Propagation Of Seedlings Research Articles

Method of opening the fruits, biometry and anatomical description of embryonic development in pau-branco (<i>Cordia oncocalyx</i> Allemão) seeds

The tree species Pau-branco, Cordia oncocalyx Allemão has great economic potential, especially for logging, but its extraction is uncontrolled and can cause depredation. This type of harvest does not guarantee sufficient raw material to supply the demanding sectors such as furniture industries. The propagation of the species in plant nurseries starting from fruits and seeds could offer a solution to this problem. However, the fruits obtained from native plants comprise different sizes and different degrees of ripeness, making germination and propagation processes a difficult task. Knowledge of the final zygotic embryogenesis (fruit phase) anatomy is very important to establishing a propagation protocol for this species, especially to achieve a successful seed rescue of those containing mature zygotic embryos. The objectives of the present work was to establish a method to open the fruits and to study the microstructure and anatomy of the embryo in seeds of pau-branco, never shown before, with the goal of determining in which phase of development seed rescue is most appropriate for subsequent planting and seedling propagation. Mature fruits of pau-branco at different developmental stages were collected and subjected to microscopic investigation or biometrics determination. Transverse and longitudinal sections were obtained and processed for optical and scanning electron microscopy for the anatomical description of fruits and seeds. It was observed that the fruit has an exocarp and mesocarp. The mesocarp is divided into a sub exocarp-like mesocarp and a sclerenchymatous mesocarp, the latter of which gives hardness and rigidity to the fruit. The embryo, generally approximately 1.5 cm, is visible inside the fruits. When the embryo reaches 2.0 cm, it is considered fully developed, and it is recommend that excision can take place at this stage. the use of a hydraulic press was the most viable method for the extraction of seeds from the fruits. Furthermore, it was also concluded that the embryo of pau-branco seeds contain protein reserves.

Change in Doctoral Dissertation Topics in Forest Resources from US Universities Over Four Decades

Abstract Changes in forest resources expertise from 1978 to 2017, as measured by annual number of doctoral dissertations published on twenty topics, were examined. Using the ProQuest Dissertations and Theses Global database, titles and abstracts from 11,530 dissertations produced by fifty-six universities in the United States were selected. Automated content analysis and latent Dirichlet allocation were used to identify the optimal number of topic groupings among 7,742 dissertations that met selection criteria. Substantial differences were found in the pattern of publication among the twenty topics over time. The number of dissertations related to forest growth and silviculture; tree seedling propagation, physiology, and regeneration; and forest soil nutrients, ecology, and management declined over the past two decades. Dissertations related to forest wildlife management, including terrestrial wildlife ecology and management; wildlife food and nutrition; and fish ecology and management also declined during the same period. The number of dissertations in the fields of forest policy, politics, and social science; forest modeling, biometrics, and statistics; wood science; forest vegetation ecology; and avian ecology increased during the four decades. Dissertations published in the fields of forest economics, and forest entomology and pathology, remained relatively stable. Study Implications: We found decreasing production of doctoral dissertations focused on applied forest and wildlife management topics in recent decades. Declining doctoral-level expertise in applied fields after the early 2000s suggest that there may be reduced capacity to address practical problems facing both forest and wildlife managers. This decline also suggests that finding university instructors qualified to teach more applied forest and wildlife courses may have been more difficult over the past decade and possibly into the future. Our analysis indicated that the increased number of dissertations in adjacent sciences supporting forest resources has substantially increased capacity in these areas.

An Improved and Simplified Propagation System for Pollen-Free Sugi (Cryptomeria japonica) via Somatic Embryogenesis.

Sugi (Japanese cedar, Cryptomeria japonica) is the most important forestry tree species in Japan, covering 44% of the total artificial forest area. Large amounts of pollen released from these forests each spring cause allergic reactions in approximately 40% of the population, which are a serious social and public health problem in Japan. As a countermeasure, there is an urgent need to reforest using male-sterile plants (MSPs; pollen-free plants); however, the production of MSPs via conventional methods is inefficient, time consuming, and requires considerable resources in terms of labor and space. In the present paper, we described an improved and simplified methodology for the efficient propagation of pollen-free Japanese cedar, combining the use of genetic markers (marker-assisted selection or marker-aided selection) for the early selection of male-sterile genotypes and the use of somatic embryogenesis (SE) for the clonal mass propagation of seedlings. We describe all the stages involved in the production process of somatic seedlings. Our results demonstrated that this methodology easily and efficiently produces MSPs with a discrimination rate of 100% in a short period of time. Production of 243.6 ± 163.6 cotyledonary embryos per plate, somatic embryo germination, and plantlet conversion frequencies of 87.1 ± 11.9% and 84.8 ± 12.6%, respectively, and a 77.6 ± 12.1% survival rate after ex vitro acclimatization was achieved. Moreover, we also describe an easy method for the collection of somatic embryos prior to germination, as well as an efficient and practical method for their storage at 5°C. Finally, a representative schedule for the propagation of pollen-free sugi somatic seedlings is presented as a reference for practical uses. This methodology will definitively help to accelerate the production of C. japonica MSPs across Japan.

Use of PERT (program evaluation and review technique) and PDM (precedence diagramming method) in organizing modern vegetable seedling production

Propagation of quality vegetable seedlings is a key of successful vegetable production in an open field and in protected areas. The research is aimed at the production process itself, analyzing it from technological and organizational aspects. Based on a detail calculation of time, means and costs, the researchers obtained the duration of production in days, regarding the propagation of pepper, tomato, cabbage and lettuce seedlings, taking into consideration different technological requirements of crops, ripening time, delivery time and an optimal use of the propagation area. The use of the Program Evaluation and Review Technique required more attention when making a production plan, resulting in the introduction of activities, the realization of which required only the flow of time to harmonize the monitoring of real activities. By using the Precedence Diagramming Method this problem was overcome with predefining the type of relationship between the interdependent activities (Finish-to-Start, Finish-to-Finish, Start-to-Start, and Start-to-Finish).

In vitro propagation of six selected sugarcane mutant clones through leaf explants

Six mutant clones of sugarcane with high productivity have been produced through tissue culture techniques combined with mutations using gamma-ray irradiation and Ethyl Methane Sulfonate. The six mutant clones have been tested for stability in the field. They are proven to have high productivity and yields, so that they are very potential to be developed as superior varieties. To support the planting material sufficiency of these clones, an efficient propagation method was needed. Media formulations with different physical properties and composition of growth regulators were tested to obtain high seedling propagation rates. The media formulation for callus induction was Murashige dan Skoog (MS) + 3 mg/l 2,4-D + 3 g/l casein hydrolysate + 3% sucrose and for shoot regeneration was MS + 0,5 mg/l BA + 0,1 mg/l IBA + 100 mg/l PVP and 2% sucrose. Shoot proliferation was carried out on MS liquid (1, ½) + (0.3; 0.5 mg/l) BA + 0.1 mg/l IBA + 1 mg/l Kinetin + (0; 0.5 mg/l) GA3+ sucrose 2%. The results showed that callus induction, callus regeneration, and shoot proliferation of sugarcane mutant clones were influenced by the genotype and medium composition. The fastest callus induction was obtained from the MSP-4 clone (5.82 days), and the longest was MSB-7 (8.82 days). The largest callus diameter was obtained from MSB-6 clone on MS medium containing 1 mg/l BA, 100 mg/l PVP, and 2% sucrose. The highest number of shoots was obtained from the MSB-6 clone, while the least number of shoots conducted from the MSB-8 clone. The MSB-8 clones were more difficult to regenerate compared to the others. The best media formulation for shoot proliferation was ½ MS containing 0.5 mg/l BA, 1 mg/l Kinetin, and 0.1 mg/l IBA, while the best formulation for rooting was ½ MS.

Substitution of Plastics with Organic Pots in Tree Seedlings Production for Sustainable Environmental Conservation

The Mau Forest Complex, Kenya, is the location where the study below was done with the aim of investigating if small-scale operators of tree nurseries are will to embrace and use biodegradable seedling pots. These containers include baskets made of plant fibre and bamboo tubes as well as to determine the tree species that could form a denser canopy to be used in reafforestation. This study hypothesized that biodegradable pots could promote better growth of tree seedlings and offer more environmental-friendly benefits in comparison to the extensively utilized polythene containers. Biodegradable seedling pots are options friendly to the environment compared to plastic pots commonly used in activities in the greenhouse and nurseries. The use of compostable and plantable containers based on natural and renewable materials derived from plant materials have a potential market to boost the sustainable character of current tree production systems. Three species were planted including, Hagenia abyssinica in Gatimu, Juniperus procera and Olea europea subsp. africana in Mwisho wa Lami. Basket tubes gave the highest vigor (62.429 cm) with H. abyssinica in Gatimu while bamboo (58.048cm) and control (52.667cm) did not show a significant difference at p = 0.05 level. Olea europea subsp. africana generally demonstrated higher vigor with all the applied treatments than J. procera in Mwisho wa Lami. Basket treatment gave the highest height and number of branches for the two plant species while bamboo and control treatments did not have any significant differences at p = 0.05. In this study it was found that seedling bags made from plant fibres could be adopted in tree seedling propagation to remove the synthetic plastics for sustainable environmental conservation. Hagenia abysinica was also recommended for reafforestation as it formed a quick canopy.

Production of cassava seedlings on substrates based on decomposed buriti stem

ABSTRACT In the cassava (Manihot esculenta Crantz) cultivation system, planting seedlings directly in the field is widely used. However, establishment of plants by this method is slow, taking about 15 days to start the formation of shoots and roots. The plant in this phase is not very competitive, which leads to the formation of uneven and low-productivity areas. Production of seedlings on substrates is an alternative that can improve the uniformity of the plant stand, as well as allow more careful selection of the best propagules. Viability of this propagation method depends on the substrate, which must have ideal physical and chemical properties to meet the needs of the crop. The objective of this work was to evaluate the use of decomposed buriti stem (Mauritia flexuosa L. f) as a substrate in the propagation of cassava seedlings. The substrates were composed of decomposed buriti stems and soil in the following proportions: 0:100; 20:80; 40:60; 60:40; 80:20; and 100:0 (volume). The addition of decomposed buriti stem improved development of the aerial part, provided greater survival for cassava seedlings in an increasing linear fashion, and promoted increases in the levels of N, P, K, Ca, and Mg of cassava seedlings. It was determined that there is agronomic efficiency in the use of buriti residue for the production of cassava seedlings.

Physiological and Biochemical Characterization of the GABA Shunt Pathway in Pea (Pisum sativum L.) Seedlings under Drought Stress

The physiological and biochemical role of the γ-aminobutyric acid (GABA) shunt pathway in green pea seedlings (Pisum sativum L.) was studied in response to soil water holding capacity levels: 80%, 60%, 40%, 20%, and 10% grown under continuous light at 25 °C for 7 days and 14 days, separately. Characterization of seeds germination pattern, seedlings growth (plant height, fresh and dry weight, and chlorophyll contents), GABA shunt metabolite (GABA, glutamate, and alanine) levels, total protein and carbohydrate levels, and oxidative damage (MDA level) were examined. Data showed a significant effect of drought stress on seed germination, plant growth, GABA shunt metabolites level, total protein and carbohydrate contents, and MDA level. A significant decline in seed germination percentage was recorded at a 20% drought level, which indicated that 20% of soil water holding capacity is the threshold value of water availability for normal germination after 14 days. Seedling fresh weight, dry weight, and plant height were significantly reduced with a positive correlation as water availability was decreased. There was a significant decrease with a positive correlation in Chl a and Chl b contents in response to 7 days and 14 days of drought. GABA shunt metabolites were significantly increased with a negative correlation as water availability decreased. Pea seedlings showed a significant increase in protein content as drought stress was increased. Total carbohydrate levels increased significantly when the amount of water availability decreased. MDA content increased slightly but significantly after 7 days and sharply after 14 days under all water stress levels. The maximum increase in MDA content was observed at 20% and 10% water levels. Overall, the significant increases in GABA, protein and carbohydrate contents were to cope with the physiological impact of drought stress on Pisum sativum L. seedlings by maintaining cellular osmotic adjustment, protecting plants from oxidative stress, balancing carbon and nitrogen (C:N) metabolism, and maintaining cell metabolic homeostasis and cell turgor. The results presented in this study indicated that severe (less than 40% water content of the holding capacity) and long-term drought stress should be avoided during the germination stage to ensure proper seedling growth and metabolism in Pisum sativum L.

Growth response of shallot (Allium ascalonicum L.) seedlings cultured on MS solid and liquid medium supplemented with BAP, Thiamine and Adenine Sulphate

True Shallot Seeds (TSS) is the best choice of cultivation over bulb materials because it offers disease-free plants, produces larger size bulbs, and reduces cost production. In vitro propagation is an alternative method to overcome the TSS development problems. This research aimed to evaluate the growth response of shallot (Allium ascalonicum) cv Tuktuk seedlings, cultured on MS solid and liquid media with agitation supplemented with BAP, Thiamine and Adenine Sulphate. The solid MS medium was used to germinate TSS, followed by growth seedlings at control and treatment media. The experiments were carried out in a Completely Randomized Design with 4 replicates. Data were collected 8 weeks after planting. In vitro germination results showed that 5.96% of seeds started to germinate at the first week and reached 19.82% after four weeks of planting. After 8 weeks in the culture of TSS seedlings, shoots had better growth on solid medium compared to in liquid medium. The addition of BAP, Thiamine and Adenine did not significantly influence the growth of seedlings culture. Bulbs-like bodies were formed in all media. A higher concentration of plant growth regulators might be needed to enhance in vitro propagation of TSS seedlings.

Conservation Activities of Women in Nyangores Forest Station, Mau Conservancy, Kenya

Community-based forest management has increasingly gained popularity in many parts of developing countries. Although the roles of women in forest conservation, management and sustainable utilisation, as well as livelihood improvement, are of paramount importance, it is still scarce and unaddressed in new forest management approaches. Structured questionnaires were administered to 248 Nyangores community forest association members to capture the forest conservation activities of women, determine their role in community forest management and evaluate their socio-economic benefits. Results indicate tree seedling propagation (87.1%), monitoring and evaluation (M&E) (85.1%), and protection of regenerates (84.7%) as the major forest conservation activities. Minor roles included timber harvesting (22.9%), enrichment planting, silvicultural operations (12.9%), and firefighting (8.5%). Accrued socio-economic benefits as a result of women’s role in forest management and conservation were freshwater (95.6%) and firewood (94.8%). These results suggest the incorporation of both genders as a pre-requisite for the success of community forest conservation programs in Mau Conservancy, Kenya.

Diversity assessment and selection of superior Persian walnut (Juglans regia L.) trees of seedling origin from North-Western Himalayan region

North-Western Himalayan region of Jammu and Kashmir has significant Persian walnut (Juglans regia L.) trees, most of which are of seedling origin. The region have rich morphological, phenological, and carpological walnut diversity because of the large variability of native walnut, resulting from cross-pollination and seedling propagation. We studied 84 walnut accessions from this region to assess this diversity and identified trees with superior fruit traits. Studying the growth, leaf, phenological, inflorescence, and fruit characteristics show high variability. Nut weight (NW) ranged from 10.04 to 22.66 g, whereas kernel weight (KW) varied from 4.75 to 14.00 g. In this study, we recorded kernel percentage in a broader range from 30.64% to 61.78%, and shell thickness (ST) from 0.98 to 2.83 mm. The principal component analysis revealed that traits related to KW, kernel percentage, ST, NW, nut length (NL), kernel length (KL), and kernel width (KW) accounted for a large proportion of phenotypic variability. Cluster analysis divided accessions into four cluster groups. We identified three promising genotypes, such as JWSP-06, JWSG-43, and JWSD-59, after considering the important traits in a selection index. These promising genotypes will be used to the benefit of conservation research, cultivation, and breeding. Based on the observed differentiation of variation, it is concluded that the magnitude of phenotypic variation in the population under study is high, and the implication of the results will play a vital role in future walnut breeding programmes.

Effects of Node Position and Electric Conductivity of Nutrient Solution on Adventitious Rooting of Nasturtium (Tropaeolum majus L.) Cuttings

Nasturtium is a popular herbal plant, widely cultivated as culinary and medicinal plants all over the world. However, the seed propagation of nasturtium is inefficient, and in-vitro propagation is sophisticated and high-cost. In this study, the cutting propagation method was employed to produce nasturtium seedlings. We aimed to determine the optimal conditions for cutting propagation of nasturtium seedlings by investigating the effects of node position and electric conductivity (EC) of nutrient solution on the root formation of the cuttings. Cuttings from five node positions (apical bud, 2nd node, 3rd node, 4th node, and 5th node) were subjected to water and five EC (1.0, 2.0, 3.0, 4.0, and 5.0 dS m−1) treatments with a hydroponic cultivation system in a plant factory. Results showed that all cuttings rooted successfully within two weeks. The cuttings from the apical bud position rooted earliest and produced the most roots regardless of EC level. Cuttings from other node positions produced longer roots and heavier root fresh and dry weights than those from the apical bud position. The cuttings under EC of 1.0 dS m−1 had the greatest root number, the longest root length, and the heaviest root fresh and dry weights regardless of node positions. The EC of 1.0 dS m−1 is considered the best condition for nasturtium cuttings for the range of EC tested in this study, and the cuttings from all the five node positions can be used as seedling materials.

Current State and Development of Micro Propagation of Selected High Value Crops in Ethiopia: A Review

Rapid and mass propagation of clean and quality seedlings in horticulture industry becomes a priority for many countries to supply increasing demand of planting materials. Attempt of exploiting the benefit of heterosis from F1 hybrid and overcoming the shortage of planting materials associated with it needs proper intervention. Tissue culture techniques offer disease free, uniform, and large amount of planting materials. The technique is playing a significant role in advancing agriculture in many developing countries in which the current production has to be doubled by 2050. Specially, countries like Ethiopia in which population growth is very high and food insecurity persist, the need for improved production and productivity through the use of modern technologies become apparent. To feed the tremendously growing population, utilization of biotechnology tools such as micro-propagation in agriculture is helpful. Currently, in Ethiopia, somehow there is a fertile ground to exploit the possible advantage which may be acquired from biotechnology as in the case of sugarcane, banana, pineapple etc. micropropagation that boosted the production. This review is therefore to bold out the development of mass-propagation of selected crops and present the current status of protocol optimization of high value horticultural and spice crops. In the meantime, the development of private tissue culture laboratories makes an encouraging advancement where it has to be largely consolidated and highly linked with innovating laboratories to take over the responsibility of multiplying improved varieties. Thus, it can be concluded that despite the development of biotechnology remains at its early stage, promising results were obtained from micro propagation work and if adequate attention given to rapid development of protocol for mass propagation of high value cash crops, there exist untapped potential of biotechnology in Ethiopia.

Exogenous Ethylene Precursors and Hydrogen Peroxide Aid in Early Seed Dormancy Release in Sweet Cherry

Seeds of sweet cherry (Prunus avium) possess a strong endodormancy response that traditionally requires months of stratification before germination can occur. Accelerating artificial dormancy release could be an important aspect of improving progress in a sweet cherry breeding program by increasing the first season growth period. In this study, seeds were exogenously treated with ethephon, 1-aminocyclopropane-1-carboxylic acid (ACC), kinetin, hydrogen peroxide, and acidified nitrite to attempt to induce germination with reduced stratification times. Findings showed that ethephon, ACC, and hydrogen peroxide all significantly increase early seed germination rates. Stratification time had the largest effect on increasing germinations, with significantly higher germination percentages accompanying increased stratification times that plateaued at 3 months of stratification. Stratification is vital for proper seedling development because plants grown from seeds with no stratification are significantly shorter and have reduced internode lengths compared with seeds with 4 weeks of stratification.

Concentrations of indolebutyric acid on air-layering of guava cv. Paluma

Nowadays, the predominant technique for the commercial propagation of guava seedlings is through cuttings, using herbaceous cuttings that need a specialized infrastructure with intermittent misting, clean water, exhausters, water filters, and fans. As an alternative to plant propagation by cuttings, this study aimed to evaluate the influence of concentrations of indolebutyric acid (IBA) on the rooting of branches of the guava cv. Paluma by air-layering. The experimental design was in randomized blocks, with four replications and 10 air layers per plot. The treatments consisted of six concentrations of IBA powder mixed with industrial talcum: 0, 1,000, 2,000, 3,000, 4,000, and 5,000 mg.kg-1. Four adult guava parents that were in the off-season period were used. For the preparation of the air layers, the stems were girdled with a 4.0 cm width, using a steel blade, by removing the bark until exposing the cambium region, followed by IBA application and wrapping of the branches with a plastic bag containing moist organic substrate. The following variables were evaluated 120 days after air-layering: percentage of rooted and callused air layers, longest root length, and root dry matter. The analysis of variance indicated no significant differences between the IBA concentrations for all variables, but the rooting percentages were high (68.6 to 92.2%) regardless of the application of the exogenous auxin.

Genotype-by-environment interaction analysis for grain yield of barley genotypes under dryland conditions and the role of monthly rainfall

In rainfed areas, due to the many variable environmental factors, the introduced cultivars, in addition to high yield, must also have yield stability. In the present study, 15 barley lines along with three local control cultivars under dryland conditions in six cold locations of Iran during three consecutive years (2013–2016) were evaluated. The results showed that the genotype-by-environment interaction is highly significant. The ratios between the sums of squares of G, GE and IPCA1 indicated that the AMMI model is suitable for data analysis. Also, combining AMMI model with BLUP technique and using WAASB index was promising and the results of both were in agreement. With the AMMI1 model, three mega-environments were determined, and the locations of Maragheh, Qamlu and Zanjan were located in the same mega-environment every three years. Finally, it was concluded that the second control cultivar was the most desirable genotype for most environments. Genotypes 16, 15 and 12 with high yield and optimal stability have the ability to be used as new potential genetic resources for improving and stabilizing grain yield in barley breeding programs for cold rainfed conditions. Genotypes 4, 5, and 6 should only be used in narrow adaptation to restricted environments. On the other hand, rainfall in November and January is important for proper seedling establishment, and rainfall in April and May is important for pollination and grain filling period.

USE OF RITA® TEMPORARY IMMERSION SYSTEM TO OBTAIN MICROTUBERS OF SEVERAL MASHUA (Tropaeolum tuberosum Ruiz & Pavón) MORPHOTYPES

<p><strong>Background. </strong>The Temporary Immersion System (TIS) is an effective strategy to obtain quality mashua microtubers through the <em>in vitro</em> propagation of seedlings in a small space and in a short period of time. <strong>Objective. </strong>Obtain microtubers of 27 mashua morphotypes (<em>Tropaeolum tuberosum</em>)<em> </em>using the TIS-RITA<sup>®</sup>. <strong>Methodology.</strong> The seedlings were previously propagated in MS (Murashige & Skoog) solid medium, supplemented with 3% sucrose, at 5.6 pH and 0.7% agar. After fifteen days of cultivation in this medium, the seedlings were transferred to a MS liquid. For the tuberization process, seedlings with an average size of 10 cm were transferred to TIS-RITA® systems for ten weeks, under conditions of complete darkness, at 19 ± 2 ° C, an immersion frequency of 2 minutes every 3 hours in a MS liquid medium supplemented with 8% sucrose and 2 mg.L<sup>-1</sup> benzylamino purine (BAP). <strong>Results. </strong>The best results of microtubers were obtained with different morphotypes, which are respect to i/size, MAC 06A (1.9 cm) and MAC 056 (1.8 cm); ii / fresh weight, MAC 06A (0.2g) and MAC 092 (0.18 g); iii / quantity, MAC 08A (51 units) and MAC 048 (56 units). <strong>Implications</strong>. TIS-RITA<sup>®</sup> can be used to obtain quality and virus-free seeds of a wide variety of commercially important crops. <strong>Conclusion</strong>. The SIT-RITA® based on the intermittent contact of the explants cultivating medium, is an efficient system to obtain mashua microtubers.</p>

Study on Artificial Seeds of Plants

The establishment and development of artificial seed technology is to quickly reproduce excellent varieties or hybrids, which can be applied to hybrid generation seeds produced by the three-two line method. For some varieties that are difficult to propagate with seeds or plant species with unstable genetic traits and poor fertility, artificial seed technology can also be used for mass reproduction. In particular, some new plants created through genetic engineering, such as somatic hybrids or transgenic plants, can be propagated or maintained by artificial seed technology. In addition, artificial seed technology can be used for the maintenance and rapid propagation of virus-free seedlings. Compared with ordinary test tube seedlings, artificial seeds have low cost, convenient transportation, and to a certain extent reduce vitrified seedlings.In particular, the production of artificial seeds does not occupy a large amount of soil. It can be produced all year round. Therefore, the research on artificial seeds has developed rapidly in the world.

Formula Fertilization Promotes Phoebe bournei Robust Seedling Cultivation

Phoebe bournei is a rare and endangered woody species and the success of its plantation development is dependent upon proper seedling cultivation. This study explored the regulation of N, P and K fertilizer and the interaction of these macronutrients on the growth of Phoebe bournei seedlings. To determine the optimum rate and ratio of N–P–K fertilizer in seedling cultivation, we used the unique “3414” incomplete orthogonal regression design to evaluate the effects of N–P–K fertilization on seedling morphological development. One-year-old Phoebe bournei bareroot seedlings were grown for one growing season under the defined fertilization regime, with their morphological development determined by measuring seedling attributes—root, stem, leaves and total biomass, root collar diameter and seedling height. These attributes were then combined to calculate the following indices: height-diameter ratio, shoot-root ratio and the seedling quality index (QI). Results showed that the N–P–K fertilizer had significant and beneficial effect on seedling cultivation. N effect was highest, followed by K and P. The three-way N×P×K interaction effect was strong, and the two-way interactions effect was highest for N×P, followed by P×K and N×K. At the “2” level of N (0.532 g·plant−1), P (P2O5, 0.133 g·plant−1), and K fertilizer (K2O, 0.356 g·plant−1), seedling growth and biomass accumulation were at their maximum. Unary, binary, and ternary quadratic fertilizer effect function equations of QI were established. Through comparative analysis, the ternary quadratic model was the optimal model and through a simulation–optimization, the optimal N–P–K fertilizer rates were 0.373~0.420 g·plant−1 (N), 0.086~0.106 g·plant−1 (P2O5), 0.243~0.280 g·plant−1 (K2O), with a N–P–K ratio of 1:0.20:0.43~1:0.65:0.75.

Efficacy of substrate and humic substance on cuttings production of Spondia purpurea L.

For the propagation of seedlings by cutting it is important to select an appropriate substrate. Additionally, the use of humic substances can stimulate the growth of the plants, as is already known for many species. We aimed to investigate the influence of substrates based on carnauba bagana and carbonized rice husk associated with humic substance - HS in the production of Spondia purpurea L. seedlings by cuttings. We studied three proportions (v:v) of substrates, namely, 100% carbonized rice husk; 50% carnauba bagana + 50% carbonized rice husk; 100% carbonized rice husk and four doses of the humic substance, namely, 0 g L-1; 12.5 g L-1; 25 g L-1; 50 g L-1. The experiment was arranged in a completely randomized design, in a 3x4 factorial with four replicates. There was a significant effect of HS doses and substrate interaction and HS doses on the leaf area and dry mass of the aerial part of seedling seedlings. Root volume was affected in isolation by the factors tested. The interaction responses between the substrate and doses of humic substance infer that they act in different ways on development of seriguela seedlings according to the type of substrate, therefore, it is essential to identify and choose the compiled that favors the best results. There is then a need test other substrates associated with the addition of HS, already known to condition the increase of seriguela seedlings produced by cuttings.