Polyamine accumulation in foliage was assessed in relation to ammonium accumulation and ethylene evolution in tomato (Lycopersicon esculentum Mill.) under nutritional stress. Nutritional stresses were induced in greenhouse-grown plants in quartz sand with an NH4-based solution or with NO3-based solutions without P, K, Ca, or Mg. Plants receiving NH4-based nutrition had higher putrescine and lower spermidine concentrations than plants receiving NO3-based nutrition. Adding AOA (10-5 m) to the nutrient solution of plants receiving NH4-based nutrition suppressed putrescine accumulation but had no effect on spermidine; silver thiosulfate (10-5 m) had no effect on polyamine accumulation. Deficiencies had no consistent effect on polyamine accumulation relative to its accumulation under full-nutrition conditions, but adding AOA restricted putrescine and spermidine accumulation in all nutrient-deficient regimes. Foliar spermine accumulation was not affected by nutritional regime. Ammonium-based nutrition resulted in enhanced putrescine and ammonium accumulation and accelerated ethylene evolution rates relative to plants receiving NO3-based nutrition. All nutrient-deficient plants had higher ammonium accumulation, and all but P-deficient plants had higher ethylene evolution than those receiving full NO3-based nutrition. Although some variability occurred among treatments, an association among putrescine accumulation, ammonium accumulation, ethylene evolution. and stress-induced symptoms was apparent. Chemical name used: (aminooxy) acetic acid (AOA).
Acidification of the irrigation water with phosphoric acid is a common practice to avoid nutrient deficiencies/toxicities from alkaline root media. It has been suggested high phosphorus levels could cause phosphorus toxicity.
Euphorbia pulcherrima Willd. cultivars Supjibi and Celebrate 2 cuttings were potted on June 6, 1991 in a root medium of peat, perlite and soil (40:40:20 by volume) amended with N, K, Ca and micro-nutrients, plus six phosphorus (0-40-0) rates of .89, 1.78, 3.55, 7.11, 10.67, and 14.22 kg/meter3. Foliar samples were analyzed for NH4, P, and K every two weeks after the start of short days. Root media samples were also collected and analyzed pH, SS and NO3, P, K and NH4. Bract diameter, bract edge burn, days to anthesis, and plant height were recorded at anthesis.
Media P levels increased as the phosphorus rate increased, but a significant treatment*harvest interaction for media P was observed. There was decreased bract size and increased incidences of bract edge burn as phosphorus rate increased. Root media P levels did not affect the levels of other nutrient elements in the foliar samples. No visual symptoms of phosphorus toxicity was observed except for bract edge burn at anthesis.
Abstract
Seedlings of ‘Lovell’ and ‘Elberta’ peach [Prunus persica (L.) Batsch] were grown in the greenhouse for 29 or 50 days in nutrient solutions containing 8, 16, 33, 66, 132, 264, or 660 µM Ca at pH 4.5. Relative growth rate was unaffected by Ca concentrations. Calcium concentration in the stems was increased from 700 to 4330 µg/g dry weight and in the roots from 348 to 1787 µg/g dry weight by Ca treatments for the 29 days of growth. No Ca deficiency symptoms were observed on the seedlings when the Ca concentration in the leaves exceeded 2300 µg/g dry weight. The Ca uptake rates during the 29 days of growth for ‘Lovell’ increased from 0.46 to 3.77 and for ‘Elberta’ from 0.44 to 2.84 µmoles/g fresh-weight-root/day. After 50 days of growth, Ca uptake rates increased for ‘Lovell’ from 0.58 to 3.51 and for ‘Elberta’ from 0.52 to 3.02 µmoles/g fresh-weight-root/day. Calcium accumulated in stems when Ca concentration in the nutrient solution exceeded 264 µm Ca with no change in total Ca content in the roots. The K and P uptake rates were increased by higher Ca treatments but the Mn uptake rate was decreased when the Ca concentration in nutrient solution was greater than 66 µm.
Root ferric chelate reductase (FCR) activity in Annona glabra L. (pond apple), native to subtropical wetland habitats and Annona muricata L. (soursop), native to non-wetland tropical habitats, was determined under Fe-sufficient and Fe-deficient conditions. Four-month-old seedlings of each species were grown hydroponically in a complete nutrient solution containing 90 μm Fe or no Fe. The degree of tolerance of Fe deficiency was evaluated by measuring root FCR activity, chlorophyll and Fe concentration in recently matured leaves and plant growth. Root FCR activity was higher in soursop than in pond apple in the nutrient solution with Fe. However, there were no differences in root FCR activity between species under Fe-deficient conditions. Root FCR activity in pond apple and soursop was not induced in the absence of Fe. Leaf chlorophyll index and Fe concentration, and dry weights of pond apple were lower when plants were grown without Fe compared to plants grown with Fe. Leaves of pond apple grown without Fe became chlorotic within 3 weeks. Lack of Fe decreased the chlorophyll index and Fe concentration in young leaves less in soursop than in pond apple. In contrast, the Fe level in the nutrient solution had no effect on dry weights of soursop. The rapid development of leaf chlorosis and low FCR activity of pond apple may be due to its native origin in wetland areas where there is sufficient soluble Fe for plant growth and development.
Several experiments on multispectral radiometer showed its suitability in driving nitrogen fertigation in tomato crop. Nir-Green light ratio describes crop nitrogen status well, highlighting element deficiency or excess, which is a great help to farmers in choosing timing and intensity of fertilizer application. The scientific literature reports several studies about nitrogen management only, but not phosphorus and potassium. Because of the advantage obtained with N, it would be desirable to also adapt it to phosphorus and potassium management. For this purpose, a preliminary trial was carried out on the omato cultivar Brigade grown in pots in a greenhouse. Four nutrient solution were supplied. Three were lacking in N, P, or K—the last had all elements needed for a balanced growth. Radiometer readings were taken once a week during the crop cycle, around noon. First results were encouraging. After some data elaboration, it appeared evident that, in some cases, it was possible to set the fertigation treatments apart by only having a look at the single wavelengths measured by the instrument. Through the Nir/green index, used in N management, phosphorus deficiency was identified as well. Potassium trend line was completely different from those of nitrogen and phosphorus, and very similar to that of the control. The utilization of the radiometer in handling potassium fertigation in tomato appeared somewhat difficult. Its application might be desirable, instead, for phosphorus fertigation in addition to nitrogen. The 560 and 710 nm wavelengths might be the especially more useful for this purpose, although a simple index or a combination of some simple indices able to identify phosphorous deficiency/excess and to screen them from those induced by nitrogen are needed.
AZ ( Table 1 ). For certain nutrients N deficiency prolonged uptake of nutrients other than N after maximum net biomass was attained. For example N-deficient PJM accumulated P, Ca, Cu, and Zn after maximum biomass was attained, whereas maximum biomass
Abstract
Three cultivars of strawberry (Frageria × ananassa Duch. cvs. Redcoat, Midway and K68-108) were grown in sand culture and supplied with 4 levels of Boron interacted with 3 levels of Phosphorous. Leaf B values of 2-5 ppm were associated with B deficiency symptoms in ‘Redcoat’ and K68-108. Maximum vegetative growth was obtained when leaf B ranged from 58-116 ppm for ‘Redcoat’ and K68-108 and from 14-33 ppm for ‘Midway’. Leaf P and B were increased when P and B levels in the nutrient treatments increased, however there were no significant leaf P-B interactions exhibited. Leaf Ca increased and leaf K decreased as each cultivar approached maximum growth. Leaf B values for ‘Redcoat’ and K68-108 that were associated with maximum growth were similar to those associated with maximum growth in rutabagas, sugarbeets, barley and several forages. ‘Midway’ was found to be very sensitive to B additions.
Abstract
Northern red oak (Quercus rubra L.) seedlings were grown in six container configurations differing in diameter, length, and volume. More shoot and lateral root dry weight was produced in a cylindrical polyvinylchloride (PVC) container 15.4 × 36 cm containing 6333 cm3 of potting medium than in containers with less medium volume. Seedling growth did not increase in a 15.4 × 110 cm container even though the potting medium volume was increased. Of all container variables measured, the ratio of potting medium surface area to potting medium depth (SA:D) showed the best correlation to seedling dry weight accumulation. Water or nutrient deficiencies could not be eliminated as factors contributing to differences in seedling growth.
Marigold (Tagetes erecta L.) grown hydroponically in an irradiated nutrient solution containing FeDTPA had root ferric reductase activity 120% greater, foliar Fe level 33% less, and foliar Mn level 90% greater than did plants grown in an identical, nonirradiated solution, indicating that the plants growing in the irradiated solution were responding to Fe-deficiency stress with physiological reactions associated with Fe efficiency. The youngest leaves of plants grown in the irradiated solution had symptoms of Mn toxicity (interveinal chlorosis, shiny-bronze necrotic spots, and leaf deformation). Plants grown in irradiated solution in which the precipitated Fe was replaced with fresh Fechelate were, in general, no different from those grown in the nonirradiated solution. Chemical name used: ferric diethylenetriaminepentaacetic acid (FeDTPA).
We assessed variable chlorophyll fluorescence (Fv/Fm) and needle chlorophyll concentration of seedlings of Maccedonia fir (Abies borisii regis Mattfeld), subalpine fir [A. lasiocarpa (Hooker) Nuttall], Sakhalin fir [A. sachalinensis (Schmidt) Mast.], Siberian fir [A. sibirica (Lebed.)], and Veitch fir (A. veitchii Lindl.) grown under varying soil media pH. Soil media pH was modified using liquid flowable dolomitic limestone, resulting in five pH levels (3.4, 4.0, 5.4, 6.0, and 6.8). Increasing media pH significantly reduced Fv/Fm and needle chlorophyll concentration in all of the species tested. The effect of pH on photochemistry was due to depressed nutrient uptake of P, Mn, B, and Cu. Because photosynthetic quantum yield may be related to deficiencies of several elements affected by pH, Fv/Fm may serve as a criterion to select for improved pH tolerance. Among the species examined, A. veitchii and A. lasiocarpa were most tolerant of increased pH based on Fv/Fm and needle chlorophyll concentration.