Theoretical and Experimental Plant Physiology最新文献

This essay argues for the importance of an organismic perspective in plant biology and considers some of its implications. These include an increased attention to plant-environment interaction and an emphasis on integrated approaches. Furthermore, this essay contextualizes the increased emphasis on the concept of organism in recent years and places the concept in a longer history. Recent developments in biology and worsening environmental crises have led researchers to study plant responses to changing environments with whole plant approaches that situate plants in their environments, emphasizing the intricate and dynamic interaction between them. This renewed attention to the organism recalls the debates of the early twentieth century, when organicism was one of the three main frameworks in biology (along with vitalism and mechanism). Some scholars see this renewed importance today as a “return” of this earlier period. This essay argues that including insights from plant biology will benefit philosophy of biology research that examines the concept of organism and organicism now and in earlier periods. A comprehensive account of the concept of organism should involve a botanical conception of the organism as well as a zoological one (which is more frequently considered). Although this essay does not aim to present a conceptual analysis, it presents examples of how an organismic perspective can be useful for understanding concepts (such as phenotype, stress, etc.) and research processes (such as experiment set-ups, data processes, etc.) in plant biology. Philosophy of biology investigations that aim at a comprehensive understanding of the concept of organism can benefit greatly from examinations of cases in plant biology, both now and in the past.

Seed reserves are a significant source of essential elements and carbon for seedlings. Trees in the Cerrado vegetation (known as ‘Brazilian savanna’) of Central Brazil are subjected to seasonal drought and grow on dystrophic soils, suggesting that seedlings are dependent on seed reserves for rapid development in the growing season to thrive during the subsequent dry season. However, little is known about the role of cotyledon reserves as a source of carbon and mineral nutrients for recently germinated tree seedlings in the Cerrado. We tested the effects of removing one cotyledon 11 days after germination on growth, biomass distribution, carbon and mineral nutrient stocks of seedlings of Magonia pubescens (Sapindaceae), a large-seeded, anemochorous tree. Seedlings were grown in nutrient-deficient and nutrient-enriched sand for 120 days. For most mineral nutrients (N, P, K, Mg, S, B, Cu and Zn), the stocks in the seeds would be sufficient for seedling development. However, the amounts of Ca, Fe and Mn in the seeds would not be sufficient to meet the needs for plant growth at early stages and must be absorbed from the soil. Fatty acids and soluble sugars were the main carbon reserves in the seeds. The fatty acids were rapidly consumed in the early stages of seedling development. On the other hand, seedlings stored carbon as soluble sugars and starch. Removing one of the cotyledons led to a significant decline in growth, biomass accumulation and mineral nutrient stocks. Fertilization did not reverse the effects of removing one of the cotyledons or increased growth.

Seedlings depend upon seed reserves for the prevision of carbon skeletons for growth and energy production. Post-germinative growth of soybean is therefore marked by the breakdown of carbohydrates, proteins, and lipids and the interconversion of the products of these catabolic processes. Here, we refined a method for ¹³C isotope labelling of heterotrophic soybean seedlings and used it to probe metabolism during this critical phase of plant development. We anticipated that ¹³C labelling would reveal differences in metabolism between the cotyledons (COT) and hypocotyl-root axis (HRA). Feeding with U-¹³C glucose followed by analysis of isotope incorporation indicated uptake and metabolism of this labelled precursor by both COT and HRA. Fractional enrichments were generally greater in the HRA reflecting the catabolism of unlabelled reserves of lipids and proteins in COT. Mass isotopomer distributions confirmed operation of the TCA cycle and glycolysis along with hexose-phosphate cycling in both organs, whilst amino acid synthesis was limited, as expected, given the significant protein reserves. COT differed from HRA in TCA cycle citrate and anapleurotic metabolism. Experiments with ¹³C glycine indicated that glycine decarboxylase and serine hydroxymethyltransferase enzymes may function in heterotrophic tissues as well as in photorespiration. Labelling of the majority of metabolites was constant over time, suggesting that the experimental system could be used for metabolic flux analysis. Overall stable isotope labelling provided significant insight into metabolism of soybean seedlings and could be used to investigate seedling metabolism in other genotypes or species.

Qualitative and quantitative methods were used to demonstrate how plant development stages impact flavonoid C-glycoside and tannin accumulation in Passiflora edulis (Passifloraceae). Distinct parts from juvenile to mature plants were analyzed. Thin-layer chromatography (TLC) and ultra-high performance liquid chromatography (UHPLC) were used to quantify flavonoids as vitexin and tannins as epicatechin, with total flavonoids assessed following the Brazilian Pharmacopoeia method. Ethanolic extracts were tested for urease inhibition. Leaf and fruit shell extracts shared similar flavonoid profiles containing apigenin, chrysin, and luteolin glycosides. Leaves consistently exhibited the highest flavonoid concentration (3.5% dry extract), with 3.6-fold more flavone glycosides than fruit shell extracts. Roots had the highest tannin concentration. Leaf and fruit shell extracts from flowering II plants inhibited urease by 57%. This underscores the significance of flavone C-glycosides as urease inhibitors. The study demonstrates the effective inhibition of ureases by P. edulis fruit shells, highlighting their significant potential for agricultural applications through waste valorization strategies.

CBL-CIPK signaling pathway is a calcium dependent signaling pathway conserved across the plant kingdom. Recent research indicates the central role it plays in growth, development, ion homeostasis and stress management in plants. DELLA proteins are negative regulators of gibberellins and almost ubiquitously influence several aspects of plant physiology. The important role of DELLA proteins in green revolution was discovered and very recently they are found to influence several aspects of root growth and root-microbe interactions. Thus, understanding the genetic network involving CBL-CIPK signaling pathway and DELLA proteins in plant roots can identify targets for biotechnological innovations. This may propel generation of transgenic lines with robust root system capable of efficient water and ion absorption with higher degree of selectivity and regulation. Plant improvement through breeding and genetic modifications have largely focused on the above-ground parts and there is a vast space for similar improvement concerning roots. CBL-CIPK and DELLA can serve as excellent genetic engineering candidates for climate smart agriculture, alleviation of hidden hunger, phytoremediation of heavy metals and environmental sustainability.

Bertholletia excelsa Bonpl. is widely planted in the Amazon and information about thinning effects is poorly documented. Here, we investigate thinning effects on the ecophysiology of B. excelsa plantations. The thinning trial was set up as a randomized complete block design (RCBD) with two treatments (unthinned and thinned to 50% basal area removal). The canopy openness of plots thinned was two times higher than the unthinned treatment (control). B. excelsa under thinning growed three times in relation to trees of control. One week after thinning, we observed increase of 25% photosynthesis (P_N), 100% respiration (R_d), 35% stomatal conductance (g_s), and 25% transpiration (E). After thinning, we verified reduction of the maximum photochemical efficiency of photosystem II (F_V/F_M), with subsequent recovery. At the end of 5 months after thinning, the trees on thinned plots achieved values of leaf mass per area (LMA), nitrogen (N_a), phosphorus (P_a), and potassium (K_a) about 27% higher than trees of unthinned plots. Thinning did not affect the midday leaf water potential (Ψw). Thinning increased the growth of B. excelsa influenced by photosynthetic performance and regulated by the g_s, LMA, leaf N_a, and P_a concentrations. Our findings demonstrated that thinning can be recommended for timber production under the dense planting of Brazil nut trees cultivated in degraded Amazonian areas.

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Electrical impedance spectroscopy (EIS) is a technique used for detection of leaf moisture content (LMC). Generally, EIS is inconvenient and destructive. This paper proposed a non-destructive method for predicting LMC of Epipremnum aureum based on the impedance spectrocopy with the combination of ECG gel and needle electrodes. An effective equivalent circuit model for the corresponding gel contact method was established. The LMC model of E. aureum was obtained based on equivalent circuit parameters. The results demonstrated that there were two arcs in the Cole–Cole plots of the leaves measured by the gel contact method. The arc in the high frequency region reflected the impedance characteristics of the leaf, while the arc in the low frequency region was relevant to the impedance of the ECG gel and the polarization impedance caused by the contact with leaves. The gel contact model was suitable for fitting the leaf impedance spectroscopy measured by the gel contact method. The R_R² and R_X² for each R and X were both greater than 0.999. Meanwhile, the LMC prediction model based on extracellular resistance showed the best performance, with the coefficient of determination (R²) and root-mean-square error (RMSE) for prediction being 0.803, 0.0580, respectively.

Soil carbon sequestration is a vital ecosystem function that mitigates climate change by absorbing atmospheric carbon dioxide (CO₂). Root characteristics such as depth, diameter, length, and branching pattern affect soil carbon dynamics through root-soil interactions and organic matter breakdown. Here we review field surveys, laboratory analysis, and mathematical modeling to understand how root structures affect soil carbon storage. Further, certain root features increase soil carbon sequestration, suggesting that selective breeding and genetic engineering of plants could maximize this ecological benefit. However, more research is needed to understand the complex interactions between roots, soil biota, and soil organic matter under changing environmental conditions. In addition, the benefit of climate change mitigation methods and soil carbon models from the inclusion of root architecture was reviewed. Studies in the realm of root-soil interactions encompass a variety of academic fields, including agronomy, ecology, soil science, and plant physiology. Insights into how roots interact with their soil environment and the effects of these interactions on plant health, agricultural productivity, and environmental sustainability have been gained through this research.