The Pivotal Role of Phenological Stage Enhanced by Plant Origin Preparations in the Process of Rhizogenesis of Rosa ‘Hurdal’ Stem Cuttings

Some biostimulants, including plant origin preparations, act similarly to plant hormones. Moreover, the supplementation of known and unknown rooting cofactors can stimulate rhizogenesis in cuttings. The aim of this research was to assess the response of difficult-to-root and long-rooting stem cuttings of the once-blooming old variety Rosa ‘Hurdal’ to preparations of plant origin. The hypothesis was that plant origin preparations could enhance rooting processes by inhibiting chlorophyll a/b degradation in leaves and postponing leaf senescence, simultaneously increasing the quality of cuttings. The one-bud stem cuttings were made in four phenological stages: (H1) flower buds closed, (H2) open flowers, (H3) just after petal fall, (H4) 7-14 days after petal shedding. They were treated with either standard commercial powder preparations containing 0.4% indolebutyric acid (IBA) or 0.2% naphthalene acetic acid (NAA) as well as with commercial plant origin preparations that this work will henceforth refer to as: Algae Extract, Organic Preparation, and Plant Extract. The cuttings were evaluated after 12 weeks of rooting them in two substrates: peat-perlite and peat-sand (v:v; 1:1). Mean root percentages for both substrates were noted after preparation from stage H1 (74.5 %), H2 (59.5 %), H3 (50.8 %) shoots. The H4 cuttings didn’t root at all and were not considered further. The means for all phenology stages together were the highest by the use of 0.6 % Algae Extract, 0.012 % and 0.02 % Organic Preparation, 0.2 % and 0.4 % Plant Extract. The lowest means were reported for the control cuttings as well as NAA and IBA treatment. Plant origin preparations encouraged growth parameters but did not unequivocally inhibit the decrease of chlorophyll content in the cuttings’ leaves. Rooting percentage depended on the quality of cuttings as well as chlorophyll a/b and soluble protein content in leaves in both rooting substrates.

Minicutting technique and IBA application in vegetational propagation of Schinus terebinthifolia Raddi

Vegetative propagation is an alternative for the production of seedlings of native tree species such as Schinus terebinthifolia that presents a high predation rate on its seeds. In order to develop vegetative propagation technology, different concentrations of indolebutyric acid (IBA) were tested in the rooting of apical and intermediate minicuttings of Schinus terebinthifolia. The 2x4 factorial experimental design involved two types of minicuttings (apical and intermediate) and four dosages of the hormone IBA (0, 1000, 2000, and 4000 mg. L-1). The percentages of survival and rooting were evaluated. The intermediate minicuttings (37% and 35%) showed significantly greater survival than the apical cuttings (22% and 9%) respectively at 30 and 60 days, regardless of the IBA concentration. Among the rooting averages at 60 days obtained in the different concentrations of IBA, the treatment of 4000 mg. L-1 generated the highest results (9% for apical and 35% for intermediate). The vegetative propagation by minicuttings of Schinus terebinthifolia demonstrated the viability of intermediate minicuttings with high rooting associated with the highest concentration of IBA.

Light spectrum and indolebutyric acid (IBA) in rhizogenesis in herbaceous cuttings of guava trees

Background: In the production of seedlings, success in the market is due to a quality product. Well-developed seedlings with a good root system, appear as a key factor to guarantee suitable products. Light can be used as a stimulating factor for rooting, in adequate light quality. Photoselective screens can be used to make rooting more efficient. Methods: To evaluate this factor, herbaceous cuttings of Guava Tree “Paluma” were used, exposed to different wavelengths in mini-greenhouses covered with cellophane of the colors: green, yellow, red, blue, transparent and orange, and subjected to five treatments with Indolebutyric Acid (IBA) (0, 1000, 2000, 3000 and 4000 mg.kg-1), grown in a 3: 2: 1 substrate (sand: earth: bioplant®), in a randomized block design, with a 6x5 factorial and four replications with 10 cuttings in each treatment. Ninety days after staking, the following variables were evaluated: cuttings survival, number of leaves; number of sprouts; largest sprout length; root length; root volume; green mass of leaves and root; dry mass of sprout and root. Results: The orange and red light spectra were superior in rooting the guava cuttings, and may be an option in covering the seedling production nurseries of this fruit tree. Conclusion: The use of IBA neutralized the luminous influence of the light spectra with non-significant results for the interaction.

Differential Effects of Exogenous Glomalin-Related Soil Proteins on Plant Growth of Trifoliate Orange Through Regulating Auxin Changes

Multiple functions of glomalin released by arbuscular mycorrhizal fungi are well-recognized, whereas the role of exogenous glomalins including easily extractable glomalin-related soil protein (EE-GRSP) and difficultly extractable glomalin-related soil protein (DE-GRSP) is unexplored for plant responses. Our study was carried out to assess the effects of exogenous EE-GRSP and DE-GRSP at varying strengths on plant growth and chlorophyll concentration of trifoliate orange (Poncirus trifoliata) seedlings, along with changes in root nutrient acquisition, auxin content, auxin-related enzyme and transporter protein gene expression, and element contents of purified GRSP. Sixteen weeks later, exogenous GRSP displayed differential effects on plant growth (height, stem diameter, leaf number, and biomass production): the increase by EE-GRSP and the decrease by DE-GRSP. The best positive effect on plant growth occurred at exogenous EE-GRSP at ½ strength. Similarly, the GRSP application also differently affected total chlorophyll content, root morphology (total length, surface area, and volume), and root N, P, and K content: positive effect by EE-GRSP and negative effect by DE-GRSP. Exogenous EE-GRSP accumulated more indoleacetic acid (IAA) in roots, which was associated with the upregulated expression of root auxin synthetic enzyme genes (PtTAA1, PtYUC3, and PtYUC4) and auxin influx transporter protein genes (PtLAX1, PtLAX2, and PtLAX3). On the other hand, exogenous DE-GRSP inhibited root IAA and indolebutyric acid (IBA) content, associated with the downregulated expression of root PtTAA1, PtLAX1, and PtLAX3. Root IAA positively correlated with root PtTAA1, PtYUC3, PtYUC4, PtLAX1, and PtLAX3 expression. Purified EE-GRSP and DE-GRSP showed similar element composition but varied in part element (C, O, P, Ca, Cu, Mn, Zn, Fe, and Mo) concentration. It concluded that exogenous GRSP triggered differential effects on growth response, and the effect was associated with the element content of pure GRSP and the change in auxins and root morphology. EE-GRSP displays a promise as a plant growth biostimulant in citriculture.

Effects of phosphorus, indolebutyric acid and naphthylphthalamic acid on the lateral root growth of Poncirus trifoliata

To explore the influence of phosphorus (P), indolebutyric acid (IBA, Auxin) and Naphthylphthalamic acid (NPA, Auxin transport inhibitor) on plant lateral root (LR) formation, Poncirus trifoliata seedlings at two P levels, low P (LP) and control treatment (CK), which was applied with IBA and NPA, and the regulative effects of P level, IBA and NPA on LR formation of trifoliate orange were investigated. The results showed that LP level significantly reduced the plant biomass, LR number and length. NPA significantly decreased the plant biomass, LR number and length, while IBA did not significantly influence these parameters. These data suggested that auxin signaling pathway could be involved in the regulation of P level on LR formation, and the auxin transportation should be the key factor in LR formation of trifoliate orange.

Acacia Mangium × A. Auriculiformis Micropropagation in a Non-Sterile Environment

Background: Autoclaving is used to eliminate contamination during tissue culturing, however, it is a complicated process, time-consuming and costly. Chemical sterilization of tissue culture can effectively eliminate contamination, is a simple procedure, and cost effective. However, studies on the chemical sterilization mostly focus on bud induction, while the effects of chemical sterilization overall process of tissue culture, including bud induction, proliferation, and rooting, remain to be determined. Here, we investigate the effect of chemical sterilization on bud induction, proliferation, and rooting of Acacia mangium × A. auriculiformis.Results: The results showed that chlorothalonil (0.2 g/L) was a suitable chemical sterilant, and bud induction medium was 1/8 Murashige and Skoog medium + agar 7 g/L + chlorothalonil 0.2 g/L + 6-benzylaminopurine 0.5 mg/L The highest induction rate (99.54%) was observed in the third to fifth buds’ stem segments collected in October treated with 0.8 g/L carbendazim for 3 min, with a contamination rate of 0. The rooting medium was agar 7 g/L + chlorothalonil 0.2 g/L+ indolebutyric acid 1.5 mg/L + naphthylacetic acid 0.5 mg/L, and the rooting rate was 97.62%. The proliferation rate and subculture duration showed a positive correlation, while the proliferation rate was 3.58 times higher at the fourth subculture rooting. Conclusions: Our results suggest that chlorothalonil can effectively replace autoclaving during bud induction, proliferation, and rooting of A. mangium × A. auriculiformis. The findings of this study provide technical support for rapid seedlings propagation, accelerates the breeding process of Acacia, and can be applied in other tree species.

Effects on Plant Hormone levels at Different Growth Stages in Diverse Grape Organs with Root Restriction

Endogenous plant hormones play important roles in germination, blossom, senescence, abscission of plants by a series of signal transduction and molecular regulation. The purpose of this research was to investigate the influence of root restriction (RR) cultivation on plant hormones variation tendency at different growth stages in diverse organs or tissues, ‘Muscat Hamburg’ (Vitis ‘Muscat of Alexandria’ × Vitis ‘Trollinger’) grapevine was used as test material. High Performance Liquid Chromatography (HPLC) was used to quantify hormone levels, aiming to investigate the influence of root restriction on the formation and transportation of plant hormones. The results revealed that RR treatment increased abscisic acid, salicylic acid, zeatin riboside, N6-(delta 2-isopentenyl)-adenine nucleoside concentrations, while reduced auxin, 3-indolepropionic acid, 3-indolebutyric acid, gibberellin A3, zeatin, N6-(delta 2-Isopentenyl)-adenine, kinetin, jasmonic acid and methyl jasmonate concentrations. To sum up, our results suggested that RR treatment could initiate stress responses via up-regulating abscisic acid and salicylic acid contents while down-regulating auxin and kinetin contents, resulting in the changes of fruit appearance and improvement of berry quality.

Rooting of Schinus terebinthifolia Raddi Cuttings as a Function of the Preparation Method and Indolebutyric Acid Concentrations

Schinus terebinthifolia Raddi, popularly known in Brazil as pink pepper or aroeira, has become a new source of agricultural exploitation for some farmers, notably located in the north of the state of Espírito Santo, the largest producing region in the world. Once it was a species that has been historically exploited in an extractive manner, where only what nature offers is explored, the need for the generation of scientific knowledge to understand its genetic potential in all agronomic areas is evident, starting with the large spread in scale of this species. Therefore, the objective of the work was to study the effects of indolebutyric acid (IBA) on the physiology and quality of seedlings produced by cuttings of the species Schinus terebentifolia Raddi under different concentrations of this hormone and different ways of application. The experiment design was a factorial in randomized blocks, in the 2x7 arrangement, the first being composed of two forms of preparation of the hormone (dilution in acetone or in water) and the second composed by 7 concentrations of IBA (0 mg/L; 625 mg/L; 1250 mg/L; 2500 mg/L; 3000 mg/L; 3750 mg/L and 5000 mg/L) with 5 blocks and 5 plants in each treatment. The addition of IBA favored the development and physiological aspects of the seedlings, produced from the hormone prepared with both, water and acetone. The quality of seedlings induced with IBA diluted in water was compromised with the addition of the hormone, whereas in seedlings treated with IBA diluted in acetone, the estimated dose of 1750 mg/L of IBA, promoted the better quality index (IQD) of the seedlings.

Substrate and indolebutyric acid in the rooting of pomegranate cuttings collected in two seasons

The pomegranate (Punica granatum L.) presents potential for commercial exploitation as a fruit, ornamental or medicinal plant. However, for its usage in orchards, it is ideal that the seedlings come from vegetative propagation techniques. The aim of this work was to test the usage of indolebutyric acid (IBA) and substrates, at two harvesting times (before and after fruiting) in the cutting propagation of pomegranate. The work was carried out at UTFPR, Campus Dois Vizinhos. The experiments were installed in a randomized block design, in a 4 x 4 factorial scheme (IBA concentration x substrate), with four replications and ten cuttings per experimental unit. IAB was tested at concentrations 0; 1000; 2000 and 3000 mg L-1. The used substrates were Red Latosol, medium textured sand, commercial substrate MecPlant® and a mixture of Red Latosol + sand + commercial (1:1:1, v/v). The cuttings were placed in beds in a screened protected environment, with 50% shading. Irrigation was performed three times a day for 30 min., by a micro sprinkler. After 60 days, rooting (%), cuttings with callus (%), number of primary leaf and root shoots, length of the three largest roots and percentage of dead cuttings were evaluated. Cutting presented itself as a potential technique to be adopted for pomegranate, using sand, with the use of IBA at concentrations between 1600 and 1750 mg L-1. Cuttings must be collected before fruiting. However, rhizogenesis close to 50% was achieved at the time after such phenological stage.