Plant-derived products rely heavily on the availability of phosphorus (P) in the soil. With reserves of P-rocks being limited, there is a growing demand to enhance the efficiency of P utilization by crops. Eucalypts, an important economic crop in many countries, is a source of timber, coal, essence oils, and cellulose. After identifying low P tolerant and susceptible species in a previous study, we explored the various physiological and biochemical responses of these same species to low P availability. The aim was to expand our understanding of how different P-nutrition responses might impact eucalypt wood production and traits related to its quality. Our results indicate that low soil P minimally affects physiological wood parameters in the young trees of Eucalyptus acmenoides, Corymbia maculata, E. grandis, E. globulus, and E. tereticornis. Decreases in cellulose contents and increases in lignin content and syringyl and guaiacyl (S/G) ratios were observed under low P and only in E. acmenoides plants. Wood density remained unaffected in all species. Additionally, bark, stem, and root P concentrations increased under sufficient P conditions in E. globulus, E. grandis, and E. tereticornis. These findings suggest that these plant parts may act as reserve pools of this nutrient.

Lodging is the permanent displacement of stalks due to disrupted secondary cell walls caused by external factors, plant characters and their interaction. Anatomical, morphological and compositional traits are among lodging-inducing plant traits. In comparison with morphological and anatomical features, the correlation of lodging resistance and cell wall composition is not frequently reviewed. In this review, the relation between cell wall composition and lodging resistance of cereal stalks is comprehensively reviewed based on major cell wall components (lignin, cellulose and hemicellulose) and trace minerals. From the body of literatures reviewed across all cereal crops, lignin and cellulose were found to have significant positive correlation with lodging resistance. However, the effect of structural features of cellulose and lignin on lodging resistance was not investigated in most of the studies. This review also highlights the importance of biomass recalcitrance and lodging resistance trade-offs in the spectrum of genetic cell wall modifications.

Lignin is a polyphenolic compound found in plant tissues, especially wood and bark. The lignin content determines the quality of wood biochar in agroecological uses, and is used in the production of synthetic resins and adhesives. Despite its importance in plant physiology and its agricultural and industrial utility, there exists a wide gap of knowledge of lignin contents of tropical hardwood trees of South Asia, except for a few species. We present here the first estimation of lignin content in wood and bark of 48 species from tropical deciduous forests of India. We show that some species are characterized by greater wood lignin (WL) compared with bark lignin (BL) content, contrary to the generalization held for hardwood trees, and suggest a plausible correspondence between the WL to BL ratio and timber quality.

Spreading of pruning waste over the soil surface may increase soil organic carbon, thus improving soil physical properties and serving as a source of nutrients and energy for microbial populations. The aim of this study was to test the effect of the environmental conditions and the biochemical composition of pruning waste from avocado, cherimoya, mango and gardens on their decomposition process in a Mediterranean subtropical climate. Bagged pruning and garden waste were placed on the ground at a distance of 1 m around the trunk of the three trees from each crop. The concentrations in C, N, lignin, cellulose, hemicellulose, other extracts and ash were determined at the beginning of the experiment (T0), after six (T6) and 24 (T24) months in the field. Initially, significant differences were detected for all types of waste, especially in lignin, hemicellulose, cellulose and other extracts. No significant differences were found in the N content and the C content in mango pruning waste was significantly lower than that in avocado. The greatest weight loss recorded at T24 (63.2%) was related to the lower content in lignin, cellulose and other extracts. Weight losses and C concentrations showed negative correlations with lignin content. Despite the intense decomposition of all the waste, between 55 and 36.8% of the original weights were recorded at the end of the experiment. Recalcitrant C could be the result of the lignin concentrating in the case of the garden waste applied to the different crops.

Although lignin has been negatively correlated with neutral-detergent fibre (NDF) digestibility (NDFD) in ruminants and used to predict potential extent of NDF digestion of forages, selection of an analysis, Klason lignin (KL) or acid-detergent lignin (ADL), to describe that the nutritionally relevant lignin has not been resolved. Dismissed as an artifact is the difference between KL and ADL (ΔL). A question is whether ΔL influences NDFD. We evaluated the relationships of ΔL, KL and ADL with NDFD in order to determine the nutritionally homogeneous or heterogeneous nature of KL. Data sets from two laboratories (DS1 and DS2) were used that included ADL, KL and in vitro NDFD at 48 h (NDFD48). DS1 contained seven C3 grasses, seventeen C4 maize forages and nineteen alfalfas, and DS2 had fifteen C3 grasses, eight C4 forages and six alfalfas. Mean ΔL was greater than ADL in C3 and C4 samples and less in alfalfas. Within forage type and laboratory, ΔL was not correlated with NDFD48 (r −0·34–0·49; all P > 0·17). ADL was more consistently correlated with NDFD48 (r −0·47–−0·95; P < 0·01–0·21) than with KL (r 0·03–−0·91; P < 0·01–0·94). ΔL as a proportion of KL was correlated with NDFD48 in C3 and C4 samples (r 0·44–0·76; P < 0·01–0·08). The differing behaviours of ΔL and ADL relative to NDFD48 indicate that KL is a nutritionally heterogeneous fraction, the behaviour of which may vary by forage type and ratios of ADL and ΔL present.

The distribution of lignin, 8-5′ and 8-8′ linked lignin substructure, and noncellulosic polysaccharides in hemp (Cannabis sativa L.) phloem fibers were explored based on histochemical and immunological methods. Ultraviolet absorption and potassium permanganate staining were observed mainly in the compound middle lamella (CML) and S1 layers, and rarely in the G-layer of phloem fibers, suggesting that lignin concentration is high at the CML and S1 layers, and very low at the G-layer of hemp fibers. Acriflavine staining, uniform KM1 labeling (8-5′ linked lignin substructure), and no KM2 labeling (8-8′ linked structure) were observed in the G-layer, suggesting that there is a small amount of lignin-like compound with 8-5′ linked structure in the G-layer. In addition, some fiber cells showed a multilayered structure. Uniform arabinogalactan protein (AGP) labeling was observed on the S1 layers and G-layers using JIM14, but little appeared in the CML of hemp fibers, indicating that these layers of the phloem fibers contain AGP. Immunogold labeling of xylan (LM11) and glucomannan (LM21) showed that xylan and glucomannan were mainly present in the S1 layers and the G-layers, respectively. In some phloem fibers, LM21 immunofluorescence labeling showed multilayered structure, suggesting the heterogeneous distribution of glucomannan.

Chemical modification of kraft lignin from Pinus caribaea (Sénécl.) W.H.G. was performed with cyclic anhydrides (succinic, maleic and glutaric) assisted by microwave radiation. Esterification of the lignin was proven by the mass increase and Fourier Transform Infrared (FTIR) spectroscopy. Aqueous suspensions of bentonite were prepared using unmodified lignin and the corresponding derivatives as dispersants. Suspensions were evaluated in term of stability, viscosity and dispersibility. The esterified derivatives showed better dispersing properties than the neat lignin because the derivatives-based suspensions were less viscous. The dispersing properties of lignin and the esterified derivatives were compared with those of a high-molecular-weight lignin fraction obtained by ultrafiltration. In addition, two commercial lignosulfonate dispersants commonly used for drilling muds were used as references. The high-molecular-weight esterified derivatives proved to be better dispersants than their unfractionated counterparts. In general, the esterified derivatives showed similar properties to those obtained with the commercial dispersants. Modified lignin based on succinic-, maleic- and glutaric-anhydride is expected to play a key role in the design of novel bio-based dispersants for drilling-mud applications.

Established stands of alfalfa (Medicago sativa L.) at two field locations were treated at one date in the fall with pronamide [3,5-dichloro (N-1,1-dimethyl-2-propynil) benzamide] at 0.8 and 1.6 kg ai/ha and at two dates in the spring with sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} at 0.3 and 0.6 kg ai/ha for the control of quackgrass [Agropyron repens (L.) Beauv. # AGRRE]. Herbicide efficacy was compared by measuring botanical and chemical composition and yield of forage. Both chemicals suppressed quackgrass in first-cutting herbage. While sethoxydim at the higher rate was equivalent to pronamide for increasing the proportion of alfalfa in forage, pronamide was superior for increasing seasonal total yield. Late postemergence applications of sethoxydim were more effective for quackgrass regrowth control than earlier spring applications. Controlling quackgrass in late spring resulted in lower crude protein (CP) content in first-cutting forage than did controlling it in fall. Alfalfa competing with untreated quackgrass had a lower CP content than where quackgrass was controlled with herbicides. All herbicide treatments reduced the neutral-detergent fiber (NDF) of the herbage. As measured by the acid-detergent fiber (ADF) concentration of alfalfa, sethoxydim slightly retarded spring growth of the legume.

Shattercane seed survival during soil burial was highly dependent on attached glumes. Shattercane seed tightly enclosed by glumes averaged 5 and 53% germination after 4 mo of winter burial in 1988 and 1989, respectively. Shattercane caryopses (seed without glumes) survival averaged 0.5 and 17% compared to 17 and 41% when treated with seed fungicides in 1988 and 1989, respectively. Shattercane caryopses tannin and lignin contents were higher than for cultivated sorghum caryopses. Glume tannin was four times higher and glume lignin was five times higher than in the caryopsis. Shattercane seed survival was positively correlated with glume tightness, caryopsis lignin, and glume tannin. Tannin and lignin appear to function as barriers to microbial invasion resulting in higher shattercane seed resistance to overwinter demise. Attempts to isolate fungal inhibitors from shattercane seed were unsuccessful.

Early physiological mechanisms that occur in crop plants in response to neighboring weeds are not well understood. In this experiment, it was hypothesized that, in the absence of direct competition for resources, low red to far red ratio (R:FR) reflected from neighboring weeds will modulate the phenylpropanoid pathway, increase hydrogen peroxide (H2O2), and up-regulate the expression of ethylene biosynthesis and auxin transport genes. Laboratory experiments were conducted under conditions of nonlimiting resources using perennial ryegrass as a model weed species. We discovered that the detection by phytochrome (Phy) of low R:FR signals reflected from both biological and nonbiological sources triggered an up-regulation of ethylene biosynthesis genes and stimulated an auxin transport gene. The low R:FR also modulated the phenylpropanoid pathway resulting in a reduction in anthocyanin content and an enhancement of lignin synthesis. The presence of neighboring weeds also caused an accumulation of H2O2 in the first leaf and crown root tissues of the maize seedling. Stomata were observed to be closed as H2O2 accumulated in leaf tissue. This is the first study to report the modulation of phenylpropanoid pathway and the accumulation of H2O2 attributed to low R:FR. We further suggest that these physiological changes that occur in response to early weed competition result in a physiological cost to the crop plant, which contributes to the rapid loss in yield observed in weed competition studies conducted under field conditions.

Wood density and wood chemical traits are strong predictors of tree performance, carbon stock, and wood decomposition, which play important roles in ecosystem processes and carbon and nutrient cycling in forests. However, it remains unknown how root wood traits are related to stem wood traits. We examined the relationships of wood density and wood chemical traits (lignin and nitrogen concentrations, carbon-to-nitrogen ratio) between the stems and coarse roots of 90 individuals representing 53 tropical tree species in Malaysian Borneo. We developed regression equations of each wood trait using the standardized major axis method. Each root wood trait was highly correlated with the corresponding stem wood trait, and most regression equations fitted well (R2 > 0.5). The lignin concentration of roots was significantly greater than that of stems. We conclude that root wood traits can be estimated from the corresponding stem wood traits in South-East Asian tropical trees. Further analysis of coarse root decomposability will provide more accurate estimates of carbon and nutrient fluxes in tropical forest ecosystems.

Confocal Raman microspectroscopy (CRM) has emerged as a powerful approach to visualize the compositional distribution in lignocellulosic biomass of cell walls. In this work, the applicability of CRM for imaging the topochemical correlation between lignin and hydroxycinnamic acids (HCA) in the Miscanthus sinensis internode was explored. Model compound [p-coumaric acid (PCA) and ferulic acid (FA)] analysis indicated that the band region from 1,152 to 1,197 cm−1 can be used to characterize the distribution of HCA. Raman images calculated by integrating over the area intensity of characteristic spectral regions showed heterogeneous distribution of lignin and HCA at cellular and sub-cellular level. When overlaying the Raman image of lignin and HCA distribution, it was found that these two polymers were co-located in the middle lamella and secondary wall of corresponding cells. Raman images for the band intensity ratio (1,173 cm−1/1,603 cm−1) indicated a clear association between lignin and HCA distribution within morphologically distinct cell wall layers of sclerenchyma fibers and the parenchyma. This is the first time that the spatial correlation between lignin and HCA concentration has been illustrated by a microspectroscopy imaging approach. The results are of importance in extending the current understanding of lignin and aromatics topochemistry in herbaceous biomass.

Alkali pretreatment is a promising pretreatment technology that can effectively deconstruct plant cell walls to enhance sugar release performance. In this study, multi-scale visualization of dynamic changes in poplar cell walls during sodium hydroxide pretreatment (2% w/v, 121°C) was carried out by light microscopy (LM), confocal Raman microscopy (CRM) and atomic force microscopy (AFM). LM observations indicated that swelling occurred primarily in the secondary wall (S) but alkali had little effect on the cell corner middle lamella (CCML). Correspondingly, there was a preferential delignification in the S at the beginning of pretreatment, while the level of delignification in CCML (~88%) was higher than that in the S (~83%) for the whole process revealed by Raman spectra. It also suggested that prolonging residence time to 180 min would not remove lignin completely but cause rapid loss of carbohydrates, which was further visualized by Raman spectroscopy images. Furthermore, AFM measurements illustrated that pretreatment with alkali exposed the embedded microfibrils from noncellulosic polymers clearly, enlarged the diameter of microfibrils, and decreased the surface porosity. These results suggested that there was a synergistic mechanism of lignocellulose deconstruction regarding cell wall swelling, main components dissolution, and microfibril morphological changes that occurred during alkali pretreatment.

Intervessel pits play a key role in trees' water transport, lying at the base of drought-induced embolism, and in the regulation of hydraulic conductivity via hydrogels bordering pit canals. Recently, their microstructure has been the focus of numerous studies, but the considerable variation, even within species and the histochemistry of pit membranes, remains largely unexplained. In the present study, intervessel pits of the outermost wood were examined for Avicennia marina, of dry and rainy season wood separately for Rhizophora mucronata. The thickness of the pit membranes was measured on transmission electron micrographs while their topochemical nature was also analyzed via cellular UV microspectrophotometry. Pit membranes of R. mucronata were slightly thicker in dry season wood than in rainy season wood, but their spectra showed for both seasons a lignin and a yet unidentified higher wavelength absorbing component. It was suggested to be a derivative of the deposits, regularly filling pit canals. The vestures of A. marina chemically resembled pit membranes rather than cell walls.

Prediction of carbohydrate fractions using equations from the Cornell Net Carbohydrate and Protein System (CNCPS) is a valuable tool to assess the nutritional value of forages. In this paper, these carbohydrate fractions were predicted using data from three sunflower (Helianthus annuus L.) cultivars, fresh or as silage. The CNCPS equations for fractions B2 and C include measurement of ash and protein-free neutral detergent fibre (NDF) as one of their components. However, NDF lacks pectin and other non-starch polysaccharides that are found in the cell wall (CW) matrix, so this work compared the use of a crude CW preparation instead of NDF in the CNCPS equations. There were no differences in the estimates of fractions B1 and C when CW replaced NDF; however, there were differences in fractions A and B2. Some of the CNCPS equations could be simplified when using CW instead of NDF. Notably, lignin could be expressed as a proportion of DM, rather than on the basis of ash and protein-free NDF, when predicting CNCPS fraction C. The CNCPS fraction B1 (starch + pectin) values were lower than pectin determined through wet chemistry. This finding, along with the results obtained by the substitution of CW for NDF in the CNCPS equations, suggests that pectin was not part of fraction B1 but present in fraction A. We suggest that pectin and other non-starch polysaccharides that are dissolved by the neutral detergent solution be allocated to a specific fraction (B2) and that another fraction (B3) be adopted for the digestible cell wall carbohydrates.

In a search for high-quality jute (Corchorus olitorius) fibre using phenotypic marker(s), a single plant from CRIJAF accession OIJ 154 was isolated on the basis of its unique red-tinted pale green stem, which becomes crimson red at maturity, and was given a code name, PPO4. Progenies from this selection bred true with respect to morphological characters. It has a slightly lower height at maturity, but has comparable yield and a higher harvest index when compared to the most popular high-yielding variety JRO 524. In spite of having lower chlorophyll per unit weight of leaf tissue, the photosynthetic rate per unit chlorophyll, the relative growth rate of PPO4 was higher than JRO 524. A composite analysis of quality parameters indicated that the genotype is of higher grade (between TD2 and TD3) with very fine (1.5 tex) fibre of high tensile strength (19.7 g/tex). The lignin content (ca 14%) of the fibre was also less than that of JRO524 (ca 17%) under standard assay conditions. This plant type, with distinct morphological markers, could be utilized in breeding programmes for the genetic improvement of jute.

Foliage construction cost (glucose requirement for formation of a unit foliar biomass, G, kg glu kg−1), chemical composition and morphology were examined along a light gradient across the canopies in five deciduous species, which ranked according to increasing shade-tolerance as Populus tremula <Fraxinus excelsior <Tilia cordata = Corylus avellana <Fagus sylvatica. Light conditions in the canopy were estimated by a hemispheric photographic technique, allowing ranking of sample locations according to long-term light input incident to the sampled leaves (relative irradiance). G and foliage carbon concentration increased with increasing relative irradiance in F. excelsior, T. cordata and C. avellana, but wereindependent of irradiance in F. sylvatica and P. tremula. However, if G of non-structural-carbohydrate-free dry mass was considered, it also increased with increasing relative irradiance in P. tremula. A positive correlation between the concentration of carbon-rich lignin and irradiance, probably a result of the acclimation to greater water stress at higher light, was the major reason for the light-dependence of G. Lignin concentrations were highest in more shade-tolerant species, resulting in greatest carbon concentrations in these species. Since carbon concentration and G are directly linked, the leaves of shade-tolerant species were also more expensive to construct. As the result of these effects, G increased faster with increasing leaf dry mass per area which was mainly determined by relative irradiance, in shade-tolerators. Given that shade-tolerant species had lower leaf dry mass per area at common irradiance and that this saturated at lower relative irradiance than leaf dry mass per area in the intolerant species, it was concluded that enhanced energy requirements for foliage construction might constrain species morphological plasticity and the upper limit of leaf dry mass per area attainable at high light.

Farm residues with high C:N ratios are difficult to use because of their low economic value and excessive volume. Composting is ideal for upgrading such residues, but was not thought possible without co-composting or lowering of the C:N ratio. We developed a low-input method to compost perennial ryegrass straw on-farm by forming windrows and turning them either zero, two, four, or six times throughout the year with a commercial, straddle-type turner. No water beyond normal rainfall and no N other than that contained in the straw was added. The volume of straw was reduced by up to 88% with four or six turns over 20 to 24 weeks. The average internal temperature of straw windrows reached a maximum of 54°C with four turns. The ability to compost these residues will help in the development of sustainable farming systems by allowing recycling of straw waste.