ABSTRACT The usual propagation method for Dalbergia nigra is via seedings; however, the seasonal supply has a variable quantity of seeds which limits the continuous production of seedlings. Therefore, the objective of this study was to establish a vegetative propagation protocol via mini-cuttings technique for D. nigra from juvenile shoots obtained from seedlings. The experimental design was completely randomized in a 2 x 2 x 4 factorial scheme, with two geographical origins: two controlled release fertilizer doses (4.0 and 8.0 g.dm-³) and four indole-3-butyric acid (IBA) concentrations (0; 2,000; 4,000; and 6,000 mg.Kg-1), with four replications. The mini-cuttings were removed from the tubes after 60 days of propagation in the greenhouse, and the substrate was completely removed by washing in running water to observe the roots. The survival percentage, rooting, rooting speed and variables related to mini-cuttings vigor (largest root length (RL, cm.plant-1), number of roots (NR), surface area (SA, mm2), root volume (RV, mm³) and root dry mass (RDM, g.plant-1) were measured. The results indicated that D. nigra has an aptitude for vegetative propagation by mini-cuttings with survival values and rooting greater than 70%. Geographical origins present a different set of responses for survival, rooting and vigor of mini-cuttings. Stock plant nutrition influences mini-cuttings root growth. IBA concentrations did not promote an effect on the mini-cuttings rooting percentage; however, exogenous auxin at the dose of 6,000 mg.Kg-1 provided mini-cuttings with greater vigor in their radical system. Nonetheless, further research is suggested to define the feasibility of using this regulator in the vegetative propagation of this species.

ABSTRACT Paratecoma peroba is a native forest species of great economic and ecological interest, currently at risk of extinction. In addition to the difficulty of finding adult individuals of this species, plant production is limited, so the use of mini-cuttings can facilitate the spread of P. peroba. Thus, the objective of this study was to analyse the effect of different doses of controlled release fertilizer (CRF) on rooting, growth, photosynthetic metabolism and nutritional balance of P. peroba clones propagated by mini-cuttings. Five doses of CRF (0, 2, 4, 6 and 8 kg.m-3) were tested, arranged in a completely randomized design with 12 repetitions and each repetition consisted of eight clones. Evaluations were carried out in the three stages of clones production: 1) Survival at 60 days in a greenhouse, 2) Rooting at 105 days in a shade house; and 3) Evaluation Productivity index, morphological variables, physiological metabolism, and nutritional through macronutrient contents, diagnosis and recommendation integrated system (DRIS) indices and the average nutritional balance index of clones at 120 days in the area of hardening. There was no influence of CRF on survival and rooting of mini-cuttings. The CRF favoured a higher productivity index, vegetative growth and physiological activity of the clones. The 6 kg.m-3 dose was sufficient to obtain nutritionally balanced clones.

ABSTRACT Paratecoma peroba is a native Brazilian forest species of great economic and ecological interest, which is currently at risk of extinction owing to excessive wood exploration. The use of the mini-cutting technique could facilitate the vegetatively propagation of this species. The objective of the present study was to establish a vegetative propagation protocol for P. peroba using the mini-cutting technique. In the first experiment, were tested five concentrations of indolbutiric acid (IBA; 0, 1, 2, 4 and 8 g.L-1) and two types of substrates (sand and a commercial substrate based on ground Pinus bark, coconut powder, and mineral additives). In the second experiment, were tested three types of mini-cuttings (apical of 6 cm and 10 cm, and intermediary of 4 cm) and two leaf area sizes (total leaf area and reduced to 50% of leaf area). The results showed that P. peroba could be vegetatively propagated using the mini-cutting technique with up to 82.5% rooting. There was only 5.6% of mini-cutting rooted in sand. High concentrations of IBA promotes decrease in rooting and number of roots. The 10 cm apical mini-cuttiing tend to form clones with better quality standards. The maintenance of the leaf area promotes the attainment of roots with greater root surface area, volume and dry mass of P. Peroba plants.

ABSTRACT Melanoxylon brauna is a tree species native to the Atlantic Forest of high ecological and economic value. The objective of this study was to evaluate the growth and nutritional status of seedlings of two Melanoxylon brauna cultivars grown in substrate with different controlled-release fertilizer doses (CRF). The experiment was arranged in a randomized block 4 × 2 factorial design, with four CRF doses (0, 2, 4, and 8 kg m-3) and two seed origins (Viçosa-MG and Linhares-ES), with four replicates and 126 seedlings per plot. At 60, 90, and 120 days after emergence, seedlings were collected to measure variables related to emergence, growth, and nutrition. The greatest growth and best nutritional status were found for seedlings originated from seeds collected in Linhares at CRF dose of 8 kg m-3. On the other hand, seedlings originated from seeds collected in Viçosa showed low emergence and high plant mortality.