Acclimation Of Seedlings Research Articles

Control of Meloidogyne javanica in banana by endophytic bacteria

Abstract The aim of this work was to evaluate the effect of 40 endophytic bacteria isolates on the control of Meloidogyne javanica in ‘Prata-Anã’ banana seedlings. Two experiments were carried out in a completely randomized design with eight replicates. In each trial, 20 bacteria isolates and control were evaluated. Bacterial suspensions were applied to substrates during the acclimatization of seedlings at 15 and 30 days. On the 31st day, seedlings were transplanted into pots and soil was infested with M. javanica egg suspension at 8 days. After 90 days, the following variables were evaluated: number of galls, egg masses, eggs per root, reproduction factor (RF), second-stage juveniles, and shoot dry matter. The results of nematological variables were submitted to Principal Components Analysis. In trial I, the variables that most contributed to data variability were as follows: number of eggs and RF. In trial II, RF had greater influence. Of the 40 isolates evaluated, 39 reduced RF, and of the 20 isolates evaluated in the first trial, all reduced the number of eggs per root. Bacillus methylotrophicus EB26, Bacillus cereus EB25, and Bacillus sp. EB37 isolates stood out in the control of nematodes, with RF reduction above 80%.

In vitro regeneration of Senna alata (L.) Robx. (Fabaceae): An ancient medicinal plant

Senna alata, a legume of medicinal importance, presents antifungal and antibacterial antioxidant activity. The main limitation is the presence of seeds with integument dormancy within natural populations. This study aimed to establish an efficient protocol for the in vitro propagation and acclimatization of seedlings. The seeds were disinfected with different concentrations of NaOCl; for the regeneration of the shoots, cotyledon segments were inoculated in MS and WPM medium, supplemented with plant growth regulators, auxins (1-NAA and 2,4-D), interaction with cytokinins (TDZ and BAP), and activated carbon. The seedlings were acclimated in nursery conditions using vermiculite, sand, and soil substrates. Using NaOCl (0.5%) for 30 min resulted in 98.0% disinfected seeds while 95.4% of scarified seeds germinated. High node and shoots numbers (8.3 ± 0.4; 12.6 ± 0.8, respectively) were obtained when using the MS medium containing 1-NAA + TDZ (0.1 + 1.0 mg L-1), while the use of MS medium supplemented with 2,4-D + TDZ (0.1 + 1.0 mg L-1) resulted in longer shoots (6.0 ± 0.5 cm). Using WPM medium with IBA + BAP (1.0 + 0.1 mg L-1) improved rooting (14.0 cm ± 1.3) and the number of roots (5.0 ± 0.0) in the treated plants. The vermiculite substrate with sand promoted 81.5% of acclimatized plants. This study allowed obtaining high levels of germination, regeneration in vitro and acclimatization of S. alata.

Conservation Horticulture: In Vitro Micropropagation and Acclimatization of Selected Florida Native Orchids

Florida is home to 106 native orchid species, of which 77 are listed as endangered or threatened by the State of Florida. The Institute for Regional Conservation (IRC) has classified 62 of these species as either critically imperiled, imperiled, or rare in South Florida. Because of lack of endosperm, orchid germination rates are very low in nature, as they depend on an obligate relationship with mycorrhizal fungi for nutrients. Most orchid seeds can be germinated in vitro without the need for specific mycorrhizal fungi. This study aims are to establish a fast and efficient protocol for in vitro seed germination using different nutrient media and plant growth regulator (PGR) combinations, and to optimize seedling acclimatization protocols using different greenhouse media. To determine germination preferences, three different in vitro seed germination media were tested supplemented with PGRs, including 1) Murashige & Skoog (MS) (control), 2) MS supplemented with 1.5 mg/L 6-benzylaminopurine (BAP), and 3) MS supplemented with 1 mg/L BAP and 0.5 mg/L 1-Naphthaleneacetic acid (NAA) on Cyrtopodium punctatum, a state-listed endangered, IRC critically imperiled epiphytic orchid. There was no significant difference amongst the treatments after 2 and 6 weeks of seed sowing culture. To understand post-culture survivorship, two epiphytic and one terrestrial native species (Trichocentrum undulatum, Encyclia tampensis, and Oncidium ensatum) were chosen for the acclimatization study with two commercially available potting substrates (coir, sphagnum). To measure seedling growth rates, phenotypic measurements [leaf number, leaf length, root length, plantlet height, light intensity, pH, and electrical conductivity (EC)] and Soil Plant Analysis Development (SPAD) and Normalized Difference Vegetation Index (NDVI) values were recorded monthly for five months. All media/PGR combinations resulted in an initial high percentage of stage I growth but inhibited Protocorm-like bodies (PLBs) development, suggesting more research is necessary to determine later improvements or detriments to MS basal media with BAP and NAA. Comparing acclimatization media with the three species of orchid chosen for this experiment, neither O. ensatum nor E. tampensis showed a marked preference for sphagnum moss or coir. However, T. undulatum did perform better with coir compared with sphagnum. This research will help botanical gardens and commercial plant tissue culture laboratories to have a better understanding on selection of PGR combinations for in vitro cell culture and acclimatization media on increasing the viability and plant health and decreasing the mortality of endangered plants.

Association of growth-promoting bacteria and hydroponic system aiming at reducing the time of production of banana seedlings

ABSTRACT Banana micropropagation allows the production of vigorous and high-quality phytosanitary plants, which can be improved with the use of endophytic growth-promoting bacteria (PGPB) that stimulate the growth and development of plants. It is possible to associate them with hydroponics, allowing a high supply of seedlings and reducing the production cycle. The objective was to evaluate the effect of PGPB in a floating hydroponic system in the acclimatization phase of banana. The cultivars studied were Prata Anã and BRS Princesa. The treatments evaluated were as follows: control (nutrient broth without bacteria); Bacillus cereus strain 1 (BC1); Bacillus cereus strain 2 (BC2); Bacillus thuringiensis (BT); Buttiauxella agrestis (BA). Total height, pseudostem diameter, root length, number of leaves, fresh root mass, pseudostem, leaf and leaf area, stomatal conductance, internal carbon concentration, photosynthesis rate, transpiration rate, leaf temperature and chlorophyll. Bacteria B. cereus strain 2 and B. agrestis in the cultivar Prata Anã and B. agrestis in BRS Princesa improved the acclimatization process of the seedlings in a floating hydroponic system. Stimulating plant growth, fresh weight and promoting root growth. The association of bacteria and hydroponics allowed the reduction of the seedling acclimatization period from 90 to 25 (Prata Anã) and 15 days (BRS Princesa).

Abundance and diversity of arbuscular mycorrhizal gungal (AMF) spores isolated from the rhizosphere of papaya and other different cropping systems in Central Kenya

Arbuscular mycorrhiza fungi (AMF), obligate symbionts, are important in the majority of cultivated plant species in colonizing roots and supporting plant growth in adverse climatic conditions. However, the abundance and quality of mycorrhizal colonization is affected by land-use types, cropping systems and climate change. On the other hand, rhizospheric mycorrhizae present in rhizospheric soils can be isolated for enhancing plant performance. One such opportunity arises in the acclimatization of seedlings for adaptation to depleted field conditions. Isolation and characterization of rhizospheric AMF species is important in evaluating the efficiency of colonization especially in plants that have not been previously evaluated such as papaya, which is well known for its high nutritive value. In this study, soils were sampled from grass, banana and papaya plants’rhizosphere, from three different papaya growing regions in Kenya; Mwea, Mitunguu and Juja. Spores were isolated using the sucrose method. Spore abundance was done using a gridded Petri dish and morphologically characterized using the International Culture Collection of Vesicular Arbuscular Mycorrhizal Fungi (INVAM) database. At least 4 families, 10 genera and 41 species of glomeromycota phylum were isolated from the 3 sampling sites. The families of glomeraceae (16 species) and acaulosporaceae (14 species) dominated in Juja and Mwea Sub Counties. Glomus spp. isolated from the rhizosphere of banana and grass plants were the most abundant, at p≤0.05, in Juja while Diversispora spp (diversisporaceae) was the least abundant, at p≤0.05. Mwea Sub County had the most spore abundance, at p≤0.05, compared to Mitunguu and Juja. Mycorrhizal spores isolated from the grass family were the most abundant, at p≤0.05, (Mwea, 41; Juja, 37; Mitunguu, 35.2) as opposed to banana and papaya plants. The results showed that AMF spore abundance and diversity varies with different locations and the associating plants.

In vitro germination of Abricó-de-Macaco (Couroupita guianensis aubl.)zygotic embryos in different culture media and light spectra

ABSTRACT: Couroupita guianensis Aubl. is an Amazonian forest species with important medicinal and ornamental value. This study evaluated the effect of different culture media and light spectra on the in vitro germination and development of the zygotic embryos of C. guianensis. The culture media, MS and WPM, were evaluated without the addition of plant growth regulators and were associated with four LED light spectra: white (CW), 70% red + 30% blue (R2B), 100% red (R), and 100% blue (B). One hundred percent of the seeds successfully underwent in vitro germination, and the culture media did not interfere with embryo development. In addition to this, the different light spectra induced in vitro morphogenesis and R2B treatment significantly promoted the production of secondary roots. This effect may aid in the rooting and acclimatization of seedlings of this species.

Influence of the photosynthetic photon flux density value on microclimate in healing and acclimatization tunnels for vegetable seedlings

For seedlings production, healing and acclimatization are the most important processes in obtaining healthy and vigorous plants. Influence of photosynthetic photon flux density (PPFD) on a healing tunnel environmental parameters was investigated. The experiments were carried out at HORTING institute’s micro-production greenhouse using 9 alveolar trays with 104 eggplant seedlings each, placed in two sections of the specialized tunnels for healing and acclimatization of seedlings. In each section and in the research greenhouse was measured the levels of photosynthetic photon flux density, of temperature, of the relative humidity and the level of CO2 concentration. From the meteorological station of the HORTING institute, data on the variation of outdoor temperature, relative humidity and light intensity were downloaded. The variation of the micro-climate factors in the two sections according to their external environmental conditions were compared. One of the conclusions is that seedlings that have benefited from an additional artificial source of light have a more intense photosynthetic activity. The difference on CO2 concentration in the two sections over the same time period lead to this conclusion. This gives the certainty of obtaining healthy and vigorous plants in the sections with supplementary lighting.

A method for experimental warming of developing tree seeds with a common garden demonstration of seedling responses

BackgroundForest dieback driven by rapid climate warming threatens ecosystems worldwide. The health of forested ecosystems depends on how tree species respond to warming during all life history stages. While it is known that seed development is temperature-sensitive, little is known about possible effects of climate warming on seed development and subsequent seedling performance. Exposure of seeds to high air temperatures may influence subsequent seedling performance negatively, though conversely, warming during seed development may aid acclimation of seedlings to subsequent thermal stress. Technical challenges associated with in-situ warming of developing tree seeds limit understanding of how tree species may respond to seed development in a warmer climate.ResultsWe developed and validated a simple method for passively warming seeds as they develop in tree canopies to enable controlled study of climate warming on seedling performance. We quantified thermal effects of the cone-warming method across individual pine trees and stands by measuring the air temperature surrounding seed cones using thermal loggers and the temperature of seed cone tissue using thermocouples. We then investigated seedling phenotypes in relation to the warming method through a common garden study. We assessed seedling morphology, physiology, and mycorrhizal nodulation in response to experimental cone-warming in 20 seed-source-tree canopies on the San Francisco Peaks in northern Arizona, USA. The warming method increased air temperature surrounding developing seed cones by 2.1 °C, a plausible increase in mean air temperature by 2050 under current climate projections. Notable effect sizes of cone-warming were detected for seedling root length, shoot length, and diameter at root collar using Cohen’s Local f2. Root length was affected most by cone-warming, but effect sizes of cone-warming on root length and diameter at root collar became negligible after the first year of growth. Cone-warming had small but significant effects on mycorrhizal fungal richness and seedling multispectral near-infrared indices indicative of plant health.ConclusionsThe method was shown to reliably elevate the temperature surrounding seed cones and thereby facilitate experimental in-situ climate warming research on forest trees. The method was furthermore shown to influence plant traits that may affect seedling performance under climate warming.

Effect of hydric and light stress on biomass, nutrient uptake and enzymatic antioxidants of Argania spinosa seedlings

Sunlight and water are factors that affect seedling development. However, the effects of acclimatization of seedlings to sunlight and water stress remain poorly understood. This study aimed to examine the interactive effects of acclimatization to light and water stress on argan tree (Argania spinosa) seedlings in nurseries. An experiment was conducted with 504 seedlings using two sunlight treatments (L1 and L2, i.e. 100% and 60% of full sunlight, respectively), and three watering treatments (well-watered, moderate stress and severe stress, i.e. 100%, 50% and 25% of field capacity, respectively). According to our results, water stress treatments caused a reduction in total biomass accumulation, nitrogen and phosphorus uptake. Water stress significantly increased other macroelements, H2O2 and MDA levels and antioxidant enzyme activities compared to well-watered seedlings. Seedlings grown under moderate shade (L2) showed higher macroelement uptake, which probably contributed to the increase in total biomass in all water treatments. The highest membrane stability index (MSI) values, H2O2 and MDA levels and lowest antioxidant enzyme activities were recorded in acclimatized argan seedlings under moderate shading (L2). These results suggest that moderate shade can effectively prevent stress caused by light excess and can also mitigate the harmful effects of water stress on A. spinosa seedlings.

Breeding of a Medium-Sized and fragrant <i>Cymbidium</i> ‘Aroma Pink’

We report a new hybrid Cymbidium, ‘Aroma Pink,’ bred at the National Institute of Horticultural and Herbal Science, Rural Development Administration, in 2017. The hybrid was derived from the cross of C. Lucky Rainbow ‘Lapin Hot’ and C. eburneum in 2000. After the artificial crossing, 120 seedlings were obtained through in vitro seed germination and seedling acclimatization in a greenhouse. Based on a number of characteristics, including flower color, leaf shape, flower stalk, and vigorous growth, three initial lines were selected. The first and second trials for characteristics were conducted from 2011 to 2016, confirming the stability and uniformity of the three lines, and one final line, coded ‘00-1174-100’, was selected as ‘Wongyuo F1-62’ and named ‘Aroma Pink.’ This hybrid is a medium-sized plant with white petals (WNN155D), light pink colored sepals (RP62D), and yellow lip (Y2B). The flower has an incurved shape and the dimensions are 6.1 cm (length) and 5.2 cm (width), making it a relatively compact flower. Overall, its shape and size resemble that of its female parent, but instead of a dark red lip, it has a yellow lip that is similar to the male parent, giving a bright overlook rather than an intense impression. Each plant has 2.9 stalks on average and 6.5 flowers attached on each stalk. Although the number of flowers is relatively less, the flower has a delicate fragrance that is similar to that of C. eburneum. In addition, the new hybrid has a stable shape with erect peduncle and less drooping leaves. ‘Aroma Pink’ begins to bloom from March, under normal cultivation and without the need of moving it to a high altitude area. Although the color of the flower can become blurred in high temperature during flowering season, this hybrid is easy to cultivate and manage.

An Assessment of Storability of Norway Spruce Container Seedlings in Freezer Storage as Affected by Short-Day Treatment

Determination of safe times at which to transfer seedlings to freezer storage is problematic in forest tree nurseries. The present study aimed to determine the relationship between pre-storage frost hardiness (FH) of different plant parts, dry matter content (DMC), chilling hours (the sum of hours when temperature was between −5 °C and +5 °C), and post-storage vitality, and the impact of short-day (SD) treatment on these relationships. One and a half year old control seedlings and SD-treated seedlings of Norway spruce were transferred to freezer storage (−3 °C) on five occasions during autumn. On each occasion, the FH of buds, needles, stem, and roots, as well as DMC, were determined, and chilling hours were calculated. The vitality of the freezer-stored seedlings was determined through their root growth capacity in the subsequent spring, and through the field performance of the seedlings (shoot growth and seedling damage) at the end of the following two growing seasons. Seedlings were considered to be storable when the FH of the needles was at least −25 °C, and the FH of the roots was about −10 °C in both treatments. Early storage reduced the vitality of the seedlings. SD treatment did not advance the storability of the seedlings, although it alleviated some of the negative effects of early storage by improving the FH of needles and stem, but not that of the roots. The DMC value, indicating storability, was higher for SD-treated seedlings than for control seedlings. When data from five experiments conducted in Suonenjoki were combined, it was found that the relationship between accumulation of chilling hours and needle FH was dependent on nursery treatment and assessment year, which reduces the reliability of using chilling hours in predicting the storability of Norway spruce seedlings. The predicted climate change may complicate the fall acclimation of seedlings. New, user-friendly methods for determining storability of seedlings are urgently needed.

Effect of acclimation environments, grafting methods and rootstock RVTC-66 on the seedling development and production of tomato

Grafting is a common practice used in tomato to control soil pathogen problems, confer tolerance against abiotic stresses and, when possible, increase yield. The objective of this study was to evaluate the grafting development and interaction of a commercial tomato cultivar (cv. Giuliana) grafted onto the S. lycopersicum var. cerasiforme genotype RVTC-66, and self-grafted, with four acclimation environments after grafting (three plant growth chambers with 23/18, 25/20 and 28/23 °C in day/night; and a healing chamber with mean temperature of 23.2 °C ± 0.28), and using the cleft and approach grafting methods. Additionally, the effect of the RVTC-66 rootstock using both grafting methods on the photosynthetic efficiency and production of Giuliana cultivar grafted was also evaluated. Survival of grafted plants, plant height, number of leaves, foliar area, stem dry matter and leaf dry matter had significant interaction between acclimation environment and grafting methods. The plant growth chamber (25/20 °C) and healing chamber (mean 23.2 °C) favored the healing of the grafted (with survival of grafted of > 97.50%) and seedling development. Approach grafting method was favorable only to the plant growth chamber with temperatures of 25/20 and 28/23 °C (day/night). The cleft grafting method combined with the acclimation of seedlings in healing chamber (mean 23.2 °C) improved survival and development of seedling shoots. Grafting methods had no influence in photosynthetic efficiency and production of Giuliana tomato cultivar grafted onto RVTC-66. In contrast, the RVTC-66 rootstock provided an increase in seedling root development, photosynthetic efficiency and fruit production of grafted tomato plants.

Brassinosteroid accelerates the growth of Psidium hybrid during acclimatization of seedlings obtained from minicuttings

ABSTRACT Guava rootstocks can be multiplied by minicuttings in environment with a high relative humidity, being necessary an acclimatization period. Certain growth regulators favor the acclimatization, with brassinosteroids being successfully used in other fruit plants. This study aimed to shorten the multiplication time of the BRS Guaraçá hybrid by applying Biobras-16 (BB-16) during the acclimatization of seedlings obtained from minicuttings. The treatments consisted of five BB-16 concentrations (0, 0.1, 0.3, 0.5 and 1.0 mg L-1), applied in a randomized block design, in a split-plot arrangement, with four replications and five seedlings per plot, repeated at two seasons: winter and spring/summer. After 60 days of acclimatization, shoot and root growth indicators increased as a function of the BB-16 application, particularly at concentrations between 0.3 and 0.6 mg L-1. The brassinosteroid can be used to stimulate the growth of BRS Guaraçá seedlings obtained from minicuttings, shortening its production time and improving its seedling quality.

Roles of arbuscular mycorrhizal fungi on acclimatization of clones of Coffea arabica L. produced by somatic embryogenesis

ABSTRACT The production of Coffea arabica L. clone seedlings through the somatic embryogenesis technique is one of the alternatives of greatest demand for coffee producers. However, clones can face difficulties related to acclimatization carried out under greenhouse conditions, which can increase the production costs. A tested alternative with promising results is inoculation with arbuscular mycorrhizal fungi (AMF) during the seedling acclimatization process. Thus, this study aimed to promote the improvement of the seedling production process through somatic embryogenesis associated with inoculation with AMF. For the production of the clones, seedlings were used in the phase when they presented four pairs of leaves (Clone 1 “Fruiting red Catucaí” and Clone 2 “Acauã”), using “somatic embryogenesis” bioreactors, followed by inoculation with Rhizophagus clarus, Gigaspora margarita and Acaulospora mellea, a mixture of R. clarus and G. margarita and a mixture of R. clarus, G. margarita and A. mellea. After six months, agronomic parameters, leaf nutrient contents and root mycorrhizal colonization were evaluated. The studied clones behaved differently when inoculated with AMFs. Clone 1 showed the best development in the greenhouse, which was determined by the agronomic parameters. Thus, Clone 1 is indicated for the production of vigorous seedlings when associated with inoculation with AMFs.

Acclimatization of micropropagated seedlings of pineapple cultivars on organic substrates

Fusariosis constitutes an important hindrance to pineapple farming in Brazil. The cultivars resistant to fusariosis, ‘Vitoria’ and ‘Imperial’, from in vitro culture, are an alternative for crop management. This work evaluates the veg­etative performance of pineapple cultivars propagated by tissue culture in response to the use of organic sub­strates, different in nature and proportion. The experimental design was a completely randomized block, arranged in a 3×5 factorial scheme, with three pineapple cultivars (‘Perola’, ‘Vitoria’, and ‘Imperial’) and five substrates [ORG: Organoamazon®, organic compound; SS: Standard Substrate, soil + sand (1:1 v/v); SS + M + C: SS + sheep manure (M) + carbonized rice husk (C) (2:1:1 v/v); SS + M (3:1 v/v); SS + C (3:1 v/v), unfolded in mean contrasts]. The variables analyzed were shoot and root growth and shoot nutrient content. The vegetative perfor­mance of cultivars, considering the increase of shoot dry weight in the most responsive substrate, was: ‘Perola’ > ‘Vitoria’ > ‘Imperial’. Substrate ORG promoted higher increases in shoot dry weight (259%) and root density (116%) compared to the average of the other substrates. The growth promoted by ORG resulted in higher N, P, K, Ca, and Mg content in pineapple plants. Substrates ORG and SS + M + C are recommended for acclimatiza­tion of in vitro propagated pineapple seedlings in the period of ex vitro seedling acclimatization.

Ex vitro acclimatization of Hippeastrum reticulatum (Amaryllidaceae) using different substrates

ABSTRACT: Hippeastrum spp. are herbaceous species belonging to the family Amaryllidaceae, widely marketed worldwide as indoor plants. Aiming to characterize chemically and physically and to compare five substrates in acclimatization, micropropagated seedlings of Hippeastrum reticulatum var. striatifolium (Herb), with an average of four roots, two leaves and bulbs with a 4.7mm diameter, were transplanted to 50-cell polyethylene trays each containing the following substrates: T1 - vermiculite, T2 - carbonized rice husk (CRH), T3 - commercial (peat + vermiculite + CRH), T4 - coconut fiber, and T5 - composted Pinus bark. After transplantation, the trays were kept for 17 days at a greenhouse with intermittent irrigation by nebulization, and 80 days at a greenhouse on a bench with intermittent irrigation by capillarity. The experimental design was randomized blocks with seven replications and ten seedlings per plot. The acclimatization of seedlings was efficient for the substrates tested despite the differences verified by chemical and physical characterization. The mean survival rate was 96%. However, seedlings acclimatized in the T5 substrate showed a qualitative improvement due to a higher formation of roots, leaves and fresh matter.

SELECTION OF Coffea arabica L. HYBRIDS USING MIXED MODELS WITH DIFFERENT STRUCTURES OF VARIANCE-COVARIANCE MATRICES

This study aimed to evaluate different structures of variance-covariance matrices in modeling of productive performance of coffee genotypes over the years, and select hybrids of <em>Coffea arabica</em> using mixed models. A mixed linear model was used to estimate variance components, heritability coefficients, and prediction of genetic values of hybrids and cultivars. Three commercial cultivars and eight hybrids of <em>C. arabica</em> L. were evaluated. The field production after acclimatization of seedlings was conducted in March 2006. The yield averages from 2009, 2010, 2011, 2013, and 2014 agricultural years were evaluated. The selection criteria of models were used to test 10 structures of variance-covariance matrices, and later a model was chosen to estimate the components of variance, heritability coefficients, and prediction of genetic values. According to Bayesian information criterion (BIC), the best structure was ARMA (Autoregressive Moving Average); however, considering the Akaike Information Criterion (AIC) and corrected Akaike Information Criterion (AICC), the CSH (Heterogeneous Composite Symmetric) was indicated. The Spearman correlation between the genotypic values obtained in the models with ARMA and CSH type R matrix was 0.84. The high and positive correlation indicates that the best model could involve the R matrix with ARMA or CSH structure. The heritability of individual genotypes differed from heritability in broad sense, which considers the independence among agricultural years. Hybrids with higher performance were identified by ordering the genotypic effects, among them, H 2.2, H 4.2, and H 6.1 hybrids were highlighted.

In vitro propagation and seedling acclimatization of Caesalpinia ferrea Mart., a valuable medicinal plant in the Amazon (Fabaceae)

The objective of this work was to establish a protocol for the rapid in vitro multiplication of Caesalpinia ferrea Mart., aimed at genetic selection and in vitro germplasm conservation. Seeds treated in different sodium hypochlorite solution concentrations were inoculated in Murashige and Skoog (MS) culture medium and maintained in a growth room. After 30 days, sodium hypochlorite at 0.25% concentration resulted in 96.67% survival and 90% germination of the seeds. In the explants multiplication phase three types of medium culture were evaluated supplemented with cytokinins and auxins in different concentrations and combinations. The addiction of 0.1 mg·L-1 Benzylaminopurine (BAP) and 0.1 mg·L-1 Indole butyric acid (IBA) induced 100% of explants with shoots and 32% with root formation, while a complete absence of callus was found. It was observed that 90% of explants derived from the buds developed shoots with 2.73 cm and greater multiplication rate (10.06). The seedlings obtained from in vitro multiplication were acclimated without the presence of roots in different types of substrate. After 60 days, soil substrate was most indicated for acclimatization, showing 63.33% of healthy and uniform plants. In vitro propagation of C. ferrea allows the establishment and multiplication of in vitro seedlings from nodal segments and axillary buds.

Leaf non-structural carbohydrate allocation and C:N:P stoichiometry in response to light acclimation in seedlings of two subtropical shade-tolerant tree species

Light availability greatly affects plant growth and development. In shaded environments, plants must respond to reduced light intensity to ensure a regular rate of photosynthesis to maintain the dynamic balance of nutrients, such as leaf non-structural carbohydrates (NSCs), carbon (C), nitrogen (N) and phosphorus (P). To improve our understanding of the nutrient utilization strategies of understory shade-tolerant plants, we compared the variations in leaf NSCs, C, N and P in response to heterogeneous controlled light conditions between two subtropical evergreen broadleaf shade-tolerant species, Elaeocarpus sylvestris (E. sylvestris) and Illicium henryi (I. henryi). Light intensity treatments were applied at five levels (100%, 52%, 33%, 15% and 6% full sunlight) for 30 weeks to identify the effects of reduced light intensity on leaf NSC allocation patterns and leaf C:N:P stoichiometry characteristics. We found that leaf soluble sugar, starch and NSC concentrations in E. sylvestris showed decreasing trends with reduced light intensity, whereas I. henryi presented slightly increasing trends from 100% to 15% full sunlight and then significant decreases at extremely low light intensity (6% full sunlight). The soluble sugar/starch ratio of E. sylvestris decreased with decreasing light intensity, whereas that of I. henryi remained stable. Moreover, both species exhibited increasing trends in leaf N and P concentrations but limited leaf N:P and C:P ratio fluctuations with decreasing light intensity, revealing their adaptive strategies for poor light environments and their growth strategies under ideal light environments. There were highly significant correlations between leaf NSC variables and C:N:P stoichiometric variables in both species, revealing a trade-off in photosynthesis production between leaf NSC and carbon allocation. Thus, shade-tolerant plants readjusted their allocation of leaf NSCs, C, N and P in response to light acclimation. Redundancy analysis showed that leaf morphological features of both E. sylvestris and I. henryi affected their corresponding leaf nutrient traits. These results improve our understanding of the dynamic balance between leaf NSCs and leaf C, N and P components in the nutritional metabolism of shade-tolerant plants. Key messageTwo species of understory shade-tolerant plants responded differently to varying light intensities in terms of leaf non-structural carbohydrate allocation and the utilization of carbon, nitrogen and phosphorus to balance nutritional metabolism and adapt to environmental stress.

THE GROWTH PERFORMANCE OFMICROPROPAGATED TALASBANANA (Musa paradisiaca var. sapientum L) SEEDLINGS CULTIVATED ON PEATLANDS

<p align="center"><strong>ABSTRACT</strong></p><p>Talas banana (<em>Musa paradisiaca</em> var. <em>sapientum</em> L.) has a high economic value. However, because of slowly breeding, a quick way of propagation: i.e. in vitro is required.Peatlands inSouth Kalimantan are quite large and has potential to be used for planting area of Talas banana. The acclimatization of seedlings planted on the peatsrequires more fertilizers, considering the low nutrient content of the peats. This study aims to determine the chicken manure and nitrogen-phosphor-potassium (NPK) fertilizer on the growth of Talasbanana acclimatized in peatlands. This study applied a randomized block design (RBD) factorial: (1) the amount of chicken manure (K), namely: k<sub>1</sub> = 5 t ha<sup>-1</sup>; k<sub>2</sub> = 10 t ha<sup>-1</sup>; k<sub>3</sub> = 15 t ha<sup>-1</sup>; k<sub>4</sub> = 20 t ha<sup>-1</sup>, and (2) the amount of NPK fertilizers (P), namely: p<sub>1</sub> = 200 kg ha<sup>-1</sup>; p<sub>2</sub> = 250 kg ha<sup>-1</sup>; p<sub>3</sub> = 300 kg ha<sup>-1</sup>. Therefore, 12 treatments. DITAMBAHKAN TERDAPAT 12 PERLAKUAN. All treatments have 3 replicates. The results of the experiment showed that there was no interaction between doses of chicken manure with NPK. The amount of chicken manure 5 t ha<sup>-1</sup> resulted in the highest increment of plant height observed at 2<sup>nd</sup>, 4<sup>th</sup>, 6<sup>th</sup>, 8<sup>th</sup>, 10<sup>th</sup> and 12<sup>th</sup>week after planting, increment of stem diameter, addition of leaf number, width and length of leaves.The results of experiment also revealed that the best increment of plant height observed at 8<sup>th</sup> week after planting and stem diameter observed at 4<sup>th</sup> week after planting was obtained by 250 kg ha<sup>-1</sup>of NPK fertilizer application. KOMBINASI TIDAK BERPENGARUH</p>Key-word: propagation; in vitro; peatlands; chicken manure; Talas banana