Grass Leaf Research Articles

Effects of Varying Levels of Lemon Grass Leaf Meal on Performance, Haematology and Serum Biochemical Indices of Broilers

A total of two hundred unsexed broiler chicks aged two weeks were used for six weeks feeding trial to evaluate growth performance, hematology, and serum biochemistry. In this study, broilers chicks were fed dietary lemon grass leaf meal at inclusion levels of T1control (0.00%), T2 (1.50%), T3 (2.25%) and T4 (3.75 %). The weighed broilers were distributed at random among the four treatment diets. A completely randomized experimental design was used, and each treatment was replicated five times with ten broilers per replicate. Experimental birds were provided experimental starter and finisher diets ad-libitum throughout the experimental period at weeks 2 to 4 and 5 to 7 respectively. The experiment revealed that weekly feed intake for week 2, 3, 4 and 6 was significantly affected (P<0.05) except week five. The daily weight gain followed similar pattern, however significant difference were observed only in week 3, 4 and 7 in all the treatment groups. There were significant (P<0.05) differences among the dietary groups in week 4, 6 and 7 in terms of feed conversion ratio. White blood cells value of birds fed on control diet 286.07x 109 /dl is similar to 283.37 and 268.67x 109 /dl for T3 and T4. Neutrophil values 14%, 19%,18% and 20% for T1, T2, T3 and T4 were statistically significant (P<0.05) indicating that birds were challenged with increasing levels of lemon grass leaf meal beyond 3.75%. The results of this study indicate that birds fed with 1.5% of dietary lemon grass meal was the best among diets with lemon grass and comparable with the control group in terms of daily weight gain. This implies that birds fed with 1.5% level lemon grass leaf meal (LGLM) was able to utilize the experimental diet better than other treatment groups and without detrimental effects.

Immunoglobulin E-specific allergens against leaf in serum of dogs with clinical features of grass leaf allergy.

Grass leaf has been suspected of causing immunoglobulin (Ig)E-mediated immediate hypersensitivity reactions in humans and dogs. However, most studies in this area are case-control studies without in vitro data showing the involvement of IgE in the reaction. Laboratory studies have demonstrated the reactivity to a 50-55 kDa protein with clinical signs immediately after contact with grass leaf material. The clinical findings of dogs with atopic-like dermatitis immediately after contact with grass leaf material suggest the involvement of grass leaves as the allergen source. This study was designed to test the IgE-reactivity of grass leaf proteins in dogs with clinical signs and positive scratch test results against grass leaf material. The serum of 41 patients with a history of allergy and suspected to grass leaf material was immunoblotted against grass leaf extracts from five suspected grass species. The IgE-positive blots were separated with 2D gel electrophoresis and analysed with mass spectrometry (MS). Commercially supplied proteins were used to validate immunoblot activity. The serum of 25 dogs diagnosed with grass dermatitis had positive IgE-specific immunoblot against one or more grass leaf extracts. The MS data indicated a reactive band at 55 kDa to be beta-amylase or RuBisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) large subunit (RbLS). All tested dog sera showed IgE-reactivity with beta-amylase and some with RbLS. Canines with clinical signs of grass-related dermatitis had IgE-reactivity against grass leaf proteins. Serum IgE-reactivity to beta-amylase and RuBisCO large subunit may indicate that these proteins act as allergens, possibly causing pruritus and skin lesions.

A Wox3-patterning module organizes planar growth in grass leaves and ligules

Grass leaves develop from a ring of primordial initial cells within the periphery of the shoot apical meristem, a pool of organogenic stem cells that generates all of the organs of the plant shoot. At maturity, the grass leaf is a flattened, strap-like organ comprising a proximal supportive sheath surrounding the stem and a distal photosynthetic blade. The sheath and blade are partitioned by a hinge-like auricle and the ligule, a fringe of epidermally derived tissue that grows from the adaxial (top) leaf surface. Together, the ligule and auricle comprise morphological novelties that are specific to grass leaves. Understanding how the planar outgrowth of grass leaves and their adjoining ligules is genetically controlled can yield insight into their evolutionary origins. Here we use single-cell RNA-sequencing analyses to identify a ‘rim’ cell type present at the margins of maize leaf primordia. Cells in the leaf rim have a distinctive identity and share transcriptional signatures with proliferating ligule cells, suggesting that a shared developmental genetic programme patterns both leaves and ligules. Moreover, we show that rim function is regulated by genetically redundant Wuschel-like homeobox3 (WOX3) transcription factors. Higher-order mutations in maize Wox3 genes greatly reduce leaf width and disrupt ligule outgrowth and patterning. Together, these findings illustrate the generalizable use of a rim domain during planar growth of maize leaves and ligules, and suggest a parsimonious model for the homology of the grass ligule as a distal extension of the leaf sheath margin.

Hormonal control of medial-lateral growth and vein formation in the maize leaf.

Parallel veins are characteristic of monocots, including grasses (Poaceae). Therefore, how parallel veins develop as the leaf grows in the medial-lateral (ML) dimension is a key question in grass leaf development. Using fluorescent protein reporters, we mapped auxin, cytokinin (CK), and gibberellic acid (GA) response patterns in maize (Zea mays) leaf primordia. We further defined the roles of these hormones in ML growth and vein formation through combinatorial genetic analyses and measurement of hormone concentrations. We discovered a novel pattern of auxin response in the adaxial protoderm that we hypothesize has important implications for the orderly formation of 3° veins early in leaf development. In addition, we found an auxin transport and response pattern in the margins that correlate with the transition from ML to proximal-distal growth. We present evidence that auxin efflux precedes CK response in procambial strand development. We also determined that GA plays an early role in the shoot apical meristem as well as a later role in the primordium to restrict ML growth. We propose an integrative model whereby auxin regulates ML growth and vein formation in the maize leaf through control of GA and CK.

Microbial carbon use efficiency of litter with distinct C/N ratios in soil at different temperatures, including microbial necromass as growth component

An incubation study was carried out to investigate the effects of litter quality, i.e. 15 N-labelled maize (C/N of 25.5) and Rhodes grass (C/N of 57.8) leaf litter on microbial carbon use efficiency (CUE) and priming effects in a moderate alkaline soil at two different temperatures (15 and 25 °C). CUE values were calculated from the isotopic composition of the particulate organic matter (POM) recovered as an index for the amount of non-decomposed litter. This approach allows the inclusion of microbial necromass growth components in the calculation of CUE values. Additionally, the soil was incubated for 10, 20, and 30 days to determine the optimum incubation period. Soil microbial CUE values of maize and Rhodes grass leaf litter, including microbial necromass C in the calculation of CUE, varied around 0.61, regardless of litter type, temperature, and incubation period. However, the optimum incubation time is between 20 and 30 days, depending on temperature. The strong priming effect on autochthonous soil organic carbon (SOC) mineralization was apparently not caused by N mining, as it was similar for both litter qualities. It most likely resulted from SOC being used by microbial co-metabolism. The litter-induced true priming effect was accompanied by a significant increase in autochthonous POM. The current approach, including microbial necromass as growth component, has been shown to be a strong tool for investigating CUE values and priming effects after application of litter and harvest residues to soil, probably under all environmental conditions.

Mathematical Modelling of Drying Characteristics of Lemon Grass Leaves (Cymbopogon citratus)

Drying characteristics of Lemon grass leaves using an oven dryer was studied at four different temperatures (40, 50, 60 and 70°C). The effect of the drying temperatures on moisture content of the leaves was investigated. Thirteen drying models were fitted to the drying data to establish the model that best describes the drying characteristics of Lemon grass leaves. The best model was determined by the model with the lowest value of SSE and root mean square error (RMSE), and the highest value of coefficient of determination (R2). Hii et al. model satisfied the conditions for selecting the most suitable and reliable model with R2, SSE and RMSE values of the model was 0.9964, 0.0250 and 0.0214 respectively. This model is most suitable at 40°C. The effective diffusivity (Deff) values ranged from 8.92452 × 10-12 m2/s to 16.00657 × 10-12 m2/s and increases as temperature increases. It was further observed that the amount of energy required to eliminate moisture within the leaves was in the range of 19.85 kJ/mol - 19.86949 kJ/mol. Dried lemongrass leaves can be used in food preservation as an alternative to synthetic substances that have recently become less acceptable to consumers. Consumers accept natural food products that are universally acknowledged as safe, such as lemon grass with essential oils, and they also fit the standards for green processing.

Sheathed Blades: Subtle tweaks to common genetic patterns explain key grass leaf structure.

Sheathed Blades: Subtle tweaks to common genetic patterns explain key grass leaf structure.

Disturbance to biocrusts decreased cyanobacteria, N-fixer abundance, and grass leaf N but increased fungal abundance.

Interactions between plants and soil microbes influence plant nutrient transformations, including nitrogen (N) fixation, nutrient mineralization, and resource exchanges through fungal networks. Physical disturbances to soils can disrupt soil microbes and associated processes that support plant and microbial productivity. In low resource drylands, biological soil crusts ("biocrusts") occupy surface soils and house key autotrophic and diazotrophic bacteria, non-vascular plants, or lichens. Interactions among biocrusts, plants, and fungal networks between them are hypothesized to drive carbon and nutrient dynamics; however, comparisons across ecosystems are needed to generalize how soil disturbances alter microbial communities and their contributions to N pools and transformations. To evaluate linkages among plants, fungi, and biocrusts, we disturbed all unvegetated surfaces with human foot trampling twice yearly from 2013-2019 in dry conditions in cyanobacteria-dominated biocrusts in the Chihuahuan Desert grassland and shrubland ecosystems. After 5 years, disturbance decreased the abundances of cyanobacteria (especially Microcoleus steenstrupii clade) and N-fixers (Scytonema sp., and Schizothrix sp.) by >77% and chlorophyll a by up to 55% but, conversely, increased soil fungal abundance by 50% compared with controls. Responses of root-associated fungi differed between the two dominant plant species and ecosystem types, with a maximum of 80% more aseptate hyphae in disturbed than in control plots. Although disturbance did not affect 15 N tracer transfer from biocrusts to the dominant grass, Bouteloua eriopoda, disturbance increased available soil N by 65% in the shrubland, and decreased leaf N of B. eriopoda by up to 16%, suggesting that, although rapid N transfer during peak production was not affected by disturbance, over the long-term plant nutrient content was disrupted. Altogether, the shrubland may be more resilient to detrimental changes due to disturbance than grassland, and these results demonstrated that disturbances to soil microbial communities have the potential to cause substantial changes in N pools by reducing and reordering biocrust taxa.

Soil Nitrogen Treatment Alters Microbiome Networks Across Farm Niches.

Agriculture is fundamental for food production, and microbiomes support agriculture through multiple essential ecosystem services. Despite the importance of individual (i.e., niche specific) agricultural microbiomes, microbiome interactions across niches are not well-understood. To observe the linkages between nearby agricultural microbiomes, multiple approaches (16S, 18S, and ITS) were used to inspect a broad coverage of niche microbiomes. Here we examined agricultural microbiome responses to 3 different nitrogen treatments (0, 150, and 300 kg/ha/yr) in soil and tracked linked responses in other neighbouring farm niches (rumen, faecal, white clover leaf, white clover root, rye grass leaf, and rye grass root). Nitrogen treatment had little impact on microbiome structure or composition across niches, but drastically reduced the microbiome network connectivity in soil. Networks of 16S microbiomes were the most sensitive to nitrogen treatment across amplicons, where ITS microbiome networks were the least responsive. Nitrogen enrichment in soil altered soil and the neighbouring microbiome networks, supporting our hypotheses that nitrogen treatment in soil altered microbiomes in soil and in nearby niches. This suggested that agricultural microbiomes across farm niches are ecologically interactive. Therefore, knock-on effects on neighbouring niches should be considered when management is applied to a single agricultural niche.

Evolution of the grass leaf by primordium extension and petiole-lamina remodeling.

The sheathing leaf found in grasses and other monocots is an evolutionary innovation, yet its origin has been a subject of long-standing debate. Here, we revisit the problem in the light of developmental genetics and computational modeling. We show that the sheathing leaf likely arose through WOX-gene-dependent extension of a primordial zone straddling concentric domains around the shoot apex. Patterned growth within this zone, oriented by two polarity fields, accounts for wild-type, mutant and mosaic grass leaf development, whereas zone contraction and growth remodeling accounts for eudicot leaf development. In contrast to the prevailing view, our results suggest that the sheath derives from petiole, whereas the blade derives from the lamina of the eudicot leaf, consistent with homologies proposed in the 19th century.

A simple method for the application of exogenous phytohormones to the grass leaf base protodermal zone to improve grass leaf epidermis development research

BackgroundThe leaf epidermis functions to prevent the loss of water and reduce gas exchange. As an interface between the plant and its external environment, it helps prevent damage, making it an attractive system for studying cell fate and development. In monocotyledons, the leaf epidermis grows from the basal meristem that contains protodermal cells. Leaf protoderm zone is covered by the leaf sheath or coleoptile in maize and wheat, preventing traditional exogenous phytohormone application methods, such as directly spraying on the leaf surface or indirectly via culture media, from reaching the protoderm areas directly. The lack of a suitable application method limits research on the effect of phytohormone on the development of grass epidermis.ResultsHere, we describe a direct and straightforward method to apply exogenous phytohormones to the leaf protoderms of maize and wheat. We used the auxin analogs 2,4-D and cytokinin analogs 6-BA to test the system. After 2,4-D treatment, the asymmetrical division events and initial stomata development were decreased, and the subsidiary cells were induced in maize, the number of GMC (guard mother cell), SMC (subsidiary mother cell) and young stomata were increased in wheat, and the size of the epidermal cells increased after 6-BA treatment in maize. Thus, the method is suitable for the application of phytohormone to the grass leaf protodermal areas.ConclusionsThe method to apply hormones to the mesocotyls of maize and wheat seedlings is simple and direct. Only a small amount of externally applied substances are needed to complete the procedure in this method. The entire experimental process lasts for ten days generally, and it is easy to evaluate the phytohormones’ effect on the epidermis development.

Determining the speed and acceleration of the separator for grass leaf part in horizontal and vertical directions

Vitamin-grass flour is the main component of mixed fodders intended for all types of livestock and poultry. Earlier and currently, the vitamin-grass flour has been prepared from legumes by a high-temperature drying technique. However, existing techniques have high operating costs and require very expensive technical tools. To reduce the specific operating costs and the price of equipment in the production of VGF, a technique has been proposed that involves the main drying of grass to a moisture content of 30‒35 % on a swath while the post-drying of grass is performed in a small-sized channel under the haystack without air heating. Next, the dried mass is pre-crushed. At the same time, the delicate leaf part of the hay, while falling between the side walls of hammers and counter-hammers, is ground and finely crushed, and the stems are processed into large fractions. From pre-crushed hay, the leaf part is separated and fed into the crusher to produce flour. In this case, the main machine that determines the performance of the line is the separator of the leaf part of the grass. The results of the theoretical research have established the speed and acceleration of hay movement on the surface of the sieve. These values determine the productivity of separation of the leaf part from pre-crushed hay and the reliability of the selected structural and technological scheme of the separator. The production tests have confirmed the reliability and economic efficiency of the proposed technique. Comparing the proposed technique for obtaining vitamin-grass flour by existing high-temperature methods has shown that the carotene content in flour was 1.6 times higher while the specific operating costs and equipment price were 6‒7 times lower

Leaf Water Storage and Robustness to Intermittent Drought: A Spatially Explicit Capacitive Model for Leaf Hydraulics.

Leaf hydraulic networks play an important role not only in fluid transport but also in maintaining whole-plant water status through transient environmental changes in soil-based water supply or air humidity. Both water potential and hydraulic resistance vary spatially throughout the leaf transport network, consisting of xylem, stomata and water-storage cells, and portions of the leaf areas far from the leaf base can be disproportionately disadvantaged under water stress. Besides the suppression of transpiration and reduction of water loss caused by stomatal closure, the leaf capacitance of water storage, which can also vary locally, is thought to be crucial for the maintenance of leaf water status. In order to study the fluid dynamics in these networks, we develop a spatially explicit, capacitive model which is able to capture the local spatiotemporal changes of water potential and flow rate in monocotyledonous and dicotyledonous leaves. In electrical-circuit analogs described by Ohm's law, we implement linear capacitors imitating water storage, and we present both analytical calculations of a uniform one-dimensional model and numerical simulation methods for general spatially explicit network models, and their relation to conventional lumped-element models. Calculation and simulation results are shown for the uniform model, which mimics key properties of a monocotyledonous grass leaf. We illustrate water status of a well-watered leaf, and the lowering of water potential and transpiration rate caused by excised water source or reduced air humidity. We show that the time scales of these changes under water stress are hugely affected by leaf capacitance and resistances to capacitors, in addition to stomatal resistance. Through this modeling of a grass leaf, we confirm the presence of uneven water distribution over leaf area, and also discuss the importance of considering the spatial variation of leaf hydraulic traits in plant biology.

Potential roles of selected forage grasses in management of fall armyworm (Spodoptera frugiperda) through companion cropping.

Production of maize, Zea mays L. (Poaceae), in sub‐Saharan Africa is threatened by a new invasive pest, fall armyworm (FAW), Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae). To mitigate this threat, push–pull companion cropping, a system originally developed for management of lepidopteran stemborers, may be used to control FAW. The original system involved trap crops that functioned as a ‘pull’ component to attract moths away from the main crop. How grass species can be used as trap crops in a push–pull system to control FAW is a question that remains to be answered, because maize is already a highly preferred host plant. Therefore, we tested oviposition preference of FAW female moths in no‐choice and two‐choice experiments and larval performance on six selected grasses (Poaceae) to assess their roles as trap crop ‘pull’ plants in the system. In no‐choice tests, numbers of eggs deposited on Brachiaria brizantha (Hochst. ex A. Rich.) R. Webster cv. ‘Piata’, cv. ‘Mulato II’, and cv. ‘Xaraes’, and Napier grass (Pennisetum purpureum K. Schumach) cv. ‘South Africa’ were not statistically different from those deposited on maize. In two‐choice tests between grasses and maize, there were no significant differences in number of eggs laid when the plants were of the same size. However, in two‐choice tests with maize plants half of the size of the grasses, significantly more eggs were laid on B. brizantha cv. Xaraes and P. purpureum cv. South Africa than on maize, suggesting that crop phenology could make a difference. Numbers of larvae arrested on grass leaf cuts were considerably lower than those on maize leaf cuts after 48 h. In two‐choice tests with maize, molasses grass (Melinis minutiflora P. Beauv.) was the only grass that was significantly preferred to maize for larval settlement after 24 h. After 48 h in the two‐choice test, it was the only grass that retained larvae, although the larval count was significantly lower than on maize. Our data show that none of the grasses tested were strongly preferred to maize, but the results indicate plants attractive to FAW adults and larvae that could be utilized in a multiple trap crop approach to target various stages of the pest. Furthermore, results indicate the importance of planting these companion plants earlier than maize.

Kadar Serat, Aktivitas Antioksidan, Karakteristik Fisik Dan Sensoris Yoghurt Susu Kecambah Kedelai Dengan Penambahan Ekstrak Cincau Hijau

Fermented soybean sprouted milk (yogurt) has components that play a role in health. The physical and functional characteristics of soybean sprouted milk yogurt can be improved by the addition of local ingredients, including green grass leaf . This study aims to determine the effect of adding green grass leaf extract on fiber content, antioxidant activity , the physical and sensory characteristics of soybean sprouted yogurt. The research design used a completely randomized design (CRD) with 4 treatments, namely the proportion of addition of grass leaf extract: 1, 3, 5, and 7 percent and 1 control without the addition of love leaf extract. Repetitions were carried out 5 times. Analyzes were carried out on the levels of fiber, antioxidants, physical characteristics (pH and viscosity) and sensory (color, aroma, taste and consistency) of yogurt. The results showed that the addition of green grass jelly leaf extract to soybean sprouted milk yogurt had an effect on fiber content, antioxidant activity and physical characteristics (pH and viscosity) but green did not affect sensory characteristics.

Developmental and biophysical determinants of grass leaf size worldwide.

One of the most notable ecological trends-described more than 2,300years ago by Theophrastus-is the association of small leaves with dry and cold climates, which has recently been recognized for eudicotyledonous plants at a global scale1-3. For eudicotyledons, this pattern has been attributed to the fact that small leaves have a thinner boundary layer that helps to avoid extreme leaf temperatures4 and theirleaf development results in vein traits that improve water transport under cold or dry climates5,6. However, the global distribution of leaf size and its adaptive basis have not been tested in the grasses, which represent a diverse lineage that is distinct in leaf morphology and that contributes 33% of terrestrial primary productivity (including the bulk of crop production)7. Here we demonstrate that grasses have shorter and narrower leaves under colder and drier climates worldwide. We show that small grass leaves have thermal advantages and vein development that contrast with those of eudicotyledons, but that also explain the abundance of small leaves in cold and dry climates. The worldwide distribution of leaf size in grasses exemplifies how biophysical and developmental processes result in convergence across major lineages in adaptation to climate globally, and highlights the importance of leaf size and venation architecture for grass performance in past, present and future ecosystems.

\u03b42Hn-alkane and \u03b418Osugar biomarker proxies from leaves and topsoils of the Bale Mountains, Ethiopia, and implications for paleoclimate reconstructions

The hydrogen isotopic composition of leaf wax–derived n-alkane (δ2Hn-alkane) and oxygen isotopic composition of hemicellulose–derived sugar (δ18Osugar) biomarkers are valuable proxies for paleoclimate reconstructions. Here, we present a calibration study along the Bale Mountains in Ethiopia to evaluate how accurately and precisely the isotopic composition of precipitation is imprinted in these biomarkers. n-Alkanes and sugars were extracted from the leaf and topsoil samples and compound–specific δ2Hn-alkane and δ18Osugar values were measured using a gas chromatograph–thermal conversion–isotope ratio mass spectrometer (GC–TC–IRMS). The weighted mean δ2Hn-alkane and δ18Osugar values range from − 186 to − 89‰ and from + 27 to + 46‰, respectively. Degradation and root inputs did not appear to alter the isotopic composition of the biomarkers in the soil samples analyzed. Yet, the δ2Hn-alkane values show a statistically significant species dependence and δ18Osugar yielded the same species–dependent trends. The reconstructed leaf water of Erica arborea and Erica trimera is 2H– and 18O–enriched by + 55 ± 5 and + 9 ± 1‰, respectively, compared to precipitation. By contrast, Festuca abyssinica reveals the most negative δ2Hn-alkane and least positive δ18Osugar values. This can be attributed to “signal–dampening” caused by basal grass leaf growth. The intermediate values for Alchemilla haumannii and Helichrysum splendidum can be likely explained with plant physiological differences or microclimatic conditions affecting relative humidity (RH) and thus RH–dependent leaf water isotope enrichment. While the actual RH values range from 69 to 82% (x̄ = 80 ± 3.4%), the reconstructed RH values based on a recently suggested coupled δ2Hn-alkane –δ18Osugar (paleo–) hygrometer approach yielded a mean of 78 ± 21%. Our findings corroborate (i) that vegetation changes, particularly in terms of grass versus non–grassy vegetation, need to be considered in paleoclimate studies based on δ2Hn-alkane and δ18Osugar records and (ii) that the coupled δ2Hn-alkane –δ18Osugar (paleo–) hygrometer approach holds great potential for deriving additional paleoclimatic information compared to single isotope approaches.

Rock Water as a Key Resource for Patchy Ecosystems on Shallow Soils: Digging Deep Tree Clumps Subsidize Surrounding Surficial Grass

AbstractMediterranean mountainous areas of shallow soil often display a mosaic of tree clumps surrounded by grass. The combined role and dynamics of water extracted from the underlying rock, and the competition between adjacent patches of trees and grass, has not been investigated. We quantified the role rock water plays in the seasonal dynamics of evapotranspiration (ET), over a patchy landscape in the context of current and past seasonal climate changes, and land‐cover change strategies. Soil water budget suggests deep water uptake by roots of trees (0.8–0.9 mm/d), penetrating into the fractured basalt, subsidized grass transpiration in spring through hydraulic redistribution. However, in summer trees used all the rock water absorbed (0.79 mm/d). A 15‐year data set shows that, with increasing seasonal drought‐severity (potential ET/precipitation) to >1.04, the vertical water flux through the bottom of the thin soil layer transitions from drainage to uptake in support of ET. A hypothetical grass‐covered landscape, with no access to deep water, would require 0.68–0.85 mm/d more than is available, forcing shortened growing season and/or reduced leaf area. Long‐term decreasing winter precipitation and increasing spring potential ET suggest drying climate, so far with stable vegetation mosaic but progressively earlier peak of grass leaf area. Intervention policies to increase water yield by reducing tree cover will curtail grass access to rock moisture, while attempting to increase tree‐related products (including carbon sequestration) by increasing forest cover will limit water availability per tree leaf area. Both changes may further reduce ecosystem stability.

Turgor-time controls grass leaf elongation rate and duration under drought stress.

The process of leaf elongation in grasses is characterized by the creation and transformation of distinct cell zones. The prevailing turgor pressure within these cells is one of the key drivers for the rate at which these cells divide, expand and differentiate, processes that are heavily impacted by drought stress. In this article, a turgor-driven growth model for grass leaf elongation is presented, which combines mechanistic growth from the basis of turgor pressure with the ontogeny of the leaf. Drought-induced reductions in leaf turgor pressure result in a simultaneous inhibition of both cell expansion and differentiation, lowering elongation rate but increasing elongation duration due to the slower transitioning of cells from the dividing and elongating zone to mature cells. Leaf elongation is, therefore, governed by the magnitude of, and time spent under, growth-enabling turgor pressure, a metric which we introduce as turgor-time. Turgor-time is able to normalize growth patterns in terms of varying water availability, similar to how thermal time is used to do so under varying temperatures. Moreover, additional inclusion of temperature dependencies within our model pioneers a novel concept enabling the general expression of growth regardless of water availability or temperature.

Responses of pubertal rabbits to dietary supplementation of ginger (Zingiber officinale rosc) rhizome powder

Seventy two (72) sexed crossbred rabbits aged 6 months were used to determine the effect of ginger rhizome powder (GRP) supplementation on reproductive organ and serum sex hormonal characteristics of pubertal rabbits. The experimental rabbits were divided into 2 treatment groups comprising 36 males and 36 females. Each group was divided into 4 dietary treatments (BT1, BT2, BT3 and BT4 ) of 9 animals and replicated thrice with 3 animals per replicate in a completely randomized design (CRD). The animals were fed formulated diet containing 2900 Kcal ME kg-1 and 18% crude protein supplemented with GRP at the rate of 0, 5, 10 and 15 g kg-1 feed respectively. Rabbits in each dietary group were fed 50gms of Guinea grass leaf meal containing 27.6% CF (dry matter basis) occasionally as additional fibre sources. Feed and water were offered ad libitum and the study lasted for 10 weeks. Testosterone values of BT (5.83 ng mL-1) and BT (6.28 ng mL-1) and follicle stimulating hormone (FSH) levels of BT (1.15 mIU mL-1) were significantly influenced (p<0.05) by ginger rhizome powder. Bucks on BT3 and BT4 had lower luteinizing hormone (LH) level than the BT1 bucks. For the females, FSH and LH values ranged significantly (p<0.05) from 0.90 to 2.05 mIU mL-1 and 0.90 to 3.15 mIU mL-1 respectively. The 17â - estradiol and progesterone levels also ranged significantly (p<0.05) from 166.35 to 175.05 pg mL-1 and 15.45 to 16.80 ng mL-1 respectively. Ovarian weight of rabbit on BT was significantly (p<0.05) higher than those on BT1 but similar to those on BT2 and BT4 treatments. It was therefore concluded that the use of ginger rhizome powder in rabbit diets improved the weight of the ovary as well as enhances serum progesterone, estrogen and testosterone levels.