid, it follows that the nitratestimulated water flux (the mechanism of which is unknown at present) would serve to enhance the translocation of most transportable ions and organic substances.…”

Section: Discussionmentioning

confidence: 99%

Nitrate Translocation by Detopped Corn Seedlings

Ezeta¹,

Jackson²

1975

Plant Physiol.

View full text Add to dashboard Cite

Five-day-old seedlings of corn (Zea mays L.) grown without nitrate were decapitated and exposed to 0.5 mM KNOs or 0.5 mM KCI in aerated solutions at 30 C. Uptake of nitrate, chloride, and potassium was determined by replacing solutions hourly and measuring their depletion. Translocation of these ions and of organic nitrogen was determined by hourly analysis of the vascular exudate. Nitrate reduetion was estimated by the difference between nitrate uptake and nitrate recovered in the tissue and exudate. Nitrate uptake exhibited its usual pattern of apparent induction resulting in the development of an accelerated uptake phase. Chloride uptake remained fairly constant throughout the experimental period. Translocation of nitrate increased progressively for at least 7 hours whereas chloride translocation reached a maximum about the 3d hour and then declined to a lower rate than nitrate translocation. Nitrate uptake and translocation were restricted by anaerobiosis, by 20 and 40 C relative to 30 C, and by 0.05 mM 6-methylpurine, an RNA-synthesis inhibitor. Accumulation, reduction and translocation of nitrate had different sensitivities to all these factors. (17,18). Data are presented to support the concept that continuous nitrate uptake is required to maintain significant translocation of nitrate. In addition, the translocation of organic nitrogen was strongly dependent upon continuous nitrate uptake. MATERIALS AND METHODSThe procedures were, in general, similar to those described by Jackson et al. (17). All experiments were conducted with corn (Zea mays L.) hybrid DeKalb XL45. Four days after germination in darkness with 0.1 mm CaSO, the secondary roots were excised and five seedlings were assembled in a Plexiglas holder especially designed to fit the top of a 75-ml Taylor tube. Seedlings were then placed in a pretreatment solution for 24 to 36 hr in darkness prior to initiating the experiment. The pretreatment solutions contained per liter 0.25 mM (NH)2SO,, 0.6 mmY K2SO4, 0.4 mM KH2PO4, 1.6 mM MgSO4, 0.8 mm CaSO4, and 250 mg CaCO,. Iron was supplied as Fe-EDTA at 1.8 mg per liter; the remaining five micronutrients were present at one-fifth the concentration of Hoagland's solution (13).The standard uptake solution contained 0.5 mM KNO or 0.5 mM KCl plus 0.25 mm CaSO4, pH 6. For the experiments involving temperature, 6-methylpurine, or anaerobiosis variables, the uptake solutions also contained 1 mm Na 2-[Nmorpholino]ethanesulfonate as a buffer and the bactericide chloramphenicol at 20 jtg mP. Except where indicated, solutions were continuously aerated and the temperature was maintained at 30 C. Solutions were changed hourly and nitrate, chloride, and potassium uptake determined from depletion of the solutions. Five plants per 70 ml were employed for each replication. Four of these five-seedling units were used as replicates for each treatment and the data presented are the averages of the four replicates.Immediately after placing the plants in the uptake solutions, the mesocotyls were excised below the firs...

show abstract

The influence of the transpiration rate on uptake and transport of potassium ions in barley plants

Cited by 24 publications

References 10 publications

Nitrate Reductase Activity in Maize (Zea mays L.) Leaves

Nitrate Reductase Activity in Maize (Zea mays L.) Leaves

Accumulation of potassium in grapevine rootstocks (Vitis) as affected by dry matter partitioning, root traits and transpiration

Nitrate Translocation by Detopped Corn Seedlings

Contact Info

Product

Resources

About