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  • Author or Editor: C. K. Labanauskas x
  • Journal of the American Society for Horticultural Science x
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Abstract

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.

Open Access

Abstract

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.

Open Access

Abstract

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.

Open Access

Abstract

The comparative analysis of leaf-oil components separated by vapor phase chromatography was tested on stubborn infected and non-infected sweet orange leaves as a possible new technique for detection of stubborn disease of citrus. Three leaf-oil components: citronellol, nerol, and geraniol were found reduced in the stubborn infected leaves, but the reduction was shown to be related to the smaller leaf size and not due to the stubborn pathogen. However, one component, linalool, showed an increase in stubborn or stunt infected leaves relative to respective controls. This increase was not related to leaf size, but probably due to the presence of the pathogen.

Open Access

Abstract

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.

Open Access

Abstract

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.

Open Access

Abstract

Protein amino acids in leaves of Phytophthora spp.-infested or noninfested plants were not affected measurably. Leaves from plants supplied with low soil oxygen levels contained significantly less protein amino acids: lysine, histidine, aspartic acid, threonine, serine, glutamic acid, glycine, alanine, valine, isoleucine, leucine, tyrosine, and phenylalanine but more arginine than analogous leaves of plants supplied with normal soil oxygen concn.

The leaves of Phytophthora-infested plants contained significantly lower concn of nonprotein amino acids: threonine, glycine, alanine, cystine, valine, methionine, isoleucine, leucine, tyrosine, and phenylalanine but higher concn of arginine and aspartic and glutamic acids. The nonprotein amino acids: lysine, arginine, aspartic acid, and pro line were higher, while threonine and glutamic acid were lower, in seedling leaves supplied with low soil oxygen than those in leaves on plants supplied with normal soil oxygen.

The protein and nonprotein proline, and the sum of nonprotein amino acids increased in leaves of noninfested plants, while decreasing in leaves of infested plants, with a decreasing level of soil oxygen to roots.

Substantive amounts of protein amino acids found in citrus seedling leaves were glutamic acid, aspartic acid, proline, leucine, and arginine; those of nonprotein amino acids were proline, arginine, serine, lysine, and aspartic acid. These amounts represent, respectively, 50 and 90% of the sum.

Open Access

Abstract

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.

Open Access

Abstract

Seedlings of ‘Topa Topa’ avocado (Persea americana Mill.) were grown in steamed loamy sand soil with no fertilizer, complete fertilizer (N, P, K, S, Ca, Mg, Cu, Zn, Mn, Fe, Mo, B), −P, −Zn, −P and −Zn, and −Zn+10 × P(640 ppm P). Seedlings were inoculated separately with one of 2 isolates of Glomus fasciculatus (Thaxter) Gerd. & Trappe (GF) or were inoculated with a water filtrate of the mycorrhizal inoculum plus autoclaved mycorrhizal inoculum. Growth of mycorrhizal seedlings was 49-254% larger than nonmycorrhizal avocados except at the −Zn+10×P regime where mycorrhizal and nonmycorrhizal avocados were of similar size. Both mycorrhizal isolates increased absorption of N, P, and Cu at all fertilizer treatments and absorption of Zn was increased with all fertilizer treatments by one mycorrhizal isolate. Fertilization with P did not alter P concentrations in leaves of nonmycorrhizal plants but increased P concentrations in leaves of mycorrhizal seedlings. Fertilization with 10×P increased P concentrations in both mycorrhizal and nonmycorrhizal seedlings. One GF isolate appeared to be superior to the other based on mineral nutrition of the host avocados. Differences between the isolates apparently were related to their rate of growth or ability to infect. Poor growth of avocado seedlings in steamed or fumigated soil can be related to poor mineral nutrition due to the destruction of mycorrhizal fungi.

Open Access

Abstract

Oil, corresponding in amount to 6-14% of the original nut weight, was extracted from intact macadamia kernels by immersing them in petroleum ether for 48 hours at room temperature. Drying the extracted nuts in a vented oven at 55°C for 24 hours removed the odor and taste of the solvent and their flavor seemed to equal or excel that of nonextracted nuts. Oil thus recovered and marketed could provide additional revenue to the macadamia industry. Nuts of M. tetraphylla and of M. integrifolia were equal in oil content (74.9%) with an iodine value of 71.8 and 75.4, respectively. Macadamia oil had outstanding stability. The 8 major fatty acids in the oil and their mean percentages in the 2 species and their F1 and F2 hybrids were: myristic (0.60), palmitic (8.7), palmitoleic (22.1), stearic (3.6), oleic (59.1), linoleic (1.8), arachidic (2.2), and eicosenoic (1.5). The mean protein content in the lipid free meal of the parental and F1 populations was 36.5%. Arginine, aspartic acid, glutamic acid, and leucine made up about 52% of total amino acids recovered in each of the 2 species and the F1 generation.

Open Access