Plant Body Research Articles

Updating the Knowledge on the Secretory Machinery of Hops (Humulus lupulus L., Cannabaceae).

Cannabaceae species garner attention in plant research due to their diverse secretory structures and pharmacological potential associated with the production of secondary metabolites. This study aims to update our understanding of the secretory system in Hops (Humulus lupulus L.), an economically important species especially known for its usage in beer production. For that, stems, leaves, roots, and inflorescences were collected and processed for external morphology, anatomical, histochemical, ultrastructural and cytochemical analyses of the secretory sites. Our findings reveal three types of secretory structures comprising the secretory machinery of Hops: laticifer, phenolic idioblasts and glandular trichomes. The laticifer system is articulated, anastomosing and unbranched, traversing all plant organs, except the roots. Phenolic idioblasts are widely dispersed throughout the leaves, roots and floral parts of the species. Glandular trichomes appear as two distinct morphological types: capitate (spherical head) and peltate (radial head) and are found mainly in foliar and floral parts. The often-mixed chemical composition in the secretory sites serves to shield the plant from excessive UVB radiation, elevated temperatures, and damage inflicted by herbivorous animals or pathogenic microorganisms. Besides the exudate from peltate glandular trichomes (lupulin glands), latex and idioblast content are also likely contributors to the pharmacological properties of different Hop varieties, given their extensive presence in the plant body.

Impact of Cadmium-Induced Stress on Physiological Traits with Induced Osmolyte and Catalase-Mediated Antioxidative Defense in Rice (Oryza sativa L.)

Cadmium is one of the most carcinogenic and hazardous heavy metals on the earth for causes many serious diseases and disorders in the plant body. The presence of Cd in the soil is equally harmful to the production of rice crops and human beings. A pot experiment was conducted to analyze the consequences of cadmium-induced stress on the antioxidative defense system in rice plants. The assessment of antioxidative defense mechanism based on the cadmium-induced stress in the range of 100 to 300 ppm while the parameters, Chlorophyll Content Index (SPAD), nitrogen (%), relative water content (%), membrane stability index (%), proline content (μg.g-1), and catalase activity (nm H2O2 mg-1.min-1) were used. The highest reduction in the Chlorophyll Content Index (CCI), nitrogen (%), RWC (%), and MSI (%) was recorded at the highest concentrations of Cd Cl2 (300 ppm). However, at the same time, an increase in proline content (μg.g-1) and catalase activity (nm H2O2 mg-1.min-1) were also detected at all the intervals of the study. The activity of CCI, amino acid, and enzyme were presented in % increase/decrease over the control of Cd-induced stress in rice plants. The reduction (%) in CCI (SPAD) and RWC (%) was recorded maximum at 75 Days after transplanting (DAT), while nitrogen (%) and MSI (%) were recorded at 50 DAT. However, the increase (%) in proline and Catalase activity was maximum at 75 and 50 DAT.

Polarity establishment in the plant zygote at a glance.

The complex structures of multicellular organisms originate from a unicellular zygote. In most angiosperms, including Arabidopsis thaliana, the zygote is distinctly polar and divides asymmetrically to produce an apical cell, which generates the aboveground part of the plant body, and a basal cell, which generates the root tip and extraembryonic suspensor. Thus, zygote polarity is pivotal for establishing the apical-basal axis running from the shoot apex to the root tip of the plant body. The molecular mechanisms and spatiotemporal dynamics behind zygote polarization remain elusive. However, advances in live-cell imaging of plant zygotes have recently made significant insights possible. In this Cell Science at a Glance article and the accompanying poster, we summarize our understanding of the early steps in apical-basal axis formation in Arabidopsis, with a focus on de novo transcriptional activation after fertilization and the intracellular dynamics leading to the first asymmetric division of the zygote.

COMPARATIVE ANALYSIS OF THE ELEMENTAL COMPOSITION OF ORGANS OF PROMISING SPECIES OF THE GENUS IRIS L. (IRIDACEAE)

Plants of the genus Iris L. are promising medicinal raw materials with significant biological and pharmacological activity. The quality of plant raw materials depends on the accumulation and distribution of potentially hazardous chemical elements in the plant body. The aim of this work was a comparative study of the accumulation and transfer of elements through the organs of plants of the genus Iris L. (Iridaceae). The content of As, Cd, Cr, Cu, Mn, Ni, and Pb in different parts of I. orientalis, I. pseudacorus, I. sibirica and I. spuria plants was analyzed by atomic absorption. It has been established that in the absence of soil pollution, irises accumulate arsenic in concentrations exceeding the maximum allowable. The accumulation of chromium in the raw material was also above the maximum allowable concentration for a number of study options. The efficiency of element transfer from the soil to the root system varied significantly (bioaccumulation factor 0.2–4.4). Iris rhizomes absorbed nickel most actively. The assimilation ability of the roots is also clearly expressed in relation to Pb, As, Cr, Cu, Mn. Depending on the element, accumulation in leaves is species-specific. The carrying capacity of the peduncle is most pronounced in I. sibirica, the barrier capacity is most pronounced in I. orientalis. Various types of translocation of elements in organs were revealed: acropetal, uniform, basipetal. All studied species are characterized by acropetal distribution of Pb (translocation factor >1) and uniform distribution of Mn. The location of Cd may vary depending on the species. Cu is concentrated in the roots (I. orientalis, I. sibirica, I. spuria) or evenly distributed (I. pseudacorus). The revealed patterns of accumulation and distribution of elements in the organs of plants of the genus Iris make it possible to carry out a prognostic assessment of the quality of raw materials to obtain safe products.

Stem Cells and Differentiation in Vascular Tissues.

Plant vascular tissues are crucial for the long-distance transport of water, nutrients, and a multitude of signal molecules throughout the plant body and, therefore, central to plant growth and development. The intricate development of vascular tissues is orchestrated by unique populations of dedicated stem cells integrating endogenous as well as environmental cues. This review summarizes our current understanding of vascular-related stem cell biology and of vascular tissue differentiation. We present an overview of the molecular and cellular mechanisms governing the maintenance and fate determination of vascular stem cells and highlight the interplay between intrinsic and external cues. In this context, we emphasize the role of transcription factors, hormonal signaling, and epigenetic modifications. We also discuss emerging technologies and the large repertoire of cell types associated with vascular tissues, which have the potential to provide unprecedented insights into cellular specialization and anatomical adaptations to distinct ecological niches.

Pectin-Coated Iron-Based Metal-Organic Framework Nanoparticles for Enhanced Foliar Adhesion and Targeted Delivery of Fungicides.

Conventional agrochemicals are underutilized due to their large particle sizes, poor foliar retention rates, and difficult translocation in plants, and the development of functional nanodelivery carriers with high adhesion to the plant body surface and efficient uptake and translocation in plants remains challenging. In this study, a nanodelivery system based on a pectin-encapsulated iron-based MOF (TF@Fe-MOF-PT NPs) was constructed to enhance the utilization of thifluzamide (TF) in rice plants by taking advantage of the pectin affinity for plant cell walls. The prepared TF@Fe-MOF-PT NPs exhibited an average particle size of 126.55 nm, a loading capacity of 27.41%, and excellent dual-stimulus responses to reactive oxygen species and pectinase. Foliar washing experiments showed that the TF@Fe-MOF-PT NPs were efficiently adhered to the surfaces of rice leaves and stems. Confocal laser scanning microscopy showed that fluorescently labeled TF@Fe-MOF-PT NPs were bidirectionally delivered through vascular bundles in rice plants. The in vitro bactericidal activity of the TF@Fe-MOF-PT NPs showed better inhibitory activity than that of a TF suspension (TF SC), with an EC50 of 0.021 mg/L. A greenhouse test showed that the TF@Fe-MOF-PT NPs were more effective than TF SC at 7 and 14 d, with control effects of 85.88 and 78.59%, respectively. It also reduced the inhibition of seed stem length and root length by TF SC and promoted seedling growth. These results demonstrated that TF@Fe-MOF-PT NPs can be used as a pesticide nanodelivery system for efficient delivery and intelligent release in plants and applied for sustainable control of pests and diseases.

Root physiological and soil microbial mechanisms underlying responses to nitrogen deficiency and compensation in Indica and Japonica rice.

Compensatory effects are common biological phenomena in nature. In this study, we investigated the changes in root nitrogen uptake, root morphological and physiological responses, and changes in the rhizosphere soil microbial communities of indica and japonica rice during a nitrogen deficiency-sensitive period and an effective compensation period with double the nitrogen supply. We conducted a bucket experiment using Suxiu 867 (a japonica rice variety) and Yangxian You 918 (an indica rice variety). Treatments included CK (constant distribution of nitrogen fertilizer at each growth stage, represented by CK867 and CK918) and NDC (nitrogen deficiency in the tillering stage, double nitrogen application in the ear differentiation stage to compensate, represented by NDC867 and NDC918) variations. Both varieties presented the highest δ15N and 15N abundances and Ndff (refers to the proportion of nitrogen in a plant's body that comes directly from the fertilizer applied.) in rice under the NDC treatment. Metagenomic sequencing of rhizospheric soil showed that the dominant bacterial groups at the phylum level among each treatment were Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteria, Gemmatimonadetes, and Nitrospirae. The rhizosphere of indica rice was more enriched with the microbial communities involved in nitrogen metabolism, which contributed to higher nitrogen utilization efficiency. A correlation-based network was constructed and provides insights into the formation of nitrogen deficiency compensation effects and contributes to the enhancement of nitrogen uptake and utilization efficiency in rice production.

Heavy metal accumulation and health risk assessment in S. alterniflora Loisel. and native plant Suaeda salsa (L.) Pall. in Dongtai Tiaozini wetland

Coastal wetlands play an irreplaceable role in the global ecosystem, and both human activities and natural factors may lead to the contamination of Tiaozini coastal wetland with heavy metals. The study was conducted to determine the contents of eight heavy metals, Hg, Cd, Cr, As, Pb, Cu, Ni, and Zn, in the above-ground and below-ground parts of the plants and in the rhizosphere sediment, using the invasive species S. alterniflora and the native plant S. glauca, calculating the geoaccumulation index (Igeo), bioaccumulation factor, transfer factor, total target risk quotient (TTHQ), and carcinogenicity risk (CR), to analyze the transfer characteristics and potential health risks to human beings of the heavy metals in plants. This study aims to investigate the enrichment characteristics of the dominant plant, S. alterniflora Loisel. (S. alterniflora) and Suaeda salsa (L.) Pall. (S. glauca). Regarding heavy metals, eight common heavy metal elements were selected, including Hg, Cd, Cr, As, Pb, Cu, Ni, and Zn, and examined their content in surface sediments and different parts of the two plants. The transfer characteristics of heavy metals in the plant body and their potential health risks to humans were also analyzed. These findings suggest that both plants accumulate higher concentrations of heavy metals in their below-ground parts. Cr, Cu, and Zn had the highest average concentrations in both plants. Geoaccumulation index (Igeo) indicated that the Tiaozini Wetland is not yet contaminated. S. alterniflora had transfer factors less than 1 for all heavy metals, while S. glauca had transfer factors greater than 1. Both plants had a certain purifying effect on heavy metal pollution in wetlands, including Cr, Cd, Cu, and Zn. However, Cr and As in the below-ground part of S. alterniflora and Cr in the above-ground part of S. glauca had a target hazard quotient (THQ) greater than 1, indicating a potential health risk to humans, but the carcinogenic risk is low. For other heavy metals, THQ was less than 1, indicating no health risk. The total target hazard quotient (TTHQ) of different parts of both plants was greater than 1, which must be taken into account when considering their suitability as edible resources.

Physiological adaptation to irradiance in duckweeds is species and accession specific and depends on light habitat niche.

Duckweeds span 36 species of free-floating aquatic organisms with body sizes ranging from 2 mm to 10 mm, where each plant body plan is reduced to a largely leaf-like structure. As an emerging crop, their fast growth rates offer potential for cultivation in closed systems. We describe a novel UK collection derived from low light (dLL) or high light (dHL) habitats, profiled for growth, photosynthesis, and photoprotection (non-photochemical quenching, NPQ) responses. Twenty-three accessions of three Lemna species and one Spirodela polyrhiza were grown under relatively low light (LL: 100 μmol m-2 s-1) and high light (HL: 350 μmol m-2 s-1) intensities. We observed broad within- and between-species level variation in photosynthesis acclimation. Duckweeds grown under HL exhibited a lower growth rate, biomass, chlorophyll, and quantum yield of photosynthesis. In HL compared with LL, carotenoid de-epoxidation state and NPQ were higher, whilst PSII efficiency (φPSII) and Chl a:b ratios were unchanged. The dLL plants showed relatively stronger acclimation to HL compared with dHL plants, especially Lemna japonica accessions. These achieved faster growth in HL with concurrent higher carotenoid levels and NPQ, and less degradation of chlorophyll. We conclude that these data support local adaptation to the light environment in duckweed affecting acclimation in controlled conditions.

Suspension culture of stem cells established of Calendula officinalis L.

Plant stem cell cultures have so far been established in only a few plant species using cambial meristematic cells. The presence of stem cells or stem cell-like cells in other organs and tissues of the plant body, as well as the possibility of de novo generation of meristematic cells from differentiated cells, allow to consider the establishment of stem cell cultures in a broader range of species. This study aimed to establish a stem cell culture of the medicinal plant Calendula officinalis L. Callus tissues were induced from leaf and root explants, and already at this stage, stem and dedifferentiated cells could be identified. The cell suspension cultures established both from the root- and leaf-derived calli contained a high proportion of stem cells (92–93% and 72–73%, respectively). The most effective combination of growth regulators for the development of stem cells in calli as well as cell cultures was 1.0 mg/L 2,4-D and 0.5 mg/L BAP. The highest amount of stem cells (5.60–5.72 × 105) was in cell suspension derived from the roots. An effective protocol for the establishment of marigold stem cell suspension culture was developed. The ratio of root-derived stem cells against dedifferentiated cells exceeded 90%.

A novel isophorone-based fluorescent probe for recognizing Al3+ and its bioimaging in plants.

Aluminium ions (Al3+) are widely present in industries and daily life and are closely related to human health and environmental protection. Therefore, it is crucial to detect their concentration. In this paper, a convenient and reliable small molecule fluorescent probe based on a dicyanoisophorone Schiff base and 2-pyridinecarbohydrazide has been developed. The probe is capable of selectively detecting Al3+ with the advantages of near-infrared emission (maximum emission wavelength of 625 nm), good selectivity, high sensitivity (detection limit of 2.18 × 10-7 M) and fast response time (15 s). It has good potential for rapid detection and visual tracking of Al3+ in aqueous solutions and plant bodies.

Discontinuous Translocation of a Luciferase Protein beyond Graft Junction in Tobacco.

Transgrafting, a grafting technique that uses both genetically modified (GM) and non-GM plants, is a novel plant breeding technology that can be used to improve the efficiency of crop cultivation without introducing foreign genes into the edible parts of non-GM plants. This technique can facilitate the acquisition of disease resistance and/or increased yield. However, the translocation of low-molecular-weight compounds, ribonucleic acid (RNA), and proteins through graft junctions raises a potential safety risk for food crops. Here, we used a transgenic tobacco plant expressing a firefly luciferase gene (LUC) to examine the translocation of the LUC protein beyond the graft junction in grafted plants. We observed the bi-directional translocation of LUC proteins in transgrafted tobacco plants, i.e., from the rootstock to scion and vice versa. Transcriptomic analysis revealed that transcripts of the LUC gene were undetectable in non-GM plant bodies, indicating that the LUC protein itself was translocated. Moreover, the movement of the LUC protein is an episodic (i.e., non-continuous) event, since non-GM samples showing high LUC activity were flanked by non-GM samples showing no apparent LUC activity. Translocation from the GM to non-GM part depends on the characteristics of GM plant bodies; here, the enhanced translocation of the LUC protein into the non-GM scion was observed when LUC-expressing rootstocks with hairy roots were used. Moreover, the quantity of translocated LUC protein was far below the level that is generally required to induce an allergenic response. Finally, since the LUC protein levels of plants used for transgrafting are moderate and the LUC protein itself is relatively unstable, further investigation is necessary regarding whether the newly expressed protein in GM plants is highly stable, easily translocated, and/or highly expressed.

Dynamic evolution of MADS-box genes in extant ferns via large-scale phylogenomic analysis.

Several studies of MADS-box transcription factors in flowering plants have been conducted, and these studies have indicated that they have conserved functions in floral organ development; MIKC-type MADS-box genes has been proved to be expanded in ferns, however, few systematic studies of these transcription factors have been conducted in non-seed plants. Although ferns and seed plants are sister groups, they exhibit substantial morphological differences. Here, we clarified the evolution of MADS-box genes across 71 extant fern species using available transcriptome, genome, and gene expression data. We obtained a total of 2,512 MADS-box sequences, ranging from 9 to 89 per species. The most recent common ancestor (MRCA) of ferns contained approximately three type I genes and at least 5-6 type II MADS-box genes. The domains, motifs, expression of type I and type II proteins, and the structure of the both type genes were conserved in ferns as to other land plants. Within type II genes, MIKC*-type proteins are involved in gametophyte development in ferns; MIKCC-type proteins have broader expression patterns in ferns than in seed plants, and these protein sequences are likely conserved in extant seed plants and ferns because of their diverse roles in diploid sporophyte development. More than 90% of MADS-box genes are type II genes, and MIKCC genes, especially CRM1 and CRM6-like genes, have undergone a large expansion in leptosporangiate ferns; the diverse expression patterns of these genes might be related to the fuctional diversification and increased complexity of the plant body plan. Tandem duplication of CRM1 and CRM6-like genes has contributed to the expansion of MIKCC genes. This study provides new insights into the diversity, evolution, and functions of MADS-box genes in extant ferns.

Diversification of Plastid Structure and Function in Land Plants.

Plastids represent a largely diverse group of organelles in plant and algal cells that have several common features but also a broad spectrum of morphological, ultrastructural, biochemical, and physiological differences. Plastids and their structural and metabolic diversity significantly contribute to the functionality and developmental flexibility of the plant body throughout its lifetime. In addition to the multiple roles of given plastid types, this diversity is accomplished in some cases by interconversions between different plastids as a consequence of developmental and environmental signals that regulate plastid differentiation and specialization. In addition to basic plastid structural features, the most important plastid types, the newly characterized peculiar plastids, and future perspectives in plastid biology are also provided in this chapter.

Survey on Tree Carbon Stock inside Mahendra Multiple Campus, Nepalgunj, Banke

Carbon stock in plant bodies is the significantly longer period reservoir for the atmospheric CO2 that causes adverse impacts on living and non-living climatic and environmental factors while increasing its proportional concentration in air. The present study aimed to estimate the carbon stock in trees of Mahendra Multiple Campus territory. The study was carried out by purposive sampling method, where altogether ten plots were laid of size 8.92m radii and measured diameter at breast height (DBH) (1.3m) and angle of inclination was taken from 5m horizontal distance from the tree pole. The calculation was made following the equation given by Chave et al., 2005 for wet forests. In total 17 species of trees were reported with the dominant species Dalbergia sissoo followed by Corymbia citriodora based on DBH and population density. The total carbon stored by trees inside the territory of MMC, Nepalgunj was 76.44 tons per hectare which is approximately 1/3rd of the world’s tropical forest average carbon stock. It implies the importance of trees outside the forest in carbon sequestration and balancing carbon emissions. Further estimation of carbon dioxide emitted from the territory, by different carbon emitters inside the area is recommended.

Water Dispersible Colloidal Metal and Metal Oxide Nanoparticles Synthesis for Agarwood Inoculation: A Review

Agarwood is one of the most expensive natural products, produced from Aquilaria Spp. These plants produce agar resin through mechanical, biological, or chemical stress. Besides these, the particles having size in the range of 1-100 nm, are known as nanoparticles, have ultra-high surface area and surface plasmon resonance, can create stress on living plants when incorporated into the plant body. Adopting this concept, we intend to produce agarwood by inoculating water-dispersible metal/metal oxide nanoparticles. Therefore, we aim to synthesize water-dispersible four noble metals (Au, Ag, Pt, Pd) and five metal oxides (Fe3O4, TiO2, SnO2, MnO2, CuO) nanoparticles in aqueous colloidal states for application in biotechnology, considering the facile synthetic routes, readily available and inexpensive precursors, and stability of the products under normal laboratory conditions for an extended period, utilizing the synthesis methods of precipitation of metal/metal oxide nanoparticles from an aqueous solution, microwave and ultrasound-assisted rapid heating methods, sol-gel methods, and surfactant-assisted microemulsion methods. We believe that by applying any of these methods, water-dispersible, long-lasting colloidal metal/metal oxide nanoparticles can be synthesized using a simple laboratory setup, without the need for sophisticated tools or instruments. IUBAT Review, 6(2): 41-76

Two-Phase Fluid Transport Phenomena in Phloem Vessels

In this study, the two-phase (particle-fluid) Newtonian fluid is studied when flowing through a sieve tube. The model of phloem is assumed with permeable walls. The flow is important for the study of the transport of food in plants. Leaves prepare food using sunlight and minerals transported from roots to leaves using xylem cells which operate predominantly on the concept of Poiseuille flow. The pressure is generated due to processes of transpiration. While prepared food is transported from leaves to stems for storage and other parts of the plant body to perform desired operations. Phloem operates with the concept of diffusion. Each phloem cell is a long tube with a permeable membrane at each end, which helps to keep the mineral fixed in food and transported to different parts of the plant. The reflection coefficient is an important parameter that helps to show the effects of the permeability of the diffusion membrane. Equations are modelled and solved using perturbation and HAM Solutions are displayed in graphical form.

STUDI ANATOMI TANAMAN KOMAK KEDIT (Phaseolus lunatus L.) LOKAL DI PULAU LOMBOK

Plant anatomy is one of the important basic data to reveal the potential of a plant. Anatomical data provide an overview of the internal structure of the plant body. This structure is influenced by the environment, the same thing is also likely to occur in Komak kedit plants which are widely planted on Lombok Island. Komak kedit (Phaseolus lunatus L.) is a species of legume (Fabaceae) originating from Central America. The purpose of this study was to analyze the differences or variations in the anatomical structure of the Komak kedit (P. lunatus) on Lombok Island. Data analysis in this research was descriptive qualitative and triangulation. The results showed that the anatomical structure of the roots, stems, leaves, flowers, fruits, and seeds of the Komak kedit plant on Lombok Island had similar structure, such as epidermis, cortex, and stele. However, in this study, there were more differences in the number of stomata on leaves in West Lombok compared to East Lombok, Central Lombok, North Lombok, and Mataram. This was caused by differences in the environment where the plants were planted, such as water content.

Integrated application of metal tolerant P. fluorescens and press mud for conferring heavy metal tolerance to aloe vera (Aloe barbadensis)

Soil pollution due to heavy metal (HM) contamination has emerged as a global issue worldwide owing to their adverse impacts on plant growth. Bioremediation approaches employing living organisms for HM alleviation have gained considerable attention among scientific community. Biological agents such as plant growth-promoting rhizobacteria (PGPR) offer a sustainable way to restore soil health, and their combination with different organic amendments such as press mud (PM) can serve as potential approach for immobilizing HMs in soil. We performed a pot experiment to evaluate the role of individual and combined application of press mud and PGPR strain ‘FQ6’ (identified as Pseudomonas fluorescens) in the phytoremediation of different HMs (Pb, Ni and Cd) and growth promotion of aloe vera. Combined application of FQ6 strain and PM yielded more significant outcomes in terms of all the growth and yield attributes such as leaf length (123 %), plant height (57 %), number of leaves (115 %), fresh and dry weights of gel (246 and 280 %), gel contents (96 %), root length (164 %), root diameter (220 %), no. of root tips (138 %) and root area (315 %), as compared to control. Combined application of FQ6 and PM also led to a significant improvement in different antioxidant activities i.e., CAT (129 %), SOD (48 %), APX (17 %) and POD (83 %) as compared to control. Contrastingly, mobility of these HMs was reduced under combined application of Pseudomonas strain ‘FQ6’ and PM, as there existed a considerable difference between HMs concentrations in soil and plant body. We concluded that joint application of HM-tolerant Pseudomonas FQ6 strain and PM could be an ideal option to alleviate the HM induced adverse impacts on aloe vera by immobilizing them in soil, and subsequently, improving plant growth.

The paschein and pathê of the Earth and Living Beings in Aristotle and Alexander of Aphrodisias (Meteorologica 1.14)

In his 2013 monograph on Structure and Method in Aristotle’s Meteorologica, Malcolm Wilson has shown both that Aristotle conceived of meteorological phenomena as analogous to the bodily processes of animals, and that for the Stagirite the sublunar world should not be seen as a single body, but rather as composed of many different individuals. However, Wilson did not articulate the relationship between these two theories—that is, he did not answer the following question: how is it possible for the Earth to behave like an animal if it is not a single body? This paper argues that the answer to this question lies in the Aristotelian statement about the different paschein of the Earth and animals. In fact, in the chapter of Meteorology dedicated to climatic changes (1.14), Aristotle, after comparing such changes to the maturing and ageing of living organisms, states that ‘only, in the case of the bodies of plants and animals being affected does not occur in each part separately, but it is necessary for the being to mature and decay all at once, whereas in the case of the Earth this occurs in each part separately, due to cooling and warming’ (351a.28-31). In his commentary, Alexander of Aphrodisias reiterates that the difference between the changes of the Earth and those of living organisms concern the way in which these different subjects undergo affections (pathê). The concept of paschein/pathos is thus fundamental to understanding how Aristotle conceives of biological analogies, which play a key role in his meteorology: as the affections of maturing and corruption show, parallels with organic processes can be found in meteorological phenomena, but always at the level of the individual parts of the Earth. Although the sublunary world can be understood in organic terms, this world is not a ‘cosmic animal’, but rather a multiplicity of ‘regional animals’. To corroborate this thesis, this paper addresses several related questions, including: the mechanics ofenvironmental changes according to Aristotle; the differences between the regions of the Earth; the lexicon used in Meteorology to refer to the transformations of the Earth; the personal notes that Alexander adds to Aristotle’s discussion. Finally, the first modern translation of the relevant section of Alexander’s commentary is also provided here.