scholarly journals Shift of seed mass and fruit type spectra along longitudinal gradient: high water availability and growth allometry

2021 ◽  
Vol 18 (2) ◽  
pp. 655-667
Author(s):  
Shunli Yu ◽  
Guoxun Wang ◽  
Ofir Katz ◽  
Danfeng Li ◽  
Qibing Wang ◽  
...  

Abstract. Propagule traits vary among biomes along geographical gradients such as longitude, but the mechanisms that underlie these variations remain unclear. This study aims to explore seed mass variation patterns of different biome types along a longitudinal gradient and their underlying variation mechanisms by involving an in-depth analysis on the variation of seed mass, fruit type spectra, growth forms and dispersal mode spectra in Inner Mongolia and northeastern China. Plant community characterization and seed collection were conducted in 26 sites spreading over five vegetation types and covering 622 species belonging to 66 families and 298 genera. We found there are significantly declining trends for mean seed mass, vertebrate-dispersed species richness and fleshy-fruited species richness along a longitudinal gradient from forests to desert grasslands. However, we also found the lowest average seed mass and the smallest proportion of species dispersed by vertebrates occurring at typical grasslands in the five biomes. The variations of average seed mass display high congruence with transition of growth form spectra. The selection for these propagule attributes is driven mainly by climatic factors such as precipitation, temperature, soil moisture and evaporation, as well as by internal biotic factors such as growth forms, canopy coverage and leaf area (Ackerly and Donoghue, 1998). A hypothesis was provided that environmental factors and botanical traits that favor greater water availability lead to emergence (or speciation) of species with large seeds or fleshy fruits with high water content. Due to greater water availability and increasing leaf area, much more photosynthate (photosynthesis production) and allometric growth then ultimately increase the biome average seed mass from west to east. Phylogenetic signal or diversity are not found to be significantly involved in the effect on the patterns. A novel mechanistic framework and mathematical model are provided to expound seed variation among species or biomes.

2020 ◽  
Author(s):  
Shunli Yu ◽  
Guoxun Wang ◽  
Ofir Katz ◽  
Danfeng Li ◽  
Qibing Wang ◽  
...  

Abstract. Propagule traits vary among communities along geographical gradients such as longitude, but the mechanisms that underlie these variations remain unclear. This study aims to explore seed mass variation patterns of different community types along a longitudinal gradient and their underlying variation mechanisms by involving an in-depth analysis on the variation of seed mass, fruit type spectra, growth forms and dispersal mode spectra in Inner Mongolia and northeastern China. Plant community characterization and seed collection were conducted in 26 sites spreading over five vegetation types and covering 622 species belonging to 66 families and 298 genera. We found there are significantly declining trend for mean seed mass, vertebrate-dispersed species richness and fleshy-fruited species richness along a longitudinal gradient from forests to desert grasslands. However, we also found the lowest average seed mass and the smallest proportion of species dispersed by vertebrates occurring at typical grasslands in the five communities. The variations of average seed mass display high congruent with transition of growth forms. The selection for these propagule attributes is driven mainly by climatic factors such as precipitation, temperature, soil moisture and evaporation, as well as by internal biotic factors such as growth forms, canopy coverage and leaf area. A hypothesis was provided that environmental factors and botanical traits that favor greater water availability lead to emergence (or speciation) of species with large seeds or fleshy fruits with high water content. Due to greater water availability and increasing leaf area, much more photosynthate and allometric growth then ultimately increase the community average seed mass along rising longitude (or declining latitude or elevation). Phylogenetic signal or diversity are not found to be involved into the effect on the patterns. A novel mechanistic framework and model are provided to expound seed variation among species or communities.


2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Conrad Zeidler ◽  
Vincent Vrakking ◽  
Matthew Bamsey ◽  
Lucie Poulet ◽  
Paul Zabel ◽  
...  

AbstractIn the next 10 to 20 years humankind will return to the Moon and/or travel to Mars. It is likely that astronauts will eventually build permanent settlements there, as a base for long-term crew tended research tasks. It is obvious that the crew of such settlements will need food to survive. With current mission architectures the provision of food for longduration missions away from Earth requires a significant number of resupply flights. Furthermore, it would be infeasible to provide the crew with continuous access to fresh produce, specifically crops with high water content such as tomatoes and peppers, on account of their limited shelf life. A greenhouse as an integrated part of a planetary surface base would be one solution to solve this challenge for long-duration missions. Astronauts could grow their own fresh fruit and vegetables in-situ to be more independent from supply from Earth. This paper presents the results of the design project for such a greenhouse, which was carried out by DLR and its partners within the framework of the Micro-Ecological Life Support System Alternative (MELiSSA) program. The consortium performed an extensive system analysis followed by a definition of system and subsystem requirements for greenhouse modules. Over 270 requirements were defined in this process. Afterwards the consortium performed an in-depth analysis of illumination strategies, potential growth accommodations and shapes for the external structure. Five different options for the outer shape were investigated, each of them with a set of possible internal configurations. Using the Analytical Hierarchy Process, the different concept options were evaluated and ranked against each other. The design option with the highest ranking was an inflatable outer structure with a rigid inner core, in which the subsystems are mounted. The inflatable shell is wrapped around the core during launch and transit to the lunar surface. The paper provides an overview of the final design, which was further detailed in a concurrent engineering design study. During the study, the subsystem parameters (e.g. mass, power, performance) were calculated and evaluated. The results of the study were further elaborated, leading to a lunar greenhouse concept that fulfils all initial requirements. The greenhouse module has a total cultivation area of more than 650 m² and provides more than 4100 kg of edible dry mass over the duration of the mission. Based on the study, the consortium also identified technology and knowledge gaps (not part of this paper), which have to be addressed in future projects to make the actual development of such a lunar greenhouse, and permanent settlements for long-term human-tended research tasks on other terrestrial bodies, feasible in the first place.


2020 ◽  
pp. 1826-1833
Author(s):  
Thâmara M. Lima ◽  
Elizabeth S. Amaral ◽  
Fernanda A. Gaiotto ◽  
Letícia dos Anjos ◽  
Ândrea Carla Dalmolin ◽  
...  

Carpotroche brasiliensis (RB) A. Gray (Achariaceae) is a native tree species of the Brazilian Atlantic Forest with great potential provide natural forest products in agroforestry systems. The oil of its seeds contains medicinal and cosmetic properties, and the fruits are appreciated by wild animals. In this study, we analyzed the biometry of fruits and seeds collected from naturally-grown trees in agroforestry systems on small farms in southern Bahia, Brazil. Fresh fruit mass (FFM), fruit length (FL), fruit diameter (FD), number of seeds per fruit (NSF), total fresh seed mass per fruit (FSMF), total dry mass of seeds per fruit (DMSF), and mass of 1,000 seeds (MTS) were collected from 66 fruits of 18 trees on six rural properties. Seed length (SL) and seed diameter (SD) were also evaluated for 5335 seeds. From this sample universe, 697 seeds represented an adequate sample size to measure these dimensions with statistical precision. The fruits analyzed in this study had uniform values for most of the biometric variables among the sites. The average values of NSF, FFM, and MTS were approximately 88 seeds, 0.5 kg, and 1.3 kg, respectively. Seeds of C. brasiliensis obtained from freshly-harvested fruits had high water content, with an average of more than 45%. Strongly significant correlations between FFM and FD and between FMSF and DMSF indicate the possibility of developing simple procedures to estimate seed pro-duction for commercial purposes from field evaluations


Author(s):  
A. Bykov ◽  
D. Palatov ◽  
I. Studenov ◽  
D. Chupov

The article provides information about the features of spring feeding of sterlet in the spawning grounds of the middle course of the Northern Dvina river in may 2019. The main and secondary groups of forage objects in the diet of this species of sturgeon are characterized. The article considers the variability of the sterlet food composition with an increase in the size of fish from 30 to 60 cm. In the process of fish growth in the diet of the Severodvinsk sterlet, the main components in terms of occurrence and mass in all size groups are the larvae of Brooks and chironomids. A minor occurrence was the larvae of midges, biting midges, stoneflies, mayflies and small clams. To random and seasonal food are the larvae of water bugs, butterflies, flies, beetles and eggs of other fish. The feeding intensity of the smaller sterlet (30–40 cm) was significantly higher than that of the fish in the size groups 40–50 and 50–60 cm. Fundamental changes in the diet of the Severodvinsk sterlet for the main food objects for more than sixty years of observations have not been established. During periods of high water content of the Northern Dvina due to seasonal changes in the structure of benthic communities, the value of Brooks in the diet of sterlet increases and the proportion of chironomids decreases.


2018 ◽  
Vol 24 (8) ◽  
pp. 843-854 ◽  
Author(s):  
Weiguo Xu ◽  
Shujun Dong ◽  
Yuping Han ◽  
Shuqiang Li ◽  
Yang Liu

Hydrogels, as a class of materials for tissue engineering and drug delivery, have high water content and solid-like mechanical properties. Currently, hydrogels with an antibacterial function are a research hotspot in biomedical field. Many advanced antibacterial hydrogels have been developed, each possessing unique qualities, namely high water swellability, high oxygen permeability, improved biocompatibility, ease of loading and releasing drugs and structural diversity. In this article, an overview is provided on the preparation and applications of various antibacterial hydrogels. Furthermore, the prospects in biomedical researches and clinical applications are predicted.


2019 ◽  
Vol 67 (7) ◽  
pp. 4803-4810 ◽  
Author(s):  
Xiong Wang ◽  
Tao Qin ◽  
Yexian Qin ◽  
Ahmed H. Abdelrahman ◽  
Russell S. Witte ◽  
...  

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Shun-ichiro Karato ◽  
Bijaya Karki ◽  
Jeffrey Park

AbstractOceans on Earth are present as a result of dynamic equilibrium between degassing and regassing through the interaction with Earth’s interior. We review mineral physics, geophysical, and geochemical studies related to the global water circulation and conclude that the water content has a peak in the mantle transition zone (MTZ) with a value of 0.1–1 wt% (with large regional variations). When water-rich MTZ materials are transported out of the MTZ, partial melting occurs. Vertical direction of melt migration is determined by the density contrast between the melts and coexisting minerals. Because a density change associated with a phase transformation occurs sharply for a solid but more gradually for a melt, melts formed above the phase transformation depth are generally heavier than solids, whereas melts formed below the transformation depth are lighter than solids. Consequently, hydrous melts formed either above or below the MTZ return to the MTZ, maintaining its high water content. However, the MTZ water content cannot increase without limit. The melt-solid density contrast above the 410 km depends on the temperature. In cooler regions, melting will occur only in the presence of very water-rich materials. Melts produced in these regions have high water content and hence can be buoyant above the 410 km, removing water from the MTZ. Consequently, cooler regions of melting act as a water valve to maintain the water content of the MTZ near its threshold level (~ 0.1–1.0 wt%). Mass-balance considerations explain the observed near-constant sea-level despite large fluctuations over Earth history. Observations suggesting deep-mantle melting are reviewed including the presence of low-velocity anomalies just above and below the MTZ and geochemical evidence for hydrous melts formed in the MTZ. However, the interpretation of long-term sea-level change and the role of deep mantle melting in the global water circulation are non-unique and alternative models are reviewed. Possible future directions of studies on the global water circulation are proposed including geodynamic modeling, mineral physics and observational studies, and studies integrating results from different disciplines.


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