root systems
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Little is known of how the deep root systems of perennial crops contribute to deeper and better resource use when intercropped with annuals in arable fields. Therefore, we aimed at measuring the capacity of perennial deep roots, alfalfa (Medicago sativa L.) and curly dock (Rumex crispus L.) to access the nutrient source located under the neighboring annuals at 1.0 and 2.5 m of soil depth. Alfalfa and curly dock were able to access the tracer-labelled source placed at a distance under the annual crop strips. As a result, the reliance on deeper soil layer for nutrient uptake under intercroppings became greater compared with sole-croppings. Combination of an annual cereal (winter rye) and a perennial legume (alfalfa) with contrasting root systems exhibited higher resource complementarity compared with intercroppings having similar root systems or absence of legumes. Our results demonstrated that the deep-rooted perennials when intercropped with annuals can induce vertical niche complementarity, especially at deeper soil layers. This was assumed to be due to the vertically stratified root activity between the crop components, however, the magnitude of the effects depended on choice of crop combinations, and on types of tracers. Future studies should include estimates such as relative yield total and land equivalent ratio to quantitatively determine the effects of resource acquisition under annual-perennial intercropping in arable fields.

AbstractWe develop an algorithm for computing the cohomology of complements of toric arrangements. In the case a finite group $$\Gamma $$ Γ is acting on the arrangement, the algorithm determines the cohomology groups as representations of $$\Gamma $$ Γ . As an important application, we determine the cohomology groups of the complements of the toric arrangements associated with root systems of exceptional type as representations of the corresponding Weyl groups.

AbstractOld forests containing ancient trees are essential ecosystems for life on earth. Mechanisms that happen both deep in the root systems and in the highest canopies ensure the viability of our planet. Old forests fix large quantities of atmospheric CO2, produce oxygen, create micro-climates and irreplaceable habitats, in sharp contrast to young forests and monoculture forests. The current intense logging activities induce rapid, adverse effects on our ecosystems and climate. Here we review large old trees with a focus on ecosystem preservation, climate issues, and therapeutic potential. We found that old forests continue to sequester carbon and fix nitrogen. Old trees control below-ground conditions that are essential for tree regeneration. Old forests create micro-climates that slow global warming and are irreplaceable habitats for many endangered species. Old trees produce phytochemicals with many biomedical properties. Old trees also host particular fungi with untapped medicinal potential, including the Agarikon, Fomitopsis officinalis, which is currently being tested against the coronavirus disease 2019 (COVID-19). Large old trees are an important part of our combined cultural heritage, providing people with aesthetic, symbolic, religious, and historical cues. Bringing their numerous environmental, oceanic, ecological, therapeutic, and socio-cultural benefits to the fore, and learning to appreciate old trees in a holistic manner could contribute to halting the worldwide decline of old-growth forests.

AbstractKajihara obtained in 2004 a remarkable transformation formula connecting multiple basic hypergeometric series associated with A-type root systems of different ranks. By specialisations of his formula, we deduce kernel identities for deformed Macdonald–Ruijsenaars (MR) and Noumi–Sano (NS) operators. The deformed MR operators were introduced by Sergeev and Veselov in the first order case and by Feigin and Silantyev in the higher order cases. As applications of our kernel identities, we prove that all of these operators pairwise commute and are simultaneously diagonalised by the super-Macdonald polynomials. We also provide an explicit description of the algebra generated by the deformed MR and/or NS operators by a Harish-Chandra type isomorphism and show that the deformed MR (NS) operators can be viewed as restrictions of inverse limits of ordinary MR (NS) operators.

The present paper is devoted to twisted foldings of root systems that generalize the involutive foldings corresponding to automorphisms of Dynkin diagrams. A motivating example is Lusztig’s projection of the root system of type E 8 E_8 onto the subring of icosians of the quaternion algebra, which gives the root system of type H 4 H_4 . By using moment graph techniques for any such folding, a map at the equivariant cohomology level is constructed. It is shown that this map commutes with characteristic classes and Borel maps. Restrictions of this map to the usual cohomology of projective homogeneous varieties, to group cohomology and to their virtual analogues for finite reflection groups are also introduced and studied.

Root-system architecture is vital for improving soybean (Glycine max L.) growth and nutrient uptake. We characterised root-system architecture and shoot traits of 30 soybean genotypes in a semi-hydroponic system 35 days after sowing (DAS) and validated eight genotypes with contrasting root-system architecture in 1.5 m-deep rhizoboxes at the flowering stage. Among them, two genotypes were selected for evaluation through to maturity. Abundant variation (coefficient of variation values ≥ 0.25) was observed in 11 of 13 measured roots and shoot traits during the early growth stage. After late growth stages, strong positive correlations were found between root traits and shoot traits, except for specific root length and diameter. Seed yield and yield traits at final harvest significantly differed between two contrasting soybean genotypes. The large-rooted genotype had a higher harvest index than the small-rooted genotype. Soybean genotypes with larger root systems had a long time to flowering than those with smaller root systems. Genotypes with large-root systems had 106% more leaf area, and 245% more shoot dry weight than those with small systems, presumably due to high canopy photosynthesis to supply the demand for carbon assimilates to roots. Total root length, and root: shoot ratio-traits data collected in the rhizobox study, strongly correlated with the same traits in the semi-hydroponic phenotyping system. We found genetic variation and phenotypic plasticity in other root and shoot traits such as taproot depth, root dry weight, specific root length, and average root diameter among the tested genotypes. Phenology, particularly time to flowering, was associated with root system size. Some root and shoot traits in the semi-hydroponic phenotyping system at the seedling stage produced similar rankings at the later phenological (flowering) stage when grown in the soil-filled rhizoboxes. The soybean genotypes characterised by vastly different root traits could be used for further glasshouse and field studies to improve adaptation to drought and other specific environments.

An increase in the frequency and severity of droughts associated with global warming has resulted in deleterious impacts on forest productivity in Southwest China. Despite attempts to explore the response of vegetation to drought, less is known about forest’s resilience in response to drought in Southwest China. Here, the reduced resilience of the forest was found based on remotely sensed optical and microwave vegetation products. The spatial distribution and temporal variation of resilience-reduced forest were assessed using the standardized precipitation evapotranspiration index (SPEI) and vegetation optical depth (VOD). Our findings showed that 40–50% of the forest appeared to have abnormally low resilience approximately 6 months after the severe drought. The spatial distributions of abnormally low resilience had a good agreement with the regions affected by the 2009–2011 drought events. In particular, our results indicated that areas of afforestation were more susceptible to drought than natural forest, maybe due to the different water uptake strategy of the diverse root systems. Our findings highlight the vulnerability of afforestation areas to climate change, and recommend giving more attention to soil water availability.

Abstract The research presents the results of an experiment on propagation of core rot-resistant aspen clones (Populus tremula L.) of diploid and triploid genotypes using microclonal propagation method and their introduction into forestry production in the Republic of Tatarstan. The expediency of using this method in the conditions of the Republic for obtaining healthy aspen planting material is proved, and the prospects of reproduction of clone No.35 with a triploid genotype are shown. The reliable difference of test tube regenerating plants of triploid forms in the height of the shoot and in the development of root systems is proved

The article is devoted to the study of the effect of biofertilizers on the number of different groups of soil microarthropods of chernozem of ordinary agrocenosis of perennial grasses in the condi-tions of the Lower Don. Most groups of mites and collembolus on the agrocenosis of perennial grasses, being saprophages by the nature of nutrition, undoubtedly play an important role in the circulation of substances, indirectly affecting the productivity of the agrocenosis. It was found that when applying the biofertilizer "Vesna", the number of all groups of microarthropods at the exper-imental site exceeded the control indicators by 1.5 times. All groups of ticks showed a large num-ber, gamase and shell ticks prevailed. The number of leg-tails was less than the number of ticks in the experimental area, but it turned out to be higher than the number of leg-tails in the control ar-ea. The vertical distribution of microarthropods in the horizon of 0-20 cm of the chernozem of the ordinary agrocenosis of perennial grasses was characterized by an uneven distribution: basically all groups of ticks and longtails are concentrated in the horizon of 0-10 cm, which is determined by the gradient of hydrothermal conditions and the distribution of root systems of plants of agro-cenosis.