Mean Leaf Research Articles

Multiple stressors in multiple species: Effects of different RDX soil concentrations and differential water-resourcing on RDX fate, plant health, and plant survival.

Response to simultaneous stressors is an important facet of plant ecology and land management. In a greenhouse trial, we studied how eight plant species responded to single and combined effects of three soil concentrations of the phytotoxic munitions constituent RDX and two levels of water-resourcing. In an outdoor trial, we studied the effects of high RDX soil concentration and two levels of water-resourcing in three plant species. Multiple endpoints related to RDX fate, plant health, and plant survival were evaluated in both trials. Starting RDX concentration was the most frequent factor influencing all endpoints. Water-resourcing also had significant impacts, but in fewer cases. For most endpoints, significant interaction effects between RDX concentration and water-resourcing were observed for some species and treatments. Main and interaction effects were typically variable (significant in one treatment, but not in another; associated with increasing endpoint values for one treatment and/or with decreasing endpoint values in another). This complexity has implications for understanding how RDX and water-availability combine to impact plants, as well as for applications like phytoremediation. As an additional product of these greenhouse and outdoor trials, three plants native or naturalized within the southeastern United States were identified as promising species for further study as in situ phytoremediation resources. Plumbago auriculata exhibited relatively strong and markedly consistent among-treatment mean proportional reductions in soil RDX concentrations (112% and 2.5% of the means of corresponding values observed within other species). Likewise, across all treatments, Salvia coccinea exhibited distinctively low variance in mean leaf chlorophyll content index levels (6.5% of the means of corresponding values observed within other species). Both species also exhibited mean wilting and chlorosis levels that were 66% and 35%, and 67% and 84%, of corresponding values observed in all other plants, respectively. Ruellia caroliniensis exhibited at least 43% higher mean survival across all treatments than any other test species in outdoor trials, despite exhibiting similar RDX uptake and bioconcentration levels.

Tree Surface Temperature in a Primary Tropical Rain Forest

As one of the important factors affecting plant productivity and plant distribution, temperature also affects the physiological and ecological characteristics of plants to a large extent. We report canopy leaf temperature distribution over a 36 m tall primary tropical rain forest and samplings of 28 tree species in SW China by means of two high resolution thermal cameras (P25, Flir systems, Wilsonville, OR, USA). The leaf temperature of dominant tree Species Pometia tomentosa was the highest (31.8 °C), 10.2 °C higher than that of tree species Mezzettipsis creaghii (21.6 °C). The mean leaf to air temperature difference (Tc–Ta) of Pometia tomentosa was the highest (6.4 K), the second highest was Barringtonia pendula (6.1 K), and Mezzettipsis creaghii had the lowest (Tc–Ta) (1.9K). (Tc–Ta) of tree species with smaller leaves and larger stomatal conductance was lowly sensitive to climate factors. Leaf size and stomatal conductance together decided the effect of climate change to (Tc–Ta) of the different tree species. We have shown that the composition of tree species in tropical rain forest areas is important to the climate through our research.

Responses of leaf morphology, NSCs contents and C:N:P stoichiometry of Cunninghamia lanceolata and Schima superba to shading

BackgroundThe non-structural carbohydrates (NSCs), carbon (C), nitrogen (N), and phosphorus (P) are important energy source or nutrients for all plant growth and metabolism. To persist in shaded understory, saplings have to maintain the dynamic balance of carbon and nutrients, such as leaf NSCs, C, N and P. To improve understanding of the nutrient utilization strategies between shade-tolerant and shade-intolerant species, we therefore compared the leaf NSCs, C, N, P in response to shade between seedlings of shade-tolerant Schima superba and shade-intolerant Cunninghamia lanceolate. Shading treatments were created with five levels (0, 40, 60, 85, 95% shading degree) to determine the effect of shade on leaf NSCs contents and C:N:P stoichiometry characteristics.ResultsMean leaf area was significantly larger under 60% shading degree for C. lanceolata while maximum mean leaf area was observed under 85% shading degree for S. superba seedlings, whereas leaf mass per area decreased consistently with increasing shading degree in both species. In general, both species showed decreasing NSC, soluble sugar and starch contents with increasing shading degree. However shade-tolerant S. superba seedlings exhibited higher NSC, soluble sugar and starch content than shade-intolerant C. lanceolate. The soluble sugar/starch ratio of C. lanceolate decreased with increasing shading degree, whereas that of S. superb remained stable. Leaf C:N ratio decreased while N:P ratio increased with increasing shading degree; leaf C:P ratio was highest in 60% shading degree for C. lanceolata and in 40% shading degree for S. superba.ConclusionS. superba is better adapted to low light condition than C. lanceolata through enlarged leaf area and increased carbohydrate reserves that allow the plant to cope with low light stress. From mixed plantation viewpoint, it would be advisable to plant S. superba later once the canopy of C. lanceolata is well developed but allowing enough sunlight.

Armut Fidanlarının Morfolojik Özellikleri Üzerine Anaçların ve Çeşitlerin Etkisi

Meyve yetiştiriciliğinde anaçlar üzerine aşılanan çeşidin büyüme ve gelişmesini etkilediği gibi çeşitler de üzerlerine aşılandıkları anacı etkilemektedirler. Günümüzde armut yetiştiriciliği farklı büyüme özelliklerine sahip anaçlar üzerine aşılanarak çoğaltılan fidanlar ile yapılmaktadır. Bitkilerin kök sistemini oluşturacak olan anaçların seçimi çeşit seçimi kadar önemlidir. Bu çalışma, aşılı armut fidanlarının morfolojik özellikleri üzerine bazı armut klon anaç ve çeşitlerinin etkisini belirlemek amacıyla 2018-2019 yılları arasında yürütülmüştür. Bu çalışmada, ‘Deveci’, ‘Williams’, ‘Santa Maria’ ve ‘Abate Fetel’ armut çeşitleri Fox9, Fox11, OHxF87 ve OHxF333 armut klon anaçları üzerine dilciksiz aşı yöntemiyle aşılanmıştır. Araştırmada fidanlarda anaç çapı (mm), aşı noktası çapı (mm), aşı sürgününde yan dal sayısı (adet), boğum sayısı (adet), boğum arası mesafe (cm), yaprak eni ve boyu (cm), yaprak sapı uzunluğu (cm) ve kalınlığı (mm), sürgündeki yaprak sayısı (adet), ortalama ve toplam yaprak alanı (cm2) incelenmiştir. Araştırmada tüm parametreler üzerine anaçların ve çeşitlerin değişen düzeylerde etkiye sahip olduğu saptanmıştır. En yüksek aşı noktası çapı anaçlar bakımından Fox9; çeşitler bakımından ‘Deveci’de belirlenmiştir. Araştırmada en fazla yan dal sayısı ve yaprak sayısı Fox9 üzerine aşılı ‘Deveci’ çeşidinde tespit edilmiştir. Ortalama yaprak alanı en fazla ‘Santa Maria’, bitki başına toplam yaprak alanı ise ‘Deveci’ çeşidinde belirlenmiştir. Sürgündeki boğum sayısının Fox9 anacında diğer anaçlardan daha yüksek olduğu belirlenmiştir. Boğum arası mesafenin Fox9 anacında diğer anaçlardan daha düşük olduğu saptanmıştır. ‘Santa Maria’ çeşidinde boğum arası mesafenin diğer çeşitlerden daha yüksek olduğu tespit edilmiştir. Bu araştırmanın sonucunda morfolojik özellikler bakımından Fox9 anacı üzerine aşılı ‘Deveci’ çeşidinin diğer çeşit/anaç kombinasyonlarından daha iyi değerlere sahip olduğunu söyleyebiliriz.

Primary production in forests of the mangrove palm Nypa fruticans

We investigated the forest structure, leaf demography, leaf allometry and growth of the erect canopy of the mangrove palm Nypa fruticans in four river systems distributed over 10 degrees of latitude in the tropics of northeast Australia and Papua New Guinea to obtain estimates of aboveground biomass (AGB) and annual aboveground net primary production (ANPP). In the four river sites Nypa mean leaf and tree densities ranged from 6538 to 12,200 leaves ha−1, and 1526 to 3550 trees ha-1 and differed significantly among sites, with the lowest densities at the lowest latitude site. AGB ranged from 36.5 to 55.7 Mg ha−1 and also differed among sites with the lowest AGB at the lowest latitude site. The mean plastochron increased with increasing periods of cooler air temperatures. Mean litter production per tree (range, 6.0–16.2 kg year−1) was least in the low latitude site and mean total productivity per tree (range, 13.9–25.1 kg year−1) did not differ significantly across sites. ANPP was lowest in the low latitude site and ranged from 23.8 to 60.9 Mg ha−1 year−1. This placed Nypa forests in the mid to high range of global estimates of ANPP. Rates of litter production at three sites (range, 25.7–37.5 Mg ha−1 year−1) was much greater than for litterfall in any other mangrove forest. ANPP estimated using a combination of demographic data and leaf allometry compares well with previous estimates using a light interception method to predict productivity. The complex pattern of differences in forest structure, growth and ANPP across latitudes likely represent differences in catchment land use, successional stages of forests, river discharge and variation in the length of the dry season.

Canopy photosynthesis of six major arable crops is enhanced under diffuse light due to canopy architecture.

Diffuse radiation generally increases photosynthetic rates if total radiation is kept constant. Different hypotheses have been proposed to explain this enhancement of photosynthesis, but conclusive results over a wide range of diffuse conditions or about the effect of canopy architecture are lacking. Here, we show the response of canopy photosynthesis to different fractions of diffuse light conditions for five major arable crops (pea, potato, wheat, barley, rapeseed) and cover crops characterized by different canopy architecture. We used 13years of flux and microclimate measurements over a field with a typical 4year crop rotation scheme in Switzerland. We investigated the effect of diffuse light on photosynthesis over a gradient of diffuse light fractions ranging from 100% diffuse (overcast sky) to 11% diffuse light (clear-sky conditions). Gross primary productivity (GPP) increased with diffuse fraction and thus was greater under diffuse than direct light conditions if the absolute photon flux density per unit surface area was kept constant. Mean leaf tilt angle (MTA) and canopy height were found to be the best predictors of the diffuse versus direct radiation effect on photosynthesis. Climatic factors, such as the drought index and growing degree days (GDD), had a significant influence on initial quantum yield under direct but not diffuse light conditions, which depended primarily on MTA. The maximum photosynthetic rate at 2,000µmolm-2 s-1 photosynthetically active radiation under direct conditions strongly depended on GDD, MTA, leaf area index (LAI) and the interaction between MTA and LAI, while under diffuse conditions, this parameter depended mostly on MTA and only to a minor extent on canopy height and their interaction. The strongest photosynthesis enhancement under diffuse light was found for wheat, barley and rapeseed, whereas the lowest was for pea. Thus, we suggest that measuring canopy architecture and diffuse radiation will greatly improve GPP estimates of global cropping systems.

Gender-related responses of dioecious plant Populus cathayana to AMF, drought and planting pattern

In our previous studies, we detected drought, gender and arbuscular mycorrhizal (AM) inoculation effects on dioecious plant. Based on this, we investigated the intra- and inter-sexual competition between male and female plants. Dioecious plant Populus cathayana was used and we set 3 factors in this experiment: (1) AM inoculation/non-inoculation; (2) well-watered/water-stressed; (3) single-gender pattern (only 4 males or 4 females)/mixed-gender pattern (2 males and 2 females). Growth (stem length, ground diameter, SPAD, mean leaf area, biomass accumulation) and nutrition (C, N, P, K, Ca and Mg) distribution of male and female seedlings were determined. Results Drought significantly limited plant growth and nutrition accumulation, especially in female plants; AM formation alleviated this negative effect, especially in male plants. However, the gender effect was complicated. A mixed-gender planting pattern relieved intra- competition in terms of the growth and nutrient accumulation of both genders and even alleviated the negative effects caused by drought. In the mixed-gender pattern, the differences of C, N, P, K and Ca contents between male and female plants with AM inoculation was smaller than those without AM inoculation, which indicated a potential role for AM fungi in nutrient transport. Males had a stronger physiological response to limited water availability, and more advantages from AM formation than females. Mixed-gender planting relieved the existence of intra- sexual competition of dioecious plants, and AM symbiosis alleviated the differences between genders.

Effects of Seed Size on the Germination and Early Growth of African Baobab (Adansonia digitata L.)

The effects of seed size on the germination and early growth of A. digitata were assessed. Seeds were sourced locally within the University of Ilorin Campus. One hundred viable seeds were selected from each of the size classes. The seed weight, length, breadth, and width were measured for all the selected seeds. Mean weight, length, breadth, and thickness were: 0.62 g, 9.16 mm, 7.45 mm, and 5.85 mm, respectively for small seeds. 0.41 g, 9.54 mm, 7.68 mm, and 6.03 mm, respectively for medium seeds; and 0.44 g, 9.92 mm, 7.89 mm, and 6.21 mm, respectively for large seeds. The experiment was laid out in a completely randomized design (CRD). Seed dormancy was broken through the acid scarification method by soaking in H2SO4 at 70% concentration for 20 minutes with constant stirring. Variables of interest include: leaves number, seedlings height, collar diameter and leaf area. Based on the results of this finding, medium and large seeds germinated in 7 days after sowing while small seeds germinated in 10 days after sowing. Large seeds had the highest germination percentage (55%), followed by medium seeds with 27%. The small seeds were the least in terms of germination rate (21%). There was no significant difference in mean seedling heights, collar diameters and number of leaves among the seed size classes (P˃0.05). Mean leaf area significantly differed among the three size classes (P˂0.05). The result showed that large seeds gave best germination at a shorter period than the medium and small seed sizes. Thus, large seeds of A. digitata are recommended in propagation activities involving the species.

Genetic improvement in glory lily (Gloriosa superba L.): A review

Glory lily (Gloriosa superb L.) is an herbaceous perennial climber belonging to the family Liliaceae. Its tuber and seeds contain an alkaloids viz., cochicine and colchicoside; among which colchicine act as an anti-mitotic agent used for inhibiting mitotic cell division. The variability of genetic stocks could be increased by increasing the collection from diversified origin and geographical distribution. The phenotypic and genotypic variances, estimated from the total variance were used to assess the variability among the genotypes. The genotypic coefficient of variance helps to measure the range of diversity in a character and provides the means to compare genetic variability in quantitative characters. The genotypic coefficient of variance along with phenotypic coefficient of variation was used to ascertain the value of diversity among the genotypes. The variability study revealed that higher phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were recorded for fresh seed yield per plant, dry seed yield per plant and fresh pod yield per plant. The higher estimates of heritability and genetic advance as per cent of mean were obtained for number of leaves, fresh pod yield and fresh seed yield. Thus, selection for these traits is likely to accumulate more additive genes leading to further improvement in their performance. In context to the associations between characters; positive phenotypic and genotypic correlations of dry seed yield were found with plant height, days to 50% flowering, number of flowers per plant, number of pods per plant, pod length, fresh pod yield per plant and fresh seed yield per plant. These correlated yield components suggested that it may be good selection criteria to improve seed yield of this crop. The traits viz., total sugar, mean leaf area, leaf area index and relative water content exhibited negatively and non-significantly correlation with dry seed yield per plant both at phenotypic and genotypic levels. Fresh seed yield per plant had highest positive effect on seed yield followed by number of pods per plant and fresh seed weight per pod. These yield components suggested that it may be good selection criteria to improve seed yield of glory lily crop. Gloriosa superba usually multiply by corm and seeds but due to low germination capability it restricts for the regeneration. Therefore, in order to safeguard and preserve this important plant biotechnological approach would be very useful. Different workers suggested different protocols for in vitro regeneration of plant. Now a day’s molecular diversity also play a vital role in crop improvement programme. RAPD and SSR markers were frequently used to identify molecular diversity in this crop.

Biometric characteristics of fruits and leaves of Cornus officinalis Siebold et Zucc. genotypes in the M.M. Gryshko National Botanical Garden of the NAS of Ukraine

In the context of global climate change, the current strategy of agroeconomics focuses on the introduction of unique plant species and the selection of new commercially important cultivars adapted to the dramatic weather changes. Cornus officinalis (Cornaceae) has Chinese origin, its reintroduction at the M.M. Gryshko National Botanical Garden, National Academy of Sciences of Ukraine started in 1993.
 The objectives of this research were: to investigate the biometric parameters of fruits and leaves of C. officinalis genotypes, C. officinalis × C. mas hybrid ‘Etude’ and genotype from the grafting C. officinalis on C. mas under cultivation in the M.M. Gryshko National Botanical Garden, National Academy of Sciences of Ukraine, and to determine the degree of adaptation of C. officinalis to the climatic conditions of Ukraine (in particular, Right-Bank Forest Steppe) for selection of promising genotypes for further breeding work.
 Material and methods. We used: a) 26-year-old maternal plant obtained from a two-year-old seedling in 1993 received from the nursery “Northwoods Wholesale Nursery” Mollala (Oregon, USA), where it was grown as an ornamental plant; b) seedlings of the maternal plant; c) cultivar Etude, which is an artificial hybrid from crossing C. officinalis × C. mas; and d) genotype obtained from grafting C. officinalis on C. mas. In our experiment, the maternal plant is indicated as G-01, while other plants – as G-02–G-08 genotypes. We determined the biometric parameters of the fruit (length, diameter, and weight), endocarp (length, diameter, and weight), pedicel (length and thickness), leaf blade (length, width, and the number of lateral veins) and petiole (length, width, and thickness). We examined the dynamics of fruit and endocarp formation during the season (genotypes G-01–G-03 and G-05) and compared the biometric characteristics of the fruit of genotypes G-01–G-05 from crops of two years, 2010 and 2018, which were most favorable in weather conditions. We have processed quantitative data in the PAST 2.10 software. The differences between the samples were estimated using the Tukey-Kramer test. The degree of variability was determined by the coefficient of variation. To assess the level of variability, we used the classification of Mamaev (1975).
 Results. We have found that the largest fruits in 2010 were observed in the genotype G-01 and the smallest – in the genotype G-03. The coefficient of variation of the linear parameters of the fruit and endocarp was in the range 5.7–10.1 %; the level of variability was very low or low. The variability of fruit weight and endocarp was high; the coefficient of variation was from 7.0 up to 28.3 %. The amplitude of the linear parameters of the leaf was wide (coefficient of variation was from 9.8 to 31.0 %). The cultivar Etude differed from other C. officinalis genotypes in size and weight of (M = 1800 mg, max = 2400 mg) and a much wider amplitude of variation in the length (17.9–22.6 vs. 14.3–18.2 mm) of the fruit. The largest leaves were in the genotypes G-08 and G-01, and the smallest – in the genotype G-02. The cultivar Etude did not differ so much by the mean leaf morphometric indices and number of veins, but it demonstrated one of the broadest leaf blades (51.5 mm).
 Conclusions. The data obtained in this study is important for the commercial use of C. officinalis and the cultivar Etude as food and medicinal plant, as well as for breeding in climatic conditions of Ukraine and analysis of hybridization features in the genus Cornus in general.

CLIMATIC INFLUENCES ON LEAF FALL SEASONALITY IN THE ATLANTIC FOREST (SERRA DOS ÓRGÃOS NATIONAL PARK – RJ- BRAZIL)

We compare temporal variations in leaf fall among three sites of evergreen Atlantic Forest and analyze how climatic variables influence it. Sites were located at Serra dos Orgaos National Park at different altitudes. Litter was collected monthly, from September 1997 to September 2005. Leaves were separated from other litter elements, oven-dried and weighted. Differences in leaf fall mass among grids and how they correlated with temporal variations were analyzed. Climatic variables were obtained from a nearby station and deviations from climatological normals were analyzed. We grouped climatic variables using Principal Component Analyses (PCA) and the highest scores of the two main factors were selected to construct regression models for different time lags. Leaf fall represented 50.5-70 percent of the total litter fall and mean leaf fall differed significantly among grids. However, leaf fall seasonality in the three areas were correlated. Leaf fall increased at the end of dry periods, when temperature and precipitation started to increase. Climatic variables were classified into two groups: seasonal and anomaly. Models constructed with lag variation from 0 and 6 months show that leaf fall was best explained by an anomaly in the maximum mean temperature, with lag 0, and by precipitation, with a six-month lag. We conclude that plant species respond immediately to drastic deviations from climatic factors, while regular climatic conditions are responsible for the seasonality of leaf fall, most likely as a late response to water shortage at the end of the dry season. .

Influence of biosurfactant producing Bacillus tequilensis LK5.4 isolate of kinema, a fermented soybean, on seed germination and growth of maize (Zea mays L.).

In this study, the lipopeptide biosurfactant was extracted, purified and characterized from the Bacillus isolate LK5.4 obtained from kinema samples of Sikkim. Plant growth-promoting property of the biosurfactant producing bacterium was also evaluated. Out of fifty-seven isolates, only ten were biosurfactant producer as determined by the oil displacement test. Bacillus isolate LK5.4 showed the maximum emulsification index (52.3 ± 0.02), reduced surface tension up to 40% and produced 754mgL-1 biosurfactant in the nutrient broth. Based on 16S rRNA gene sequencing, the isolate LK5.4 was identified as B. tequilensis. Biosurfactant was purified by Thin Layer Chromatography (TLC). Evaluation of the chemical characteristics by TLC, Liquid Chromatography-Mass Spectrometry, Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance Spectroscopy identified the biosurfactant as surfactin. The effect of different concentration of biosurfactant in maize seed germination was evaluated under in vitro condition. It showed the fastest growth of seedlings at 300µg/ml biosurfactant solution. Similar results were shown by the potted plant experiment, where the soil was directly treated with biosurfactant producing bacterium LK5.4. The LK5.4 treated plants showed a mean height of 29.17 ± 0.47cm and mean leaf length of 18.42 ± 0.17cm while the mean height and mean length of the leaf were 15.48 ± 0.98cm and 11.12 ± 0.40cm respectively in the control plants. The treated plants had higher moisture content (68.48 ± 2.79%) than the control plants (50.53 ± 1.63%), which is because of higher bioadsorption in the treated plants. These results provided indirect evidence of plant growth-promoting property of the biosurfactant.

A general formula for calculating surface area of the similarly shaped leaves: Evidence from six Magnoliaceae species

Leaf area is an important indicator of photosynthetic capacity in plants. Knowledge of the variation of leaf shape at an individual level or a population level can help by accurately calculate leaf area. Such calculations can help us to understand the life history strategies of plants, and allow us to better understand the influence of climate change on mean leaf area as an indicator of leaf size, which is closely related to stand yields and ecological ecosystem services. The Montgomery equation (ME), which describes a proportional relationship between leaf surface area and the product of leaf length and width, has been demonstrated to hold true for many broad-leaved plants. The Magnoliaceae family has 17 genera covering ca. 300 species, of which some plants play important roles in the landscape. Many Magnoliaceae plants have similar leaf shapes, and little is known about whether ME can act as a general formula to calculate leaf surface area for these plants. This paper provides the evidence that ME can be used to measure the leaf area of Magnoliaceae species. More than 2500 mature leaves of six species within two genera (Magnolia and Michelia) of the Magnoliaceae family were selected as samples. The data of leaf length, width, and area were obtained from the scanned images. We used four models to fit these data, including (1) ME (which is actually a direct proportional function of leaf area vs. the product of leaf length and width), (2) a power-law function between leaf area and the product of leaf length and width, (3) a power function with an exponent of 2 between leaf area and leaf length, and (4) a power function between leaf area and leaf length. We found that ME and the second function have similar root-mean-square error values that are both lower than those of the other two equations. However, ME is better than the second equation because of the simplicity of its structure. We documented the validity of ME for calculating leaf area at a species level, a genus level, and even for the 6-species pooled data set. The estimated Montgomery parameter (i.e., the proportional coefficient in ME) is approximately equal to 0.68, which means that leaf area of the six investigated species can be approximated by 68% of the area of a rectangle with the leaf’s length and width as its sides. This study provides a convenient and fast approach for leaf-area calculation. In addition, we found that the Montgomery parameter can act as an indicator for measuring the similarity of leaves among different species, which provides a measurement standard for leaf morphology.

Litterfall production and associated carbon and nitrogen flux along exclosure chronosequence at Kewet district, central lowland of Ethiopia

BackgroundLitterfall input and associated nutrient flux are critically important in the restoration of soil in degraded landscapes through exclosures. This study was conducted to evaluate the effects of exclosure on seasonal litterfall production and nutrient content, and estimate annual C and N inputs to the soil in an age sequence at Kewet district, central lowland of Ethiopia. Leaf litterfall production was recorded by a 0.25 m2 litter trap from a systematically laid line transects from 5, 15, and 20 years old exclosures and adjacent grazing land.ResultsLeaf litterfall input in the exclosures ranged from 37 g m−2 in January (at the old exclosure) to 7.33 g m−2 (at the young exclosure), and 3 g m−2 in March at the grazing land. Litterfall input showed seasonal variation and peaked in the dry months. Mean monthly leaf litterfall production was significantly (p <0.05) higher (22 g m−2) in the old exclosure than the adjacent grazing land (9 g m−2). Total annual leaf litterfall ranged from 1073 kg ha−1 (grazing land) to 2662 kg ha−1 (old exclosure). There were no significant differences in leaf litterfall nutrients i.e., N, P, K, Ca, and Mg concentrations, except for C. The annual leaf litterfall associated C and N input ranged from 412 (grazing land) to 1025 (old exclosure) and 27 (middle age exclosure) to 68 kg ha−1 (old exclosure), respectively. The positive change recorded in leaf litterfall production and associated C and N return is associated with restoration of vegetation.ConclusionsThrough well-managed area exclosure, leaf litterfall production in the degraded landscapes can reach the level of tropical dry lowland forest in about a decade. Further research on the contribution of dominant tree species in litter production along the age of exclosure is recommended to improve the effectiveness of rehabilitation of degraded lands.

Canopy structure and understory light characteristics of a natural Quercus aliena var. acuteserrata forest in China northwest: Influence of different forest management methods

Close-to-nature forest management (CNFM), structure-based forest management (SBFM), and secondary forest comprehensive silviculture (SFCS) are three forest management methods that have been promoted in China. Unfortunately, changes to the canopy structure and understory light characteristics after forest management remain unclear. We compared the canopy structure and light characteristics of a natural Quercus aliena var. acuteserrata forest under the four management methods of CNFM, SBFM, SFCS and unmanaged control (CK) after four years of using the WinScanopy instrument. The results suggest that (1) the leaf area index (LAI) values in the CNFM and SBFM were higher than that in the CK, the mean leaf angle (MLA) value in the SBFM was significantly lower than that in the CK. (2) The values of total under radiant energy (TU) and directed radiant energy (Dir) in the SFCS were significantly higher than that in the CK, while the values of diffused radiant energy (Dif) in the CNFM and SBFM were significantly lower than that in the CK. The extinction coefficient (EC) value in three forest management measure was significantly lower than that in the CK. (3) The canopy structure was sensitive to changes in tree crowding, and the light characteristics were sensitive to changes in forest layer numbers, LAI and CO, which explained 81.19% and 94.88% of the total variations in the canopy structure and light characteristics, respectively. Thus, CNFM and SBFM altered the canopy structure, which may be attributed to the LAI that was influenced by tree crowding, and the three forest treatments altered the understory light environment, which may be influenced mainly by the canopy structure. CNFM and SBFM increased the leaf area index of the stand and improved the understory light environment in a natural Quercus aliena var. acuteserrata forest.

Stemflow estimation models for Japanese cedar and cypress plantations using common forest inventory data

Although stemflow (SF) had been regarded as a small portion of the gross rainfall (GR), recent studies have revealed that, depending on the forest stand structure, the SF/GR ratio should not be neglected. This study derived SF/GR estimation models using common forest inventory data. A set of SF/GR ratio and forest inventory data (stand density (SD), total basal area (BA), mean diameter at breast height (DBH¯), mean tree height (H¯), canopy cover (CC), and leaf area index (LAI)) was collected from previous studies of Japanese cedar and cypress plantations. To further investigate the relation between SF/GR ratio and forest stand structures, we examined additional stand-structure variables (mean basal area (BA¯), mean stem surface area (SA¯), and total stem surface area (SA)) derived from the inventory data, and the stand-scale funneling ratio (FRstand) evaluating the efficiency of funneling rainwater. Among all the stand-structure variables, SD exclusively determined the SF/GR ratio, providing the best-fitting positive single linear regression equation as a density-based SF/GR model with a root mean square error (RMSE) of 2.4%. Although this model is useful for practical forest water management because it requires only SD which is the most basic forest inventory data, it has a weak point in meticulous forest water management because it cannot reflect the effect of tree growth on SF/GR ratio. Thus, we developed a size-based SF/GR model (RMSE = 2.0%) based on the strong relationship between the FRstand and DBH¯. This model is applicable to meticulous forest water management because it reflects the effects of not only SD but also tree growth by DBH on SF/GR ratio. These models derived from the common forest inventory data are potentially applicable to the evaluation and control of SF in forest water management.

EEG Functional Connectivity Underlying Emotional Valance and Arousal Using Minimum Spanning Trees

In recent years, traditional methods such as power spectrum and amplitude analysis have been used to research the emotional electroencephalogram (EEG). The brain network method is also used in emotional EEG research, which can better reflect the activity of brains. A minimum spanning tree (MST) represents the key information flow in the weighted brain network, and it provides a sensitive method to capture subtle information in network organization while effectively avoiding the shortcomings of traditional brain networks. The DEAP dataset provides electroencephalogram (EEG) data for four categories of emotions: high arousal and high valence (HAHV), high arousal and low valence (HALV), low arousal and high valence (LAHV), and low arousal and low valence (LALV). Phase lag index (PLI) weighted matrices were calculated in five frequency bands. On this basis, the minimum spanning trees were constructed. At the same valence level in the gamma (γ) band, HAHV and HALV showed significant higher mean PLI (MPLI), maximum degree (Degreemax) and leaf fraction and significant lower diameter and eccentricity than LAHV and LALV. At the same arousal level in the γ band, HALV showed significant higher MPLI, Degreemax and leaf fraction and significant lower diameter and eccentricity than HAHV. These results indicate that the low-arousal showed more line-shaped configurations than the high-arousal. Additionally, in the high-arousal condition, a shift toward more star-shaped trees from high-valence to low-valence supports the trend toward randomness of the brain network with negative emotions and that the brain is more activated when faced with negative emotions. From a brain network perspective, this phenomenon provides a theoretical basis for negative bias.

Fungicide Application Timing Essential for the Management of Leaf Spot and Fruit Rot on Pomegranate (Punica granatum L.) in Florida.

Pomegranate (Punica granatum L.) has emerged as an alternative fruit crop for growers dealing with devastating threats to citrus and avocado in the southeastern United States. However, foliar and fruit diseases are major constraints to commercial pomegranate production. Replicated field trials were performed in 2015 at three separate sites in Florida (Dover, Plant City, and Parrish) to evaluate Merivon (pyraclostrobin and fluxapyroxad), Luna Experience (fluopyram + tebuconazole), and a rotational program consisting of these two fungicides as well as Penncozeb 75DF (mancozeb) for the management of leaf spot and fruit rot of pomegranate. The fungicide programs were evaluated on the varieties Vietnam in Dover, FL; Angel Red in Plant City, FL; as well as Christina, Azadi, Vikusnyi, Alsirinnar, Sakerdze, and Wonderful in Parrish, FL. Mean leaf spot severity varied across sites at the end of each trial in August, with values ranging from 4.5 to 62.5% in Plant City, 7.5 to 45.8% in Dover, and 4.5 to 54.2% in Parrish. Based on area under the disease progress curve, all treatments that included at least one at bloom application significantly reduced disease levels compared with postbloom treatments and the nontreated control across all trial sites. Based on fruit rot incidence, Luna Experience and Merivon, when applied twice at bloom in the beginning of the season, reduced disease by 66.6 and 88.4%, respectively, in comparison with the nontreated control in Plant City. A rotational program further reduced disease by at least 97% at the end of the season in Parrish. The proper timing of fungicide application and rotation with different modes of action provided a feasible disease management option for pomegranate growers in the Southeast United States.

Unraveling the habitat preferences of two closely related bumblebee species in Eastern Europe.

Co‐occurrence of closely related species is often explained through resource partitioning, where key morphological or life‐history traits evolve under strong divergent selection. In bumble bees (genus Bombus), differences in tongue lengths, nest sites, and several life‐history traits are the principal factors in resource partitioning. However, the buff‐tailed and white‐tailed bumble bee (Bombus terrestris and B. lucorum respectively) are very similar in morphology and life history, but their ranges nevertheless partly overlap, raising the question how they are ecologically divergent. What little is known about the environmental factors determining their distributions stems from studies in Central and Western Europe, but even less information is available about their distributions in Eastern Europe, where different subspecies occur. Here, we aimed to disentangle the broad habitat requirements and associated distributions of these species in Romania and Bulgaria. First, we genetically identified sampled individuals from many sites across the study area. We then not only computed species distributions based on presence‐only data, but also expanded on these models using relative abundance data. We found that B. terrestris is a more generalist species than previously thought, but that B. lucorum is restricted to forested areas with colder and wetter climates, which in our study area are primarily found at higher elevations. Both vegetation parameters such as annual mean Leaf Area Index and canopy height, as well as climatic conditions, were important in explaining their distributions. Although our models based on presence‐only data suggest a large overlap in their respective distributions, results on their relative abundance suggest that the two species replace one another across an environmental gradient correlated to elevation. The inclusion of abundance enhances our understanding of the distribution of these species, supporting the emerging recognition of the importance of abundance data in species distribution modeling.

Comparative studies on nutrients need and uptake in Khaya senegalensis seedlings

This study examine comparative studies on nutrients needs and uptake in K. senegalensis seedlings to evaluate effect of organic manure (Cow dung; 20g, 10g; Poultry manure: 20g, 10g; Water hyacinth 20g, 10g and control). The variables measured were plant height, collar diameter and leaf numbers. The experiment was laid out in a Completely Randomized Design (CRD), the data collected were subjected to Analysis of Variance (ANOVA) and Means separation using Least Significant Difference (LSD). The results showed that seedlings grown with cow dung of 20g produced the highest mean height (12.45cm), collar diameter (5.68mm) and leaf production (7). The best performance was observed in seedlings grown with cow dung at the rate of 20g. 20g of cow dung mixed with 2kg of forest top soil can therefore be used to raise K. senegalensis seedlings for good growth in the Nursery.&#x0D; Keywords: Nutrients, Khaya senegalensis, organic manure, nursery , water hyacinth