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- Author or Editor: C. K. Labanauskas x
Major nutrients removed by ‘Valencia’ orange fruit were N, K, Ca, P, and Mg. Amounts of N, Ca, and B were higher; Zn and Mn were lower than those reported for Florida oranges. Relatively small amounts of applied nutrients were found to be removed by the fruit. P, K, Ca, Mg, Zn, Mn, Cu, and Fe tended to be immobilized in the soil (either by direct application or decay of leaves and other plant parts), availability depending on soil pH. Leaching of N, largely as NO3, should always be minimized.
Using wet-digestion as a standard, leaf samples of orange (Citrus sinensis (L.) Osbeck cv. Valencia) and Schefflera actinophylla Harms were dry-ashed at 500° and 700°C to demonstrate analytical sensitivity of the Schefflera nutrient elements to ashing temperature. Citrus leaf samples dry-ashed at 500° showed only a significant analytical loss in Fe, but dry-ashing at 700° showed substantial losses in Zn, and K. Schefflera leaf samples dry-ashed at 500° showed substantial losses in Cu, Fe, and Mn. Samples dry-ashed at 700° showed high to very high losses in Ca, Mg, Na, Zn, Cu, Mn, and Fe. Use of an analytical method established for one plant species was clearly not applicable to others without verification.
Zn and K loss was related to increasing temperature, and Cu, Fe, Mg, and P loss was related to the residual carbon in the ash of a standard routine check and reference sample of ‘Valencia’ orange leaves (Citrus sinensis (Linn.) Osbeck). Only Zn showed both loss due to volatilization and analytical loss related to increasing amounts of residual carbon. Mn and Na did not show a clear response to time, temperature, or sample size; B showed a response only at the highest temperature. The magnitude of differences was small, but the measured differences were very highly significant, indicating consistency due to treatment under given sets of conditions.
In a proven dry-ashing procedure widely accepted for citrus leaves in California, best results were obtained when citrus tissue materials were ashed at 550°C for 8 hr, and when sample size was not greater than 2.5 g.
It was clearly demonstrated that rootstocks have a strong influence on nutrient concentrations in scion leaves. The concentrations of Cl and B in leaves from ‘Valencia’ trees on several trifoliate orange rootstocks were 56% and 43%, respectively, higher than in leaves from trees grown on sweet orange rootstock.
The concentration of nutrients in leaves from trees grown on sweet orange rootstocks were not affected by Rubidoux trifoliate (C), Rubidoux trifoliate (A), English small trifoliate, Benecke trifoliate, and Jacobsen trifoliate interstocks.
Samples were taken from grapefruit Citrus paradise Macf. cv. Marsh, Valencia orange Citrus sinenesis L. Osbeck, and lemon Citrus limetta, ‘Risso’ trees growing in the field in the Citrus Research Center, Riverside, California. Quantitation of 17 protein and 18 nonprotein amino acids of citrus leaves were evaluated for comparative effects of sample drying-methods on the 3 citrus species.
Freeze-dried leaves contained significantly higher amounts of nonprotein, and lower amounts of protein amino acids, than the analogous leaves that were oven-dried. This indicates that citrus leaves must be enzymatically deactivated immediately after sampling and kept in a frozen condition in preparation for analysis. Otherwise, accurate assessment of amino acids in the leaves at sampling would not be obtained.
Grapefruit and ‘Valencia’ orange leaves contained higher concentrations of glutamic acid, aspartic acid, leucine, lysine, and arginine than of other protein amino acids. Lemon leaves contained more substantial amounts of glutamic acid, arginine, aspartic acid, leucine, and glycine.
The nonprotein amino acids proline, serine, alanine, and aspartic acid were found in more substantive amounts in grapefruit and ‘Valencia’ orange leaves, 77 and 69 percent, respectively, of the sum of nonprotein amino acids determined. In lemon leaves, proline, arginine, lysine, serine, and alanine were found to be more concentrated. These 5 nonprotein amino acids constituted 79% of the total of those determined. Proportionally, lemon leaves contained a larger fraction of nonprotein amino acids than grapefruit or ‘Valencia’ orange leaves.
The effects of Fe-deficiency and Mn-deficiency in macadamia leaves on the accumulation of free amino acids and total amino acids (free plus protein amino acids) were studied in water vs. sand culture. Leaves showing severe Fe-deficiency symptoms contained substantially higher concentrations of free histidine, aspartic acid, threonine, serine, glutamic acid, proline, alanine, valine, and tyrosine than analogous control leaves. The sum of the individual free amino acids were 177% higher in the Fe-deficient leaves than in the control leaves.
Mn-deficient leaves, containing .0003% Mn, had significantly higher concentrations of free aspartic acid, threonine, glutamic acid, proline, alanine, valine, isoleucine, leucine, tryosine, and phenylalanine than analogous control leaves. The sum of the free amino acids in Mn-deficient leaves was 85% higher than in the analogous leaves from the control plants.
In chlorotic Fe-deficient leaves the concentrations of total lysine, histidine, ammonia, arginine, aspartic acid, methionine, and leucine were significantly higher than in control leaves.
Mn-deficient leaves contained significantly higher amounts of total lysine, histidine, ammonia, aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine and phenylalanine than control leaves.
The concentrations of free lysine, histidine, aspartic acid, glutamic acid, proline, alanine, and valine were higher in the leaves of plants grown in sand culture. The total ammonia, threonine, methionine, leucine, tyrosine, and phenylalanine were lower in the leaves of plants grown in water culture. Total arginine was higher in leaves from the sand culture.
There were several significant interactions between treatments and culture media on the accumulation of free and total amino acids in the Fe- or Mn-deficient leaves.
Three-year-old seedlings of Cleopatra mandarin (Citrus reticulata Blanco) and Troyer citrang [Citrus sinensis (L.) Osbeck × Poncirus trifoliata (L.) Raf] were budded to ‘Valencia’ orange (Citrus sinensis (L.) Osbeck) at 5, 15, 30, 45, 60, and 90 cm above the ground level. Fruit yield was highest from trees budded at 15 cm height above the ground and tended to decrease as budding height increased. Nutrient concentrations in the leaves of trees were affected by the height of budding, but remained in an optimum range for maximum fruit production. The different rootstocks affected the nutrient concentrations in the leaves dramatically, but they still remained in an optimum range for maximum production of oranges.
Citrus leaves from plants supplied with low soil oxygen showed a decreased sum of protein amino acids, while the free amino acids sum increased. Leaves from Phytophthora spp. infested plants contained a higher free amino acids sum than uninfested. The orange leaves, Citrus sinensis L. Osbeck cv. Atwood navel, contained a higher sum of protein amino acids than lemon leaves, Citrus limon L. Burm. cv. Prior Lisbon, although both of these species were budded on sweet orange rootstock, Citrus sinensis L. Osbeck cv. Bessie. Leaves from the orange scion contained lower concn of glutamic acid, glycine, valine, isoleucine, and leucine, and higher aspartic acid and phenylalanine than the lemon leaves. The sum of the free amino acids in the orange leaves was higher than in lemon leaves. Significant interaction effects on free cystine, methionine, and tyrosine were caused by Phytophthora spp. infestation in the 2 species.
Tomato plants (Lycopersicon esculentum Mill.) were grown to maturity in complete nutrient solution with osmotic potentials (sψo) of −0.8, −2.4, −4.4 and −6.4 bars from NaCl additions, and 0.5, 5.0, and 50 ppm P as variables. The objectives were to evaluate the effects of sψo and P and their interactions with respect to fruit yield and quality, and nutrient concentrations in the plants and fruits. Reducing the sψo (increasing negative values) by NaCl addition significantly decreased tomato fruit yield, but increased the percentages of soluble solids, total solids, blossom-end rot (BER) incidence and non-marketable fruit. Increased solution salinity resulted in higher leaf concentrations of P, Na and Cl. Increased nutrient solution P levels (Ps) significantly increased fruit yield, but decreased the percentage of fruit soluble solids and BER incidence. Leaf P, Ca and Cl concentrations of plants grown in the high P nutrient solution were higher than those of the leaves from low P solution plants. The incidence of BER was greatest under low sψo and low Ps. Reduced Ca concentrations of leaves and mature fruit were associated with the BER development. The Ca concentration of mature normal fruit varied from 0.039 to 0.076% compared with 0.028 to 0.043% for mature BER fruit. Leaf Ca concentrations of 1.5 to 2.0% were associated with the BER condition.
The effects of 2 rootstocks of avocado (Persea americana Mill.), 2 soil oxygen levels, and 2 soil moisture levels on nutrient uptake and translocation showed that seedling Duke and Topa Topa rootstocks produced little change in the growth of ‘Hass’ scion, nutrient concentrations in the leaves, stems, and roots or the total amount of nutrients absorbed per plant. Total amounts of 11 nutrients studied were significantly lower, irrespective of concentrations found in the various plant tissues, in plants grown in with 2% soil oxygen than in plants supplied with 21% soil oxygen. Low soil moisture reduced dry weights of leaves and stems, and total dry weight of plants. Total amounts of N, P, K, Ca, Mg, Zn, and Mn per plant, irrespective of nutrient concentrations in the leaves, stems, and roots, were significantly lower in plants grown under low soil moisture.