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1. Many ecological models of plant growth assume balanced growth: that biomass is allocated preferentially to leaves or roots to increase capture of the limiting external resource. An alternative explanation is based on nonlinear (allometric) allocation as a function of plant size. The objective of this study was to test between these two alternative explanations. 2. A total of 1150 plants from 22 different herbaceous species were grown in hydroponic sand culture in factorial combinations of high (1100 μmol m-2s-1) and low (200 μmol m-2s-1PAR) irradiance crossed with a full-strength and a 1/6 dilution of Hoagland's hydroponic solution. Plants were harvested at 15, 20, 25, 30 and 35 days postgermination, and dry mass was determined for leaf and root components. These data were used to test the hypotheses of balanced growth and of allometric allocation. 3. Both irradiance and nutrient supply affected the slope and intercept of the root: shoot allometry, contrary to the allometric hypothesis but in agreement with the hypothesis of balanced growth; decreased nutrient supply increased allocation to roots; and decreased irradiance increased allocation to leaves. 4. Plants allocated relatively more biomass to roots than to leaves as plants grew larger. In order for the balanced-growth hypothesis to be correct, the net rate of nutrient uptake per unit root mass must have been decreasing relative to the net rate of carbon gain per unit leaf mass. 5. We suggest two reasons why this might be the case: (i) older roots decreased their efficiency of nutrient uptake; and (ii) larger root systems more rapidly decreased the available nutrients between flushes of hydroponic solution. 6. These results support the notion of balanced growth that is found in many ecological models of plant growth.

Background and aims Hostile soil conditions have a global impact on crop production. While root traits of individual plant species adapted to specific hostile soils are well studied, a comprehensive synthesis of how to use diversified cropping systems with complementary root growth strategies to adapt to and remediate hostile soils is lacking. Scope We begin by providing definitions, categorizations, and global distribution of hostile soils, followed by a synthesis of recent advances in below-ground niche complementarity or facilitative root interactions among crop species in diverse cropping systems across various hostile soils. Lastly, we highlight the significance of cultivating a robust understanding of root adaptations for crop diversification in hostile soils for future research. Conclusion Diversified cropping systems that incorporate complementary root growth strategies can efficiently utilize nutrients and mitigate abiotic stress in hostile soils, such as nutrient deficiency, aridity, and waterlogging conditions. Furthermore, intercropping hyperaccumulator plants or halophytes with crops is effective in reducing metal or salt accumulation in target crops grown in contaminated or saline-alkali soils, respectively. Cover crops could create biopores for succeeding crop roots in compacted soils, while diversified cropping systems aid in preventing additional soil erosion in eroded areas. Leveraging diverse root traits can also contribute to the suppression of soil‑borne diseases and pests within intercropping setups. Enhancing diversified cropping systems necessitates the application of novel methods and technologies for root studies. This multifaceted approach is crucial for sustaining yield under the challenges posed by multiple hostile soil conditions, especially within the context of climate change.

1. A plant's growth rate is seen as a central element of its ecological strategy, and as determined by its traits. Yet the literature is inconsistent about the empirical correlation between functional traits and growth, casting doubt on the capacity of some prominent traits to influence growth rate. 2. We propose that traits should influence growth in a way that depends on the size of individual plants. We outline mechanisms and hypotheses based on new theoretical work and test these predictions in tree species using a meta-analysis of 103 studies (> 500 correlations) for five traits (specific leaf area, wood density, maximum height, seed mass and maximum assimilation rate). We also recorded data for 14 other traits commonly used in the trait literature. To capture the effects of plant size, we tested for a shift in the direction of correlation between growth rates and each trait across three ontogenetic stages: seedling, sapling and adult. 3. Results were consistent with predictions, although there were some limitations arising from unequal numbers of observation across ontogenetic stages. Specific leaf area was correlated with relative growth rate in seedlings but not in adult plants. Correlations of growth with wood density were not affected by ontogenetic stage. Seed mass, assimilation rate and maximum height were correlated with relative growth rate only in one ontogenetic stage category: seedlings, seedlings and adults, respectively. 4. Although we were able to confirm several of our theoretical predictions, major knowledge gaps still exist in the trait literature. For example, for one-third of the traits considered, the majority (> 75%) of reported correlations with growth came from the same ontogenetic stage. 5. Synthesis. We show for some traits, how trait–growth correlations change in a predictable way with plant size. Our understanding of plant strategies should shift away from describing species as having a fixed growth strategy throughout their life (on a continuous axis from slow to fast growth), in favour of a size-dependent growth trajectories.

Despite the prominent role played by B2B electronic platforms (E-platforms) in assisting exporters, extant research pays scant attention to how, and under what conditions, exporters can deploy B2B E-platforms to enhance their sales performance. Drawing on signaling theory, we examine how the deployment of E-platforms affects export sales performance via foreign buyer contact. We also explore the moderating roles of institutional environment and export growth strategy. We test our model with a dataset composed of a survey and archival data on Chinese exporters that subscribe to Alibaba. com. The findings indicate that E-platform use positively affects foreign buyer contact and, in turn, export sales performance. This positive effect is even more substantial when exporters originate from regions with less-developed market intermediaries or when the institutional distance between the home and host countries is greater. In contrast, this effect becomes weaker when the level of export market diversification or product diversification is higher.

This paper examines the impact of improvements in marketing skills relative to finance skills among small-scale entrepreneurs. It addresses three important questions: (1) What is the impact of marketing or finance skills on business profits? (2) How do improvements in marketing and finance skills respectively affect different business outcomes? (3) When are increases in marketing relative to finance skills more beneficial? Through a randomized control study of 852 firms in South Africa, the analysis finds significant improvements in profitability from both types of business skills training. However, the pathways to achieve these gains differ substantially between the two groups. The marketing group achieves greater profits by adopting a growth focus on higher sales, greater investments in stock and materials, and hiring more employees. The finance group achieves similar profit gains but through an efficiency focus on lower costs. Both groups show significantly higher adoption of business practices related to their respective training program. Consistent with a growth focus, marketing/sales skills are significantly more beneficial to businesses run by entrepreneurs with ex ante less exposure to different market contexts. In contrast and in line with an efficiency focus, it is the more established businesses that benefit significantly more from finance/accounting skills. This paper was accepted by Eric Anderson, marketing. Data and the online appendix are available at https://doi.org/10.1287/mnsc.2017.2920 .

Firms that have failed to meet the performance expectations of investors must seek new ways of creating value or face the loss of financial support. Using resource-based arguments, we find that valuable and difficult-to-imitate strategies that recombine the firm's existing stock of resources to create new products, processes, or technologies have a positive effect on organizational recovery as measured by investors' expectations. Similarly, acquiring new resources through mergers or acquisitions also has positive effects on investors' expectations. In contrast, valuable and difficult-to-imitate strategies that provide the firm with access to new resources through alliances or joint ventures do not affect investors' expectations of performance. We also find that taking actions that are not valuable and difficult-to-imitate either have no effect on performance or may lead to further performance declines. Lastly, our results show that valuable and difficult-to-imitate strategic actions that use existing resources in new ways contribute the most to organizational recovery.

The diversity of forest tree life strategies is fundamental to species coexistence in mixed stands. Growth rate is one of the most important elements of a species’ life strategy. This aspect has been relatively well recognised in even-aged stands. However, the situation is different in uneven-aged stands, particularly in multi-species stands comprising species with different light demands. In this study, we aimed to compare stem basal area increment (BAI) in regard to five species forming multi-species, uneven-aged deciduous forests in Central Europe as an important element of their growth strategy. Particular attention was paid to the relationship between this feature and tree height and competitive status. These relationships were analysed using a linear mixed model. The BAI was positively correlated with tree height, while a negative correlation was observed between BAI and increasing competitive level. However, the observed variations in the trends of these relationships were not associated with the light demands of the compared species. In general, the majority of the studied species demonstrated similar growth dynamics. This may suggest that the role of this trait in shaping species coexistence is modulated by other life-history strategy components and by specific growth conditions. An exception to this is the most light-demanding species, black alder (Alnus glutinosa (L.) Gaertner), which, contrary to expectations, exhibits a lower basal area increment under uneven-aged conditions.

Aims Tropical perennial grasses that can rapidly establish deep roots have a greater potential to survive soil surface drying sooner after establishment. This research aimed to identify species that establish deep roots quickly and to investigate the mechanisms that drove rapid vertical root development. Methods Perennial grass species Brachiaria brizantha , Brachiaria decumbens , Brachiaria humidicola , Brachiaria hybrid Mulato II, Brachiaria mosambicensis , Panicum maximum , Setaria sphacelata and Cynodon dactylon were grown in rhizotrons that facilitated measurement of the rate of root depth development, the rate of root length development, photosynthesis and morphological traits. Principal component analysis was employed to separate grass species according to functional traits of vertical root development and their growth strategies. Results P. maximum established roots more rapidly to 50 cm depth than the other species examined and accumulated biomass and leaf area faster. It was differentiated from other species by a greater percentage of fine root length (< 0.2 mm diameter), a higher photosynthetic rate and ratio of root length to leaf area according to the principal component analysis. The growing degree days required for root establishment to 50 cm depth was negatively correlated with the percentage of fine root length, and positively correlated with root angle. The exponential rate of root depth development per growing degree day increased with average root diameter in B. humidicola and B. hybrid Mulato II, indicating a conservative growth strategy. Conclusion Rapid vertical root development with a narrow root angle, higher photosynthetic rate, higher ratio of root length to leaf area and higher percentage of fine roots were apparent mechanisms that enabled P. maximum to establish deep roots faster than other species. P. maximum appears to be better able to avoid water stress during surface drying by accessing profile moisture. Greater average root diameter and percentage of root length with higher diameters was related to increased exponential rate of root depth development and wide root angle.

Soil microbes respond to environmental change by altering how they allocate carbon to growth versus respiration—or carbon use efficiency (CUE). Ecosystem and Earth System models, used to project how global soil C stocks will continue to respond to the climate crisis, often assume that microbes respond homogeneously to changes in the environment. In this study, we quantified how CUE varies with changes in temperature and substrate quality in soil bacteria and evaluated why CUE characteristics may differ between bacterial isolates and in response to altered growth conditions. We found that bacterial taxa capable of rapid growth were more efficient than those limited to slow growth and that taxa with high CUE were more likely to become less efficient at higher temperatures than those that were less efficient to begin with. Together, our results support the idea that the CUE temperature response is constrained by both growth rate and CUE and that this partly explains how bacteria acclimate to a warming world. The strategy that microbial decomposers take with respect to using substrate for growth versus maintenance is one essential biological determinant of the propensity of carbon to remain in soil. To quantify the environmental sensitivity of this key physiological trade-off, we characterized the carbon use efficiency (CUE) of 23 soil bacterial isolates across seven phyla at three temperatures and with up to four substrates. Temperature altered CUE in both an isolate-specific manner and a substrate-specific manner. We searched for genes correlated with the temperature sensitivity of CUE on glucose and deemed those functional genes which were similarly correlated with CUE on other substrates to be validated as markers of CUE. Ultimately, we did not identify any such robust functional gene markers of CUE or its temperature sensitivity. However, we found a positive correlation between rRNA operon copy number and CUE, opposite what was expected. We also found that inefficient taxa increased their CUE with temperature, while those with high CUE showed a decrease in CUE with temperature. Together, our results indicate that CUE is a flexible parameter within bacterial taxa and that the temperature sensitivity of CUE is better explained by observed physiology than by genomic composition across diverse taxa. We conclude that the bacterial CUE response to temperature and substrate is more variable than previously thought. IMPORTANCE Soil microbes respond to environmental change by altering how they allocate carbon to growth versus respiration—or carbon use efficiency (CUE). Ecosystem and Earth System models, used to project how global soil C stocks will continue to respond to the climate crisis, often assume that microbes respond homogeneously to changes in the environment. In this study, we quantified how CUE varies with changes in temperature and substrate quality in soil bacteria and evaluated why CUE characteristics may differ between bacterial isolates and in response to altered growth conditions. We found that bacterial taxa capable of rapid growth were more efficient than those limited to slow growth and that taxa with high CUE were more likely to become less efficient at higher temperatures than those that were less efficient to begin with. Together, our results support the idea that the CUE temperature response is constrained by both growth rate and CUE and that this partly explains how bacteria acclimate to a warming world.

PurposeThe aim of this paper is to investigate the role of boundary management when firms should implement open innovation.Design/methodology/approachThe relevant literature on strategic management, firm boundaries and open innovation fields is revised and critically assessed. An interpretive-qualitative methodology is applied to analyse empirical data obtained from a questionnaire and subsequent interviews of a sample of Italian listed firms. By critically integrating literature review and empirical analysis, a framework is provided with the objective of supporting open innovation implementation.FindingsThe study shows that on the one hand, open innovation and many modern paths of growth are connected to a firm's boundaries and that on the other hand, boundary management plays a key role in the implementation of open innovation.Practical implicationsThe paper has implications for practitioners by driving them to shift the focus of open innovation implementation towards the management of boundaries, in which boundary capabilities and activities play a key role.Originality/valueThis paper sheds light on the advantages and risks that can jeopardize a successful opening up innovation processes without the effective management of boundary studies. Thus, the authors identify and propose causes for reflection and tools maximizing potentiality and reducing risks in the implementation of such processes.