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  • Author or Editor: C. K. Labanauskas x
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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