Showing papers on "Shoot published in 1978"

Patterns of tillering and grain production of winter wheat at a wide range of plant densities.

Abstract: The effect of plant density on the growth and productivity of the various ear-bearing stems of winter wheat was studied in detail to obtain information on the pattern of grain production of crops grown under field conditions. Strong compensation effects were measured: a 160-fold increase in plant density (5-800 plants/m2) finally resulted in a 3-fold increase in grain yield (282 to 850 g DM/m2). Max. grain yield was achieved at 100 plants/m2, which corresponded to 430 ears/m2 and to about 19 000 grains/m2. At higher plant densities more ears and more grains were produced, but grain yield remained constant. Tillering/plant was largely favoured by low plant densities because these allowed tiller formation to continue for a longer period and a greater proportion of tillers produced ears. However, at higher plant densities more tillers/unit area were formed and, despite a higher mortality, more ears were produced. The productivity of individual ears, from main stems as well as from tillers, decreased with increasing plant density and with later emergence of shoots. In the range from 5 to 800 plants/m2 grain yield/ear decreased from 2.40 to 1.14 g DM. At 800 plants/m2 nearly all ears originated from main stems, but with decreasing plant density tillers contributed increasingly to the number of ears. At 5 plants/m2, there were 23 ears/plant and grain yield/ear ranged from 4.20 (main stem) to 1.86 g DM (late-formed stems). Grain number/ear was reduced at higher densities and on younger stems, because there were fewer fertile spikelets and fewer grains in these spikelets. At the low density of 5 plants/m2, plants developed solitarily and grain yield/ear was determined by the number of grains/ear as well as by grain wt. Above 400 ears/m2, in this experiment reached at 100 plants/m2 and more, grain yield/ear depended solely on grain number, because the wt. of grains of the various stems were similar. The harvest index showed a max. of about 44% at a moderate plant density; at this density nearly max. grain yield was achieved. At low plant densities the harvest index decreased from 45% in main stems to about 36% in late-formed stems. However, no differences in harvest index existed between the various ear-bearing stems if the number of ears exceeded 400/m2. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Nitrogenase Activity Measurements in Intact Plants of Alnus incana

Abstract: A technique for C2H2-reduction assay on intact plants of Alnus incana (L.) Moench was evaluated. Cloned plants were grown, in pots, on fine gravel. During assay only the pot was inserted into a Perspex incubation chamber of simple construction. The incubation volume was rather small, plants with various shoot heights could be used, and the shoot was not exposed to the C2H4 produced. Intact plants showed high and constant C2H2-reduction rates during several hours of incubation. In comparison, excised nodulated roots conventionally incubated in test tubes showed low and decreasing rates, due to removal of the photo-synthesizing shoot and injury to the root nodules when drawn from the pot. Repeated nitrogenase activity assays on the same intact individual plants did not affect growth. The technique thus proved useful in studies. where repeated nitrogenase activity measurements are important.

Effects of Nutrients and Light on Growth and Root Formation in Pisum sativum Cuttings

Abstract: Cuttings obtained from seedlings of Pisum sativum L. were rooted in water solution. Shoot growth continued after excision and shoot length increased considerably before roots emerged. Increase in dry weight was strongly dependent on light supply. Continued growth was dependent on supply of mineral nutrients to the rooting solution. Mineral nutrients had no or slight influence on the number of roots formed on cuttings from stock plants grown in fertilized soil, but the growth in length of the roots was dependent on the presence of calcium in the solution. Root formation was dependent on photosynthetic products formed after excision. No roots were formed on cuttings kept in the dark. The number of roots increased with increasing irradiance given to the leafy part of the cutting. At a low level of irradiance sucrose supply through the rooting medium increased the number of roots. Light given to the basal part of the cuttings had a strongly inhibitory effect on the number of roots formed. It is concluded that the carbohydrate level easily becomes a limiting factor for root formation in growing pea cuttings. Availability of mineral nutrients influences in the first place the growth of the shoots.

Effect of Waterlogged Soil Conditions on the Production of Ethylene and on Water Relationships in Tomato Plants

Abstract: The roots of tomato plants (Lycopersicon esculentum Mill., cv. Moneymaker) were exposed to low concentrations of oxygen by waterlogging the soil or by growing the plants in nutrient solution flushed with nitrogen gas. After 24 h, the rate of ethylene production by the petioles, main stem, and shoot apex was increased by 4-6-fold and the petioles developed epinastic curvatures. Removing the roots did not reproduce these responses. The amounts of ethylene produced by shoot tissues in response to physical wounding was greatly increased by waterlogging the soil. The production of ethylene by roots was suppressed by the absence of oxygen. When the roots were transferred back to an aerobic environment ethylene production quickly exceeded that observed in roots maintained continuously in aerobic conditions. The enhanced rate of ethylene production in the shoots occurred in the absence of increased water stress as measured with a leaf pressure chamber; leaf water potentials were increased rather than decreased by waterlogging for 30 h or more. This was associated with stomatal closure and reduced transpiration. Resistance to water flow through the plant increased as transpiration decreased in response to waterlogging. However, at similar rates of transpiration, resistance was normally lower in waterlogged plants than in controls.

Shoot, Stolon, and Tuber Formation on Potato (Solanum tuberosum L.) Cuttings in Response to Photoperiod

Abstract: The intensity of “tuberization stimulus” in potato shoots (Solanum tuberosum L.) can be assessed from cuttings containing one or more leaves. Cuttings maintained in a mist chamber under long days will form tubers from underground buds if prior to taking the cutting the leaves received sufficient exposure to photoperiods less than the critical photoperiod. The greatest tendency to tuberize was found in cuttings that consisted of a single, fully expanded leaf and its subtended bud. Grafts showed that genetical differences in critical photoperiod resided in properties of the leaf. Short days before cutting tended to shift growth from above ground buds of two-node cuttings to below ground buds, even if the number of short days was insufficient for tuber induction. As few as 6 short days reduced growth of shoots at the upper bud and increased underground growth of shoots and stolons.

Nickel in Plants: II. Distribution and Chemical Form in Soybean Plants.

Abstract: The gross tissue distribution, intracellular fate, and chemical behavior of Ni 2+ in soybean plants ( Glycine max cv. Williams) were investigated. Following root absorption, Ni was highly mobile in the plant, with leaves being the major sink in the shoots for Ni during vegetative growth. A senescence >70% of the Ni present in the shoot was remobilized to seeds. Fractionation of root and leaf tissues showed >90% of the Ni to be associated with the soluble fraction of tissues; ultrafiltration of the solubles showed >77% of the Ni to be associated with the 10,000 to 500 molecular weight components of both roots and leaves. Chemical characterization of the soluble components (10,000 to 500 and >500 molecular weight) by thin layer chromatography and electrophoresis resolved a number of Ni-containing organic complexes. Major Ni-containing components formed in the root are transported in the xylem stream, and undergo partial modification on deposition in leaves. Nickel accumulated in seeds is primarily associated with the cotyledons. Chemical fractionation of cotyledon components showed 80% of the Ni to be associated with the soluble whey fraction, while 70% of this fraction was composed of Ni-containing components with molecular weight

Effects of Root Anaerobiosis on Ethylene Production, Epinasty, and Growth of Tomato Plants

Abstract: Experiments were performed to determine the source(s) of ethylene-causing epinasty in flooded tomato plants (Lycopersicon esculentum Mill.). Simultaneous measurements were made of ethylene synthesized by the roots and shoots of tomato plants exposed to either aerobic or anaerobic atmospheres in the root zone. When the root zone was made anaerobic by a flowing stream of N2 gas, petiole epinasty and accelerated ethylene synthesis by the shoots were observed. In soil-grown plants, ethylene synthesis by the root-soil complex increased under anaerobic conditions; but when grown in inert media under the same conditions, ethylene synthesis by roots remained constant or declined during the period of rapid epinastic growth by the petioles. Other characteristic symptoms of flooding, e.g. reduced growth and chlorosis, were also observed in plants with anaerobic roots. Pretreatment of plants with AgNO3, an inhibitor of ethylene action, completely prevented epinasty, demonstrating that ethylene is the agent responsible for waterlogging symptoms. These results indicate that deprivation of O2 to the roots is the primary effect of soil flooding, and that this is sufficient to cause increased ethylene synthesis in the shoot. The basis of the observed root-shoot communication is unknown, but root-synthesized hormones or specific ethylene-promoting factors may be involved.

Synergistic inhibitory effects of vanillic and p-hydroxybenzoic acids on radish and grain sorghum

Abstract: Radish and grain sorghum germination and sorghum growth were inhibited in a synergistic manner by combinations of vanillic andp-hydroxybenzoic acids. At threshold inhibition levels, 2.5 × 10−3 M vanillic acid-treated radish seeds had 71 % of control germination after 24 hr and 2.5 × 10−3 Mp-hydroxybenzoic acid-treated radish yielded 95% germination. A mixture of 2.5 × 10−3 M of each of these two phytotoxins showed 52% germination after 24 hr. Equimolar mixtures of 5 × 10−3 M vanillic andp-hydroxybenzoic acids allowed sorghum germination of 60% of untreated seeds after 24 hr, whereas separate treatments of individual phenols had 93% and 96% of control seed germination. Sorghum root and shoot elongation and total seedling growth were more sensitive than germination to vanillic andp-hydroxybenzoic acid treatments, and synergistic effects also were apparent. A combination of 5 × 10−3 M vanillic with 5 × 10−3 Mp-hydroxybenzoic reduced root length more than either did individually, and a mixture of 5 × 10−4 M vanillic with 5 × 10−4 Mp-hydroxybenzoic acid reduced sorghum seedling growth to approximately that resulting from a 10−3 M concentration of either phenol alone. Phytotoxin levels inhibitory to sorghum growth caused small increases in lower leaf surface diffusive resistance, but did not close stomates, and this effect was not judged to be the cause of reduced sorghum growth.

Contribution of overwintering leaves to the growth of three broad-leaved, evergreen shrubs belonging to the Ericaceae family

Abstract: Individual leaves of three bog ericads, leatherleaf (Chamaedaphne calyculata), bog laurel (Kalmia polifolia), and Labrador tea (Ledum groenlandicum), were retained for a maximum of two growing seasons in a peat bog in southern Ontario. The premature loss of mature leaves, resulting from artificial defoliation, significantly reduced the growth of new shoots of L. groenlandicum and K. polifolia but not of C. calyculata. Defoliation effects were directly proportional to the normal retention time for overwintering leaves. Mature leaves probably translocate photosynthate, nitrogen, and phosphorus to other plant parts. This would explain why leaf dry weights were greatest at the start, rather than at the end, of the leaves' second growing season. Net photosynthetic rates decreased with leafage, but in terms of leaf nitrogen content, new and old leaves fixed equal amounts of carbon.

Interdependence of Root and Shoot Activities in Determining Nitrogen Uptake Rate of Roots

Abstract: Tobacco plants (Nicotiana tabacum L.) were grown under PAR with accumulated daily totals of 10.5, 18.0, 25.5, 33.0, and 40.5 Einsteins m-2day-1 and day/night temperatures of 26/22 and 22/18 C. Plants were sampled at 2-day intervals during exponential growth. Total dry matter and nitrogen in the whole plant and dry matter in the roots increased with PAR and temperature; however, their proportionalities were not constant. The RGRR and RARNP were nearly equal to each other at each PAR and temperature, and both were approximately equal to the RARSR. Depending on treatment conditions, soluble carbohydrates in roots remained constant during exponential growth at 5%-9%. These results support a model for dependence of the nitrogen-supplying function of roots on the concurrent transport of soluble carbohydrate from the shoot.

Partitioning of Sugar between Growth and Nitrate Reduction in Cotton Roots.

Abstract: The level of endogenous sugars was inversely related to nitrate availability in young cotton ( Gossypium hirsutum L.) plants, with high nitrate causing a greater decline in sugar content of roots than of shoots. High nitrate (low sugar) plants also displayed relatively more shoot growth and less root growth than low nitrate (high sugar) plants. These data are consistent with the theory that roots are poor competitors for sugar, and that sugar supply is a major factor limiting root growth in vivo. The effects of endogenous sugar level on root growth and on nitrate reductase activity in the root were different. When root sugar level was experimentally controlled by varying nitrate concentration in the nutrient solution, root growth was less sensitive than nitrate reductase activity to sugar deficiency. Also, in sterile root tips cultured on media containing a wide range of sucrose concentrations, growth rate was considerably less sensitive to endogenous sugar deficiency than was nitrate assimilation rate. Similarly, in plants which were detopped or girdled, nitrate reductase activity in the roots declined more rapidly than did root sugars, especially glucose and fructose. These results suggest that when sugar is deficient, cotton roots preferentially use it for growth at the expense of nitrate reduction.

Cadmium Uptake and Distribution in Tolerant and Non-Tolerant Populations of Holcus lanatus Grown in Solution Culture

Abstract: Cadmium uptake and distribution between roots and shoots of a tolerant and a non-tolerant population of Holcus lanatus were studied with reference to both concentration and total cadmium content. The uptake of cadmium into roots of both normal and tolerant plants from nutrient solutions containing 1 ppm cadmium is extensive and in normal plants as much as 90% of the whole plant cadmium remains in the roots but translocation allows shoot concentrations to reach 145 ppm. In tolerant plants translocation of cadmium to shoots is further reduced with a concomitant increase of cadmium concentration in the roots. These effects are shown to be due to differences in biomass and metal uptake of the two populations.

Control of Adventitious Root Production and Hypocotyl Hypertrophy of Sunflower (Helianthus annuus) in Response to Flooding

Abstract: The morphological changes of the shoots of Helianthus annuus cv. Russian caused by varying periods of flooding of the roots were studied. Attention was focused on adventitious root formation and hypocotyl hypertrophy which are known to be caused by excess water around the roots in the absence of anoxia. Twenty-four hours of flooding was found to be sufficient to cause both of these responses. Experiments involving flooding, leaf removal, shoot apical bud removal, two different light intensities, and a treatment in which only a small proportion of the roots were flooded suggested that a major factor causing the flood-induced changes in the hypocotyl arises in the root but other factors may come from the leaves. In the longer-term experiments other flood-induced changes in shoot morphology were leaf epinasty, death of shoot apex, extreme chlorosis and hypertrophy of nodes and internodes. There was no apparent contribution of adventitious roots to the survival of flooded plants.

Growth and Nutrient Uptake of Soybean Roots Under Field Conditions1

Abstract: Although soybean (Glycine max L. Merr.) root growth in soil has been measured, the nutrient flux characteristics of the roots during the growth of the plant in the field have not. Soybean root amount and distribution were measured using approximately biweekly samplings during the growth of ‘Williams’ soybeans on Chalmers silty clay loam soil (Typic Argiaquoll) near Lafayette, Ind., in 1973, 1974, and 1975. Root length and fresh weight were measured with depth and distance from the row. Shoot samples taken at each sampling were analyzed for P and K. Shoot growth rate averaged 135 kg ha⁻¹ day⁻¹ between plant ages of 50 and 100 days. Shoot concentration of P decreased until 60 days then increased as beans began to form. Shoot concentration of K decreased during the sampling period. Root length increased until 70 to 80 days, remained constant to 100 days, and then decreased. Maximum root length averaged 24 cm per cm² of soil surface. Average proportion of the roots in the 0 to 15 cm layer increased with plant age after 36 to 49 days and reached a maximum of 59% at 113 to 120 days. Soybean root density was approximately one-fifth that observed at the same location for corn (Zea mays L.). Influx of P and K into soybean roots was less than with corn during early growth but more than corn later in the season. This result indicates that soybeans may not respond to fertilizer banded near the seed at planting but would require higher P and K fertility in the whole rooting volume of soil than corn after 50 days in order to sustain the required nutrient influx into the roots.

Organogenesis and Plantlet Formation from Organ- and Seedling-Derived Calli of Rice (Oryza sativa)

Abstract: Callus was induced in different somatic organs of Oryza sativa L. Specific minimum 2,4-dichlorophenoxyacetic acid (2,4-D) concentrations in the medium were necessary for the induction of callus from different organs while high levels of 2,4-D (6–10 mg/l) induced callus formation in each organ tested. The optimum 2,4-D concentration for callus induction and growth for root-derived calli was 2 mg/l and for leaf-derived 6 mg/l. Root and shoot organogenesis were induced in both root- and leaf-derived calli by sub-culturing to a medium lacking 2,4-D. Root organogenesis occurred at a higher frequency than shoot organogenesis. Shoot organogenesis rarely occurred in calli without differentiated roots. Increased age of callus cultures almost completely inhibited shoot development. The addition of the cytokinin 6-γ,γ-dimethylallyl-amino purine partially restored the potential for shoot organogenesis. Whole plants were easily recovered from the calli and grown to maturity with some plants exhibiting phenotypic abnormalities.

Induction of Adventitious Buds on Embryos of Norway Spruce Grown in vitro

Abstract: Adventitious buds were induced when isolated embryos of Norway spruce (Picea abies L.) were cultured on a defined medium containing 2iP. Anatomically different bud primordia were formed at high and low cytoldnin concentrations. The highest percentage of embryos forming bud primordia was obtained after 4–5 weeks on 2iP medium. Buds developed after transfer of the induced embryos to medium without growth regulators. Many of the buds developed into elongated shoots. No root primordia were observed in any of the induced embryos.

Effect of growth regulators and role of roots in sex expression in spinach.

Abstract: When 7-d-old plantlets of spinach (Spinacia oleracea L.) were immersed with their roots for 24 h in 25 mg/l gibberellic acid (GA3), or 15 mg/l 6-benzylaminopurine (6-BAP), or 15 mg/l indole-3-acetic acid (IAA), or 10 mg/l abscisic acid (ABA) and subsequently grown on long (18-h) days, the ratio of plants with male and female flowers, which in the controls was almost 1:1 (48 and 52%, respectively), was greatly altered. The treatments with 6-BAP, IAA and ABA raised the percentage of female plants to 88, 76 and 71%, respectively; the GA3 treatment increased the percent of male plants to 79%. When young, vegetative spinach plants (3 visible leaves) grown in 18-h days were cut a the root neck, and the shoots grown with their bases in nutrient solution, with adventitious roots either being allowed to develop or being systematically removed, 85% of the plants without roots became males, 85% of those with roots became females. But if the cut shoots were first, for 28 h, placed in a 15-mg/l 6-BAP solution and then grown in the absence of roots, the percent of female plants was restored to 84. These results fully agree with those obtained previously with hemp, namely, that plant growth regulators exert a regulating effect on the sex expression of dioecious plants when applied through the roots in early stages of development; that the root system plays an important role in determining the sex of these plants, that this role of the roots is associated with the synthesis of cytokinins in them. Dioecious short- and long-day plants do not differ in these respects.

The Effect of Competition and Salinity on the Growth of a Salt Marsh Plant Species

Abstract: Young rhizome sprouts of the herbaceous perennial Jaumea carnosa were propagated from material collected in a salt marsh along the central California coast The sprouts were transplanted to flats of sand sown with different densities of seeds of a representative glycophyte, Lolium perenne L "Derby, turf type" Controls flats contained only Jaumea or Lolium Three series of replicated flats were watered from above with dilutions of seawater in 1/10 strength Hoagland solution, such that dissolved salts were 400, 4000 or 11,600 ppm Two other series were continuously subirrigated with 400 or 11,600 ppm salt water After 61 days of treatment in a greenhouse with a 30/11°C thermoperiod (mean daily max/min), all plants were harvested and weighed In the monospecific control flats, the growth of both species declined with increasing salinity, but the relative decline of Lolium was three times that of Jaumea Jaumea's root: shoot ratio was also less affected by salinity Both species grew well when subirrigated by 400 ppm salt water, but grew poorly when subirrigated by 11,600 ppm salt water, indicating that aeration alone is not the most significant factor in the marsh The effect of interspecific competition on Jaumea was marked at low salinity, depressing growth by 52% compared to controls, but at high salinity the competitive effect was insignificant, whether the plants were watered from above or subirrigated This supports the hypothesis that intolerant halophytes such as Jaumea are restricted in nature to salt marshes because they are poor competitors with glycophytes on non-saline soils

A Comparative Anatomical Study of Organogenesis in Cultured Tissues of Maize, Wheat and Oats

Abstract: Five cereals and two related grasses were tested for adventitious shoot production from tissue cultures using methods concordant with those reported to be successful for cereals. The five cereals I wheat (Triticum aestivum L.), oats (Avena sativa L.), and maize (Zea mays L.) Pioneer hybrid 3369A, the Bolivian race Pororo and the Equadorian race Chococenol were all found to proliferate in culture through an aberrant root-like mechanism of growth which had the external appearance of callus. Two related species, teosinte (Zea mexicana Reeves and Mangelsdorf) and tripsacum (Tripsacum dactyloides L.), were less successful in culture, but grew in the same way. Oats, and probably Pororo and Chococeno, initiated presumptive shoot meristems directly from root vascular tissues within this root-like growth. Hybrid maize and wheat initiated no shoot meristems and produced only roots. The occasional shoot production observed in wheat was discounted as simple carryover of existing shoot apices from the primary embryo cultures. This study suggests that the incidence of shoot regeneration in cultures of these cereals may be related more directly to adventitious bud formation on roots than to any controlled de novo organogenesis from undifferentiated callus.

Effects of season and level of grazing on the utilization of heather by sheep 1. Responses of the sward

Abstract: The effects of sheep grazing on the development and production of heather swards were studied over a period of 3 years in an experiment in which sheep numbers were adjusted to remove 0, 40% or 80% by weight of the current season's shoots in summer and in autumn. The number of shoots grazed increased with the level of grazing but not in direct proportion. The length of shoot grazed was greater at the 80% level of grazing. Heavy autumn grazing was associated with frequent uprooting and breaking off of shoots and with a high incidence of shoots grazed down to the previous season's wood. The siting of new season's shoots was influenced by the amount of shoot length grazed in the previous season. Grazing behaviour of sheep within a plot was affected by variation in heather cover with the sheep showing a tendency to graze near bare areas. After 3 years of grazing, standing crop was reduced by both levels of grazing whether in summer or autumn. New shoot production was unaffected on plots which had had the 40% level of shoot removal but was reduced by half on plots which had had the 80% level of shoot removal whether in summer or autumn. A clipping experiment was also carried out where 0, 40% or 80% of the length of current shoots was removed in May, early July and Septeinber. Standing crop was unaffected by May clipping but was reduced on plants with a history of 80% shoot removal in July or September. New shoot production was only reduced on clipped plants which had been subjected to 80% removal in September. The role of overwintering green shoots and carbohydrate reserves in the support of new shoot growth was considered. The implications of the results in relation to heather management are discussed.

Photoperiod-induced changes in gibberellin metabolism in relation to apical growth and senescence in genetic lines of peas (Pisum sativum L.).

Abstract: In an early-flowering line of pea (G2) apical senescence occurs only in long days (LD), while growth in short days (SD) is indeterminate. In SD, G2 plants are known to produce a graft-transmissible substance which delays apical senescence in related lines that are photoperiod-insensitive with regard to apical senescence. Gibberellic acid (GA3) applied to the apical bud of G2 plants in LD delayed apical senescence indefinitely, while N6-benzyladenine and α-naphthaleneacetic acid were ineffective. Of the gibberellins native to pea, GA9 had no effect whereas GA20 had a moderate senescence-delaying effect. [3H]GA9 metabolism in intact leaves of G2 plants was inhibited by LD and was restored by placing the plants back in SD. Leaves of photoperiod-insensitive lines (I-types) metabolized GA9 readily regardless of photoperiod, but the metabolites differed qualitatively from those in G2 leaves. A polar GA9 metabolite, GAE, was found only in G2 plants in SD. The level of GA-like substances in methanol extracts from G2 plants dropped about 10-fold after the plants were moved from SD to LD; it was restored by transferring the plants back to SD. A polar zone of these GA-like materials co-chromatographed with GAE. It is suggested that a polar gibberellin is synthesized by G2 plants in SD; this gibberellin promotes shoot growth and meristematic activity in the shoot apex, preventing senescence.

Effect of replacing nutrient potassium by sodium on uptake and distribution of sodium in tomato plants

Abstract: Tomato plants (Lycopersicon esculentum cv. Amberley Cross) were grown in a series of nutrient solutions in which 0, 60, 90, 95, 98 and 99 per cent of the K was replaced by Na. The plants selectively absorbed K relative to Na from the nutrient solutions and transported K to the shoots in preference to Na. In the nutrient solution having the highest K/Na ration most of the Na taken up by the plants accumulated in the roots, but as the K was progressively replaced by Na an increasing proportion of the total Na absorbed was transported to the leaves. Sodium was present at up to 2.4 per cent of the dry wt of whole, fully-expanded leaves without there being any apparent visual signs of damage or reduction in the rate of growth of the plants. On closer examination it was found that most of the Na transported to the leaves was excluded from the laminar tissue and accumulated in the adjacent petioles. The ability of the roots and petioles to retain large amounts of Na depended on an adequate supply of K to the plants.