EFFECT OF POULTRY LITTER BIOCHAR ON THE NUTRITIONAL STATUS OF CORN1

ABSTRACT Corn, one of the main grain crops in Brazil, needs to have its nutritional requirements fully satisfied to achieve high biological productivity. Thus, the objective of this work was to evaluate the influence of increasing doses of poultry litter biochar on nutrient concentrations in the leaves of hybrid corn BRS 2022 and in the soil after harvest. The experiment was carried out in a completely randomized design, with four replicates, evaluating six doses of biochar (0; 2.02; 4.05; 6.07; 8.10 and 10.12 t ha-1) and the plots composed of one plant per pot with a volume of 20 dm3. The collection of leaves for leaf diagnosis was carried out at the time of flowering, removing the opposite leaf from the ear base in the middle third region. These leaves were dried in a forced air circulation oven, 65 °C, for a period of 48 hours, ground, sieved through 20 mesh and analyzed for the concentrations of macronutrients in the leaf tissue. At the end of the experiment, 83 days after corn sowing, soil samples were collected as a function of the treatments and then analyzed chemically. Biochar application promoted an increase in the leaf contents of N, P and K, resulting in improvements in the nutritional status of plants for these nutrients. The chemical characteristics of the soil, analyzed after the corn harvest, revealed that there was an influence of the doses of biochar on the levels of calcium, organic carbon, potassium and phosphorus.

Expression of a mutant maize gene in the ventral leaf epidermis is sufficient to signal a switch of the leaf’s dorsoventral axis

Maize leaves are initiated from the shoot apex with an inherent leaf dorsoventral polarity; the leaf surface closest to the meristem is the adaxial (upper, dorsal) surface whereas the opposite leaf surface is the abaxial (lower, ventral) surface. The Rolled leaf1 (Rld1) semi-dominant maize mutations affect dorsoventral patterning by causing adaxialization of abaxial leaf regions. This adaxialization is sometimes associated with abaxialization of the adaxial leaf regions, which constitutes a ‘switch’. Dosage analysis indicates Rld1 mutants are antimorphs. We mapped Rld1’s action to a single cell layer using a mosaic analysis and show Rld1 acts non cell-autonomously along the dorsoventral axis. The presence of Rld1 mutant product in the abaxial epidermis is necessary and sufficient to induce the Rolled leaf1 phenotype within the lower epidermis as well as in other leaf layers along the dorsoventral axis. These results support a model for the involvement of wild-type RLD1 in the maintenance of dorsoventral features of the leaf. In addition, they demonstrate the abaxial epidermis sends/receives a cell fate determining signal to/from the adaxial epidermis and controls the dorsoventral patterning of the maize leaf.

TRANSLOCATION AND PERSISTENCE OF TOPICALLY APPLIED DIAZINON AND PHORATE IN BEANS

Diazinon (O,O-diethyl O-(2-isopropyl-6-methyl-4-pyrimidinyl)phosphorothioate) and phorate (O,O-diethyl S-[(ethylthio)methyl] phosphorodithioate) were each applied to one leaf of each of 48 bean (Phaseolus vulgaris L.) plants to trace translocation and persistence within the growing plant. Both insecticides moved readily from the treated leaf to the opposite leaf and upward into the shoot. Residues appeared in the stem, but downward movement into the roots was limited. With diazinon, only the parent compound was recovered; with phorate, the sulfoxide and sulfone metabolites were the major fractions after the 1st day. By 14 days after treatment, total residues of phorate and its metabolites had diminished to 0.02 ppm or less, except in the treated leaf itself; diazinon levels had decreased to 0.02, 0.04, and 0.08 ppm in the untreated leaf, stem, and shoot, respectively.

Retardation of leaf senescence by benzyladenine in bean plants is not dependent on mobilization

Application of benzyladenine (BA) to portions of a bean leaf either along or across the midvein or to one of the two primary leaves, on intact plants, retarded senescence of the treated part. When 14carbon labeled CO2, IAA, leucine, or sucrose was fed to the untreated part on the same leaf, or to the untreated opposite leaf, there was less than 2% of the total radioactivity in the BA treated part after 24 h. It is concluded that retardation of leaf senescence by BA on intact bean plants is not dependent on mobilization of metabolites from other parts of the leaf.

The Effect of Water Stress On [14c]Sucrose Transport in Bean Plants

The passage of 14C through stressed and control bean seedlings has been followed after supply of [14C]sucrose to a primary leaf. The course of synthesis of [14C]sucrose into non-ethanol-soluble compounds in the various plant parts was also investigated. Concomitant measurements of relative turgidity were made either on part of the 14C-treated leaf or on the twin opposite leaf.