Male Inflorescences Research Articles

Characterization of Phytohormones and Transcriptomic Profiling of the Female and Male Inflorescence Development in Manchurian Walnut (Juglans mandshurica Maxim.).

Flowers are imperative reproductive organs and play a key role in the propagation of offspring, along with the generation of several metabolic products in flowering plants. In Juglans mandshurica, the number and development of flowers directly affect the fruit yield and subsequently its commercial value. However, owing to the lack of genetic information, there are few studies on the reproductive biology of Juglans mandshurica, and the molecular regulatory mechanisms underlying the development of female and male inflorescence remain unclear. In this study, phytohormones and transcriptomic sequencing analyses at the three stages of female and male inflorescence growth were performed to understand the regulatory functions underlying flower development. Gibberellin is the most dominant phytohormone that regulates flower development. In total, 14,579 and 7188 differentially expressed genes were identified after analyzing the development of male and female flowers, respectively, wherein, 3241 were commonly expressed. Enrichment analysis for significantly enriched pathways suggested the roles of MAPK signaling, phytohormone signal transduction, and sugar metabolism. Genes involved in floral organ transition and flowering were obtained and analyzed; these mainly belonged to the M-type MADS-box gene family. Three flowering-related genes (SOC1/AGL20, ANT, and SVP) strongly interacted with transcription factors in the co-expression network. Two key CO genes (CO3 and CO1) were identified in the photoperiod pathway. We also identified two GA20xs genes, one SVP gene, and five AGL genes (AGL8, AGL9, AGL15, AGL19, and AGL42) that contributed to flower development. The findings are expected to provide a genetic basis for the studies on the regulatory networks and reproductive biology in inflorescence development for J. mandshurica.

Typha lepechinii Mavrodiev et Kapit. sp. nov. (Typhaceae Juss.)—A New Endangered Endemic Cattail in the Outmost East of European Russia

Typha lepechinii, a new species from European Russia, is described. In terms of the external morphology, it is similar to T. shuttleworthii but differs from the latter by the shape of female inflorescence, wider leaf blades and geographical distribution. Like T. shuttleworthii, T. lepechinii is clearly distinct from all other cattails of T. sect. Ebracteolatae due to its short male inflorescence that is 2–4 times shorter than the contiguous female inflorescence. The spatial disjunction of this new species from the main distribution range of predominantly European T. shuttleworthii is significant: T. lepechinii is an endemic of the outmost East of the Russian Plain, in particular, the regions of Middle and Southern Cis-Ural region (basin of the Middle and Lower Kama). In terms of the political administrative borders, this new cattail was found in the Udmurt Republic, the Republics of Tatarstan and Bashkortostan, the parts of the Russian Federation. From the elementary comparative molecular standpoint, T. lepechinii is different from its sister T. shuttleworthii due to four single nucleotide positions and two indels of the rpl32 gene and rpl32-trnL intergenic spacer (cpDNA). The new cattail is named after I. I. Lepechin (1737–1802)—a Russian scientist-encyclopedist whose primary botanical interest focused on the regions of Ural and Siberia.

Susceptibility of the Banana Inflorescence to Blood Disease.

The bacterium Ralstonia syzygii subsp. celebesensis causes Blood disease of banana, a vascular wilt of economic significance in Indonesia and Malaysia. Blood disease has expanded its geographic range in the last 20 years and is an emerging threat to Southeast Asian banana production. Many aspects of the disease cycle and biology are not well understood, including the ability of different parts of the female and male inflorescence of banana to act as infection courts. This study confirms that the banana varieties of Cavendish, and Kepok 'Kuning' are susceptible to Blood disease and that an inoculum concentration of 102 CFU/ml of R. syzygii subsp. celebesensis is adequate to initiate disease after pseudostem inoculation. Data show that infection occurs through both the male and female parts of a banana inflorescence and the rachis when snapped to remove the male bell. The infection courts are the female flowers, the male bell bract scar, the male bell flower cushion, the snapped rachis, and deflowered fingers. The location of these infection courts concurs with the dye studies demonstrating that dye externally applied to these plants parts enters the plant vascular system. Thus, the hypothesis is supported that infection of R. syzygii subsp. celebesensis occurs through open xylem vessels of the male and female parts of the banana inflorescence.

Corema album (L.) D. Don Phenological Growth Stages according to Extended BBCH Scale

ABSTRACT The wild dioecious plant Corema album, endemic to the Atlantic coast of the Iberian Peninsula, has potential to become a new crop and to integrate the berry fruit market. Due to its potential, the aim of this study was to propose a BBCH (Biologische Bundesanstalt, Bundessortenamt and CHemical Industry) scale for the species. Based on field observation, the principal growth stages were described and sequentially established. Photographs and stereomicroscope acquisition software were used to illustrate the phenological stages of male and female plants. The scale includes seven principal stages starting with bud development (stage 0), followed by leaf development (Stage 1), main stem elongation (Stage 3), inflorescence emergence (Stage 5), flowering (Stage 6), fruit development (Stage 7) and ending with fruit maturation (stage 8), with mesostages for male and female inflorescence (stage 5) and flower development (stage 6). Through field observations carried out in plants in different growth conditions, the proposition of this extended BBCH scale was made, to have a standardized system for Corema album phenological stages. This study will have an application especially in fields of agronomy and plant breeding and will also be a stepping stone for the inclusion of this species as a novelty crop in a nearby future.

Micro-RNA-Regulated SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE (SPL) Gene Expression and Cytokinin Accumulation Distinguish Early-Developing Male and Female Inflorescences in Oil Palm (Elaeis guineensis).

Sexual differentiation of inflorescences and flowers is important for reproduction and affects crop plant productivity. We report here on a molecular study of the process of sexual differentiation in the immature inflorescence of oil palm (Elaeis guineensis). This species is monoecious and exhibits gender diphasy, producing male and female inflorescences separately on the same plant in alternation. Three main approaches were used: small RNA-seq to characterise and study the expression of miRNA genes; RNA-seq to monitor mRNA accumulation patterns; hormone quantification to assess the role of cytokinins and auxins in inflorescence differentiation. Our study allowed the characterisation of 30 previously unreported palm MIRNA genes. In differential gene and miRNA expression studies, we identified a number of key developmental genes and miRNA-mRNA target modules previously described in relation to their developmental regulatory role in the cereal panicle, notably the miR156/529/535-SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE (SPL) gene regulatory module. Gene enrichment analysis highlighted the importance of hormone-related genes, and this observation was corroborated by the detection of much higher levels of cytokinins in the female inflorescence. Our data illustrate the importance of branching regulation within the developmental window studied, during which the female inflorescence, unlike its male counterpart, produces flower clusters on new successive axes by sympodial growth.

A Selection of Reliable Reference Genes for Gene Expression Analysis in the Female and Male Flowers of Salix suchowensis.

Salix is a dioecious plant. Research on the molecular regulation mechanism of male and female inflorescence differentiation and development is necessary to analyze sex differentiation in the willow and the underlying mechanisms of unisexual flower development. However, at present, there are no reference genes suitable for stable expression in the process of willow inflorescence development. In this study, Salix suchowensis was used as the research material, nine candidate reference genes (α-TUB1, α-TUB2, ACT, H2A, DnaJ, CDC2, GAPDH, TIP41, β-TUB) were selected, and qRT-PCR technology was used to detect the expression of each candidate reference gene in female and male flowers at different developmental stages and using five algorithms (geNorm, Normfinder, Delta Ct, BestKeeper, and RefFinder) to comprehensively evaluate the stability of candidate reference genes. The results showed that ACT and DnaJ were stably expressed in all samples and could be used as reference genes. In addition, the reliability of the screening results was further verified via an expression pattern analysis of the CFS gene that encodes flower specific transcription factor in different samples. The stable reference genes selected in this study provide the basis for future research on the expression analysis of functional genes related to the development of male and female flowers of S. suchowensis.

Composition and Functional Properties of Banana Tree Male Inflorescence Flour

ABSTRACT The purpose of this paper is to physical-chemical characterize of male inflorescence of Prata-Anã and Grande Naine cultivars, and their respective flours. Three drying methods were used to prepare the flours: F1- drying in a forced-air oven at 40°C/30 hours; F2- at 60°C/24 hours and F3- conventional oven at 120°C/45 minutes. The banana tree male inflorescence has a high moisture content, significant amount of fiber and reduced caloric value, cv. Prata-Anã stood out in crude protein and crude fiber values. Grande Naine F2 and F3 flours was higher in antioxidant potential, the F3 flours was better in total phenolics.

Frond Base Fracture and Dynamics of Palm Oil Inflorescence Applied With Different Nutrient Sources

Frond base fracture is an increasingly common phenomenon in oil palm plantations caused by various stress factors. This study aimed to determine the incidence of frond base fracture in the plantation where different nutrient sources were applied (palm oil mill effluent, oil palm EFB, and organic fertilizers) in relation to the dynamics of oil palm inflorescence. The incidence of frond base fracture and the production of male and female inflorescences were observed in 30 sample trees for each nutrient source. Observations were made three times with an interval monthly. To reveal the research objectives, it used descriptive analysis. The results showed that the routine application of POME increased the susceptibility of oil palms to fractured fronds and the sex ratio was higher other than that of EFB; the lowest incidence was found in the palm that was given inorganic fertilizers. frond base fracture trees produced fewer female inflorescence, although the number of male ones did not differ between frond base fracture palm and healthy ones.

Monitoring of mulberry (Morus L.) plantations to identify samples that combine high productivity and decorativeness

Aim. The purpose of the research was to identify unique mulberry specimens in the existing plantations, adapted to the climatic conditions of the growth zone, with a different combination of economic characteristics. The collection of the dendrological park "Ustimivskyi", protective strips within the land use of the Ustymivska Experimental Station of Plant Production of Plant Production Institute nd. a. V. Ya. Yuriev of NAAS, private estates of residents of the villages of Ustymivka and Novobudova of the Globynska UTC of the Poltava region. Results and Discussion. Among the mulberry plants growing in the collection of the Arboretum, one can single out sample УП33 as the sweetest of the examined samples. УП21 has large fruits 2-3 cm long, pale pink, when fully ripe - purple; whole leaf, large, 20-25 cm long, dark green. On the territory of the introduction-quarantine nursery of the station, the sample КР1 grows, which has only male inflorescences and a leaf blade 15-18 cm long and is recommended as a decorative one. In the village Newly, the HC1 sample deserves attention - a tree with dark purple sub-fruits 2.5-3 cm long, the fruits are pleasant to the taste, the leaf is small, leathery. Sample HC2 has white subfruits up to 2 cm long, when fully ripe they are faintly sweet, but without a pronounced specific taste, the leaves are small, smooth on both sides. In 1952-1954, between the fields of the experimental station, for feeding silkworms, a forest strip was planted, where you can distinguish the ЛЯ4 sample with dark purple fruits up to 2 cm long with a neutral, but pleasant taste. In sample ЛЯ5, individual fruitlets in the subfruit are large, red-purple, which remain shiny when overripe. Among the samples growing in the homesteads of the residents of the villages of Ustymivka and Novobudoka, a number of samples can be singled out (УВ7, УВ14, УВ24, УН2, УБ1, НХ1), which combine high taste qualities and the size of the leaf plates. Conclusions. Along with basic varieties and species, seedlings with an interesting combination of economic and valuable traits are growing on the surveyed territories, which deserve further study and use in selection programs and greening of settlements.

Pollinators of oil palm and relationship to fruitset and yield in two fruit forms in Ghana

Oil palm and its pollinators are native to Africa. Notwithstanding, it has been extensively cultivated outside its native range, so also has its pollinators been acquired and introduced. A concern, however is that most documentation on oil palm and its pollinators are non-indigenous, with little information of African origin commenting on their activities in Africa. Thus, a study on the insect pollinators of oil palm was carried out on two fruit forms: Dura and Tenera, (ages ten and seven, respectively), in Ghana. The aim was to understand how average monthly population density of the pollinators relates to one another, and to two bunch parameters (fruitset and fruit-to-bunch ratio). Nine species (all in the order Coleoptera) were consistently seen on the spikelets of anthesising male inflorescences, and eleven species on receptive female inflorescences. Six were of the Elaeidobius genus: E. kamerunicus, E. plagiatus, E. singularis, E. subvittatus, E. bilineatus, and Elaeidobius sp. 1 (unidentified species); two each were of the Microporum genus: M. congolenses, M. dispar, and the Prosoestus genus: P. scuptilis, P. minor; while one species was of either Atheta or Forficula. The pollinators were observed to be positively related, and to varying degree of significance. Fruitset level was acceptably high, indicating adequate pollinator population and efficient pollination. There was a positive relationship between population density of the pollinators and fruitset, and a negative relationship between the bunch parameters. A number of other insects were seldom observed around the male and female inflorescences; their role could not be defined.

Laboratory rearing of Elaeidobius kamerunicus Faust (Coleoptera: Curculionidae) pollinator of oil palm inflorescence in Malaysia

This study was conducted to evaluate laboratory rearing of Elaeidobius kamerunicus through observation of its life development and survivability on an artificial diet and anthesising male inflorescence of oil palm as the natural feed. The experiment was the three adopted diets compared with rearing on natural feed toward the survivability and life development of reared larvae Elaeidobius kamerunicus. The AMI of oil palm was the successful diet for the survival of weevil larvae with around 11 days to develop from egg to adult. The improved natural feed is calculated to have a longer time for 50% mortality than the first natural feed, where it had double the time requirement. Moreover, improving the natural feed rearing method had increased survivability from around 20% to almost 50%. Furthermore, they improve natural feed enables shorter life development at 10 days. Thus, this study provided the method for rearing E. kamerunicus through the natural feed for better key survival and management.

Two New Species of Balanophora (Balanophoraceae) From South China

Abstract— Populations of Balanophora from southern China are often identified by local botanists as B. laxiflora based on their long cylindric male inflorescence, subsessile male flowers with slender rudimentary bracts, and subdiscoid synandria. In this study, we clarify the identity of seven such populations based on morphological characters and phylogenetic analysis using nuclear 18S and ITS ribosomal DNA sequences. We confirmed the occurrence of dioecious populations of B. yakushimensis and two previously unrecognized species, which we describe here as B. parajaponica and B. appressa. Phylogenetic analyses indicated that B. parajaponica, B. yakushimensis, B. appressa, B. laxiflora, and the agamospermic B. japonica, formed a well resolved clade, viz. the B. laxiflora clade. The four dioecious species, although highly similar in the morphology of male inflorescence and flowers, can be separated by leaf morphology and arrangement, ovary color, and arrangement of female flowers. The species limit of B. laxiflora, however, remains unresolved.

Refinement of the methodology for assessing the resistance of hazel (hazelnuts) to stress factors

The aim of the research is to clarify the methodology for assessing the resistance of hazel (hazelnuts) to stress factors on the basis of uniform approaches adopted in walnut farming. The assessment of resistance to biotic and abiotic factors has been carried out according to the methods recommended for the walnut, and the state of the vegetative and generative organs of hazel (hazelnuts) has been correlated with the program requirements. The result has been the development of 7 point assessment scales and the numerical values of the degree of damage correlated with them. Score 0 corresponds to the absence of lesions, 1 – lesions up to 5%, 2 – lesions up to 6–10%, 3 – lesions up to 11–25%, 4 – lesions up to 26–50%, 5 – lesions up to 51–75%, 6 – lesions more than 75% or death of the whole plant (depending on the studied indicator). The assessment scale for the winter hardiness of vegetative organs takes into account the degree of damage to the apical buds, annual shoots, branches of two years and older, the stem and the whole plant. Damage to male inflorescences is determined by the length of their dead part, to the female flowers – by the number of damaged ones, expressed as a percentage. The degree of drought resistance is revealed on the basis of studying the state of the entire plant, the percentage of damaged and fallen leaves. The influence of drought on the loss of food part is established by the degree of shrinkage of the kernel. Susceptibility to diseases and pests is estimated in percentage points separately for leaves by area, shoots in length, nuts by the ratio of damaged and undamaged ones. We have distinguished 6 groups of resistance, depending on the degree of vulnerability of varieties and forms of hazel (hazelnuts). It has been proposed to draw conclusions on the basis of at least three years of observations, and the final conclusion should be focused on specific breeding goals.

Evaluation of the antibacterial activity of <em>Borassus flabellifer</em> male inflorescence against selected human pathogenic bacteria

The Sri Lankan Journal of Infectious Diseases (SLJID) is an open access, peer-reviewed, biannual journal published by the Sri Lankan Society for Microbiology (SSM). The Journal considers articles from all professional disciplines involved in the field of infectious diseases. The Journal has been in publication since 2011, is included in the DOAJ since 2018 and is a member of COPE since 2021. The SLJID practices a double-blind peer review policy. From 2022, the SLJID publishes accepted manuscripts online immediately after copy-editing, enabling rapid dissemination of scientific knowledge. The published articles are subsequently compiled into two issues in April and October. The SLJID does not charge any article processing or publication fee.

Flowering and fruiting phenology of jackfruit (Artocarpus heterophyllus Lam.) from Sumatra landraces in ex situ conservation area in Karangmojo, Yogyakarta

This study aimed to determine the flowering and fruiting phenology of jackfruit originated from Sumatra landraces planted in ex situ conservation in Yogyakarta within the 2018 and 2019 flowering periods. Flowering ontogeny and phenology were observed following Owens and Pushpakumara methods. Results found five developmental stages of male inflorescences, which last in 64-101 days, ended by the drought and abscissed of the males. Female inflorescences undergo five stages which take 92-160 days in total. Differences in rainfall and the dry season period resulted in different onset and duration of flowering. In 2018, which has more rainfall and a shorter dry season, flowering initiates lately (February-June) with a longer duration (6 months). In 2019, the less rainfall and more extended dry season resulted in early flowering (January-April) with a shorter duration (4 months). The Medan landrace flowered later and longer. Flowering synchrony occurred between sexes within the same tree, but there was asynchronous flowering among individual trees. Water availability is crucial in flowering and fruit production. Flowering stimulation and pollination management may also be conducted to increase flower production, pollinating agents, and fruit production and synchronize the flowering.

Cultivation Trial of an Edible and Medicinal Mushroom Species, Pleurotus Tuber-regium (Rumph. ex Fr.) Singer 1951 (strain 190212) on Various Lignocellulosic Substrates

In Central Africa, mushrooms are critically important non-timber forest products (NTFPs), both nutritionally and economically. A strain of edible and medicinal lignicolous fungus, Pleurotus tuber-regium (Rumph. ex Fr.) Singer 1951 (strain 190212), isolated from tissue (sclerotia), on PDA medium, was tested on corn grain and sawdust seedling substrates and on palm oil male inflorescence (Elaeis guineensis Jacq.), ground corn (Zea mays L) stalks and grass (Paspalum notatum L) soaked for 24 hrs then drained for 24 hours, and unsoaked ground corn (Zea mays L) stalks. The highest mycelial growth rate recorded was about 0.9 cm on the PDA medium; 5.97 cm on the corn-based seedling medium and 11.95 cm on the sawdust-based seedling medium. Total mycelial invasion on the PDA medium was observed on day 10, day 14 on the corn-based seedling medium, and day 24 on the sawdust-based seedling medium. The onset of mycelial invasion was noticeable on day 3 of seeding for all treatments T0 (control), T1 (Final substrate based on soaked ground corn stalks), T2 (Final substrate based on unsoaked ground corn stalks), and T3 (Final substrate based on turf). Total invasion of mycelium was obtained at day 15 of incubation for treatments T1 and T2, at day 18 for treatment T3 and at day 24 for treatment T0. The results obtained on treatments T1 and T2 respectively (14.95±3.12% and 15.65±1.06%) of the maize stalk substrate, lead us to believe that the strain 190212 of Pleurotus tuber-regium species used has adapted and requires an improvement of the medium with nitrogen-rich additives such as soybean meal. This could achieve the theoretical yield of 20% or more, according to which a substrate can be considered better in producing sporophores.

Elaeidobius kamerunicus (Coleoptera: Curculionoidea): Activity on Oil Palm Flower in Central Kalimantan, Indonesia.

<b>Background and Objective:</b> <i>Elaeidobius kamerunicus </i>Faust (Coleoptera: Curculionoidea) is a weevil pollinator oil palm flower, <i>Elaeis guineensis</i> Jacq. (Arecales: Arecaceae) Jacq. Male and female inflorescences attracted the weevil, male inflorescences appeared to provides nectar and pollen but female inflorescences seemed provides the weevils with nectar. The objective of this research was to determine the dynamics of<i> E. kamerunicus </i>activity in pollinating oil palm flowers in Kumai, Central Kalimantan, Indonesia. <b>Materials and Methods:</b> The population of <i>E. kamerunicus </i>that visited male flowers was calculated by taking a sample of 9 spikelets from male inflorescences, while the number of <i>E. kamerunicus </i>that come to female inflorescence was calculated by counting the weevil around the flower. <b>Results:</b> The results of this study showed that peak activity of <i>E. kamerunicus</i> on oil palm flowers<i> </i>occurred between 11.00-12.45. The male flowers blossomed occurred for 6-7 days to complete their inflorescence, while those of the females completed their cycle for 4-5 days. The oviposition of <i>E. kamerunicus </i>females fluctuated from 05.00-18.00. The number of females oviposits in the flower peaked at 09.00. Temperature and maximum light intensity had a positive correlation with the overall density of <i>E. kamerunicus</i> and oviposition by female weevils. The Minimum light intensity affects the abundance and visitation of <i>E. kamerunicus</i> on oil palm flowers. <b>Conclusion:</b> The abundance of <i>E. kamerunicus</i> population in Kumai was established and could give possibility resulting in the better fruit set of oil palm. Conservation efforts can be conducted by maintaining the abundance of the population, especially on the days and hrs of peak abundance of weevils.

High Phenotypic Plasticity in a Prominent Plant Invader along Altitudinal and Temperature Gradients.

Studies on plant growth and trait variation along environmental gradients can provide important information for identifying drivers of plant invasions and for deriving management strategies. We used seeds of the annual plant invader Ambrosia artemisiifolia L. (common ragweed) collected from an agricultural site in Northern Italy (226 m. a.s.l; Mean Annual Air Temperature: 12.9 °C; precipitations: 930 mm) to determine variation in growth trajectories and plant traits when grown along a 1000-m altitudinal gradient in Northern Italy, and under different temperature conditions in the growth chamber (from 14/18 °C to 26/30 °C, night/day), using a non-liner modeling approach. Under field conditions, traits related to plant height (maximum height, stem height, number of internodes) followed a three-parameter logistic curve. In contrast, leaf traits (lateral spread, number of leaves, leaf length and width) followed non-monotonic double-Richards curves that captured the decline patterns evident in the data. Plants grew faster, reaching a higher maximum plant height, and produced more biomass when grown at intermediate elevations. Under laboratory conditions, plants exhibited the same general growth trajectory of field conditions. However, leaf width did not show the recession after the maximum value shown by plants grown in the field, although the growth trajectories of some individuals, particularly those grown at 18 °C, showed a decline at late times. In addition, the plants grown at lower temperatures exhibited the highest value of biomass and preserved reproductive performances (e.g., amount of male inflorescence, pollen weight). From our findings, common ragweed exhibits a high phenotypic plasticity of vegetative and reproductive traits in response to different altitudes and temperature conditions. Under climate warming, this plasticity may facilitate the shift of the species towards higher elevation, but also the in situ resistance and (pre)adaptation of populations currently abundant at low elevations in the invasive European range. Such results may be also relevant for projecting the species management such as the impact by possible biocontrol agents.

Flowering and quality of seeds and pollen in endangered populations of Betula humilis

Key messageLowered pollen and seed quality of B. humilis compared to its widespread tree relatives may threaten its populations at the southwestern edge of the species range.Inability to produce vital propagules is the main threat to the persistence of rare plants at the edges of species distribution. In the present investigation, factors responsible for the low germinability of shrub birch (Betula humilis) seeds in the peripheral populations were analysed. As shrub birch populations are found in phosphorus (P)-limited peatlands with high groundwater levels, the impact of groundwater PO43− ion contents and groundwater table for B. humilis flowering was also studied. Qualities of the B. humilis seeds and pollen were compared to those of tree congeners silver birch (B. pendula) and downy birch (B. pubescens), which usually represent a high reproductive performance. We revealed that the poor germination ability of B. humilis seeds was caused by the high proportions of empty seeds (44.8%) and seeds with partially developed embryos (47.3%). The insufficient numbers of viable seeds may be a consequence of low-quality shrub birch pollen, as only 1.6% of pollen grains sprouted. The germinability of shrub birch pollen was significantly lower than that of Betula tree pollen; thus, there is a risk of pollination of B. humilis female flowers by pollen grains of tree birches. Positive relationships between the P concentrations in seeds and seed germinability were revealed in tree birches, but not in B. humilis. The availability of PO43− ions in the groundwater did not affect B. humilis flowering, but male inflorescences were more numerous in stands with higher groundwater levels. Consequently, the maintenance of peatlands is crucial for the efficient sexual reproduction of shrub birches.

Phosphorus in Oil Palm Cultivated in the Oriental Amazon

Amazon soils have a low phosphorus (P) availability and few studies have investigated nutrition of palm oil plantations. This study assessed the effects of P nutrition on oil palm organs according to plant age. The experiment was carried out under field conditions, at the enterprise Agropalma S/A, in the municipality of Tailândia, Pará State, Brazil. The experimental design used was completely randomized with four replications and comprised seven treatments: plants age (2, 3, 4, 5, 6, 7, and 8 years of planting). We evaluated P concentration, accumulation, and exportation in plant components (leaflets, petioles, stipe, rachis, palm heart, arrows, male inflorescences, peduncles, spikelets, and fruits). Palm heart (10.9 g kg-1) and male inflorescence (3.8 g kg-1) showed the highest P concentrations in the vegetative and reproductive organs, respectively. On the other hand, the largest P accumulations were observed in the stipe (159 g plant-1) and fruits (59 g plant-1), increasing from the 3rd year of age of the plants. Bunches exported the largest P amounts (81 g plant-1), especially in older plants. The oil palm immobilizes (24 kg ha-1) and recycles (23 kg ha-1) a large amount of P, more than it exports (12 kg ha-1) P.