Cereal protoplast recalcitrance

Summary Cereal leaf protoplasts are extremely difficult to culture (recalcitrant) in vitro. There have been few reports of division and the protoplasts typically exhibit excessive enlargement and vacuolization with reduced cell wall deposition. Inasmuch as leaf base explants are capable of callus formation in vitro, protoplasts derived from this tissue must have lost the ability to divide as a consequence of changes induced by the wall-digestion process. We review evidence suggesting that the inhibition of mitosis in these protoplasts is a consequence of a cascade of events initiated at the plasma membrane. The enzyme treatment necessary for wall removal triggers membrane depolarization and other changes that can lead to the initiation of lipid peroxidation and oxidative stress. Mitotically inactive cereal leaf protoplasts are unable to mount a protective response to these degradative processes. Consequently, the resulting membrane perturbations and permeabilization give rise to secondary effects on the cytoskeleton and the cell wall. These effects include reduced or absent microtubules as well as reduced and uneven wall deposition. Such abnormalities are observed in cereal leaf protoplasts and are sufficient to account for recalcitrance because the occurrence of mitosis is strongly dependent on a normal cell wall and cytoskeleton. This paper is NRCC number 32475.     

A mathematical model with young predation

We generalise the model of [21] in which the author considered a predator-prey system with predators eating only the young ones (or eggs) of the prey species. The prime assumption of the present paper is that the birth rate (per unit individual per unit time) of predators depends not only on the current prey egg-level but also on all previous prey egg-levels. It is seen that under this assumption an otherwise stable system may be stable as well as unstable leading to the conclusion that young predation with time delay is less stable than without it. Finally for the model of [21] we prove a result which shows that large predation rates help in the co-existence of both predator and prey species.     

Termites Improve the Horizontal Movement of Carbonized Particles: A Step towards Sustainable Utilization of Biochar

Soil amendments containing carbonized materials increase the soil carbon reservoir, influence plant productivity, and, ultimately, help to clean the environment. There is data on the effect of such additions on soil physicochemical properties or plant growth, but few studies have focused on how these carbonized materials are distributed by termite species in the soil ecosystem. It is the first comprehensive study of the transportation of biochar (BC) by termite species under tropical environmental conditions in Pakistan. The present study was carried out to test the hypothesis that if termite species I) were involved in the distribution of biochar particles II) if yes, then how far these particles were transported during the study period (10 days) and III) check their preference between the enriched BC (EBC) and non-enriched BC. BC was enriched with the cattle slurry after its pyrolysis in the study. The results showed that EBC particles were significantly more widely distributed than non-enriched BC particles, but both types of BC were transported more than 4 cm (ring 4) within 10 days (at the end of the experiment). The current study also revealed that EBC was easily attached to the setae, cuticle, and legs of termites, implying that it could potentially be transported over a greater distance. Furthermore, transportation of EBC over larger distances indicated a potential preference of termite species between the EBC and BC particles. During the study, however, the preference among the termite species was also observed. Under the prevailing study conditions, the Coptotermes heimi and Heteroterme indicola species transported the EBC further than Microtermes obesi and Odontotermes obesus. These findings revealed that transportation preferences were observed among the four termite species. In conclusion, the current study found that termites were involved in the distribution of BC particles, with a preference for EBC and that these have the potential to transport BC particles more than 4 cm within 10 days. Furthermore, two species Coptotermes heimi and Heteroterme indicola may be more suitable candidates for EBC transpiration in Pakistani soils. It was necessary to conduct additional research into the effect of temperature on the transportation process.     

Salinity Stress in Wheat: Effects,Mechanisms and Management Strategies

Salinity stress is a major threat to global food production and its intensity is continuously increasing because of anthropogenic activities. Wheat is a staple food and a source of carbohydrates and calories for the majority of people across the globe. However, wheat productivity is adversely affected by salt stress, which is associated with a reduction in germination, growth, altered reproductive behavior and enzymatic activity, disrupted photosynthesis, hormonal imbalance, oxidative stress, and yield reductions. Thus, a better understanding of wheat (plant) behavior to salinity stress has essential implications to devise counter and alleviation measures to cope with salt stress. Different approaches including the selection of suitable cultivars, conventional breeding, and molecular techniques can be used for facing salt stress tolerance. However, these techniques are tedious, costly, and labor-intensive. Management practices are still helpful to improve the wheat performance under salinity stress. Use of arbuscular mycorrhizal fungi, plant growth-promoting rhizobacteria, and exogenous application of phytohormones, seed priming, and nutrient management are important tools to improve wheat performance under salinity stress. In this paper, we discussed the effect of salinity stress on the wheat crop, possible mechanisms to deal with salinity stress, and management options to improve wheat performance under salinity conditions.     

Exploration of Genetic Pattern of Phenological Traits in Wheat (<i>Triticum aestivum</i> L.) under Drought Stress

Drought is the major detrimental environmental factor for wheat (Triticum aestivum L.) production. The exploration of genetic patterns underlying drought tolerance is of great significance. Here we report the gene actions controlling the phenological traits using the line × tester model studying 27 crosses and 12 parents under normal irrigation and drought conditions. The results interpreted via multiple analysis (mean performance, correlations, principal component, genetic analysis, heterotic and heterobeltiotic potential) disclosed highly significant differences among germplasm. The phenological waxiness traits (glume, boom, and sheath) were strongly interlinked. Flag leaf area exhibits a positive association with peduncle and spike length under drought. The growing degree days (heat-units) greatly influence spikelets and grains per spike, however, the grain yield/plant was significantly reduced (17.44 g to 13.25 g) under drought. The principal components based on eigenvalue indicated significant PCs (first-seven) accounted for 79.9% and 73.9% of total variability under normal irrigation and drought, respectively. The investigated yield traits showed complex genetic behaviour. The genetic advance confronted a moderate to high heritability for spikelets/spike and grain yield/plant. The traits conditioned by dominant genetic effects in normal irrigation were inversely controlled by additive genetic effects under drought and vice versa. The magnitude of dominance effects for phenological and yield traits, i.e., leaf twist, auricle hairiness, grain yield/plant, spikelets, and grains/spike suggests that selection by the pedigree method is appropriate for improving these traits under normal irrigation conditions and could serve as an indirect selection index for improving yield-oriented traits in wheat populations for drought tolerance. However, the phenotypic selection could be more than effective for traits conditioned by additive genetic effects under drought. We suggest five significant cross combinations based on heterotic and heterobeltiotic potential of wheat genotypes for improved yield and enhanced biological production of wheat in advanced generations under drought.     

Effect of exogenous abscisic acid (ABA) on the morphology,phytohormones, and related gene expression of developing lateral roots in ‘Qingzhen 1’ apple plants

Plant Cell, Tissue and Organ Culture (PCTOC) - Lateral roots (LRs) are critical for plant stress tolerance and productivity. Understanding how hormones and genes interact in a fluctuating...     

Cowpea induced physicochemical and biological rhizosphere changes in hydrocarbon contaminated soil

Plant and Soil - To understand the influence of cowpea on its rhizosphere physicochemical and biological conditions. Pristine soil samples were contaminated with Bonny-Light crude oil and viable...     

How Physical Disturbance and Nitrogen Addition Affect the Soil Carbon Decomposition?

The decomposition of soil organic carbon (SOC) plays a critical role in regulating atmospheric CO₂ concentrations and climate dynamics. However, the mechanisms and factors controlling SOC decomposition are still not fully understood. Here, we conducted a 60 days incubation experiment to test the effects of physical disturbance and nitrogen (N) addition on SOC decomposition. N addition increased the concentration of NO₃^- by 51% in the soil, but had little effect on the concentration of NH₄⁺. N addition inhibited SOC decomposition, but such an effect differed between disturbed and undisturbed soils. In disturbed and undisturbed soils, application of N decreased SOC decomposition by 37% and 15%, respectively. One possible explanation is that extra N input suppressed microbial N mining and/or increased the stability of soil organic matter by promoting the formation of soil aggregates and incorporating part of the inorganic N into organic matter, and consequently decreased microbial mineralization of soil organic matter. Physical disturbance intensified the inhibition of N on SOC decomposition, likely because physical disturbance allowed the added N to be better exposed to soil microbes and consequently increased the availability of added N. We conclude that physical disturbance and N play important roles in modulating the stability of SOC.     

Spatial patterns and determinants of Moraceae richness in China

Understanding large-scale patterns of biodiversity and their drivers remains central in ecology. Many hypotheses have been proposed, including hydrothermal dynamic hypothesis, tropical niche conservatism hypothesis, Janzen’s hypothesis and a combination model containing energy, water, seasonality and habitat heterogeneity. Yet, their relative contributions to groups with different lifeforms and range sizes remain controversial, which have limited our ability to understand the general mechanisms underlying species richness patterns. Here we evaluated how lifeforms and species range sizes influenced the relative contributions of these three hypotheses to species richness patterns of a tropical family Moraceae. The distribution data of Moraceae species at a spatial resolution of 50km ×50 km and their lifeforms (i.e. shrubs, small trees and large trees) were compiled. The species richness patterns were estimated for the entire family, different life forms and species with different range sizes separately. The effects of environmental variables on species richness were analyzed, and relative contributions of different hypotheses were evaluated across life forms and species range size groups. The species richness patterns were consistent across different species groups and the species richness was the highest in Sichuan, Guangzhou and Hainan provinces, making these provinces the hotspots of this family. Climate seasonality is the primary factor in determining richness variation of Moraceae. The best combination model gave the largest explanatory power for Moraceae species richness across each group of range size and life forms followed by the hydrothermal dynamic hypothesis, Janzen’s hypothesis and tropical niche conservatism hypothesis. All these models has a large shared effects but a low independent effect (< 5%), except rare species. These findings suggest unique patterns and mechanisms underlying rare species richness and provide a theoretical basis for protection of the Moraceae species in China.