Browsing by Author "López IF"
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- Item18O isotopic labelling and soil water content fluctuations validate the hydraulic lift phenomena for C3 grass species in drought conditions(Elsevier B.V., 2024-02-29) Oliveira BA; López IF; Cranston LM; Kemp PD; Donaghy DJ; Dörner J; López-Villalobos N; García-Favre J; Ordóñez IP; Van Hale RHydraulic lift is a functional characteristic observed in some plant species, often associated with their ability to withstand drought conditions. It involves capturing water from deep soil layers and redistributing it to shallower soil layers through the plant's roots. Bromus valdivianus Phil., Dactylis glomerata L., and Lolium perenne L. may perform hydraulic lift at varying rates. Using both direct (isotopic labelling - δ18O) and indirect (soil water content sensors) techniques, the study assessed and validated the hydraulic lift under extreme drought conditions on the soil top layer (below permanent wilting point), maintaining the bottom layer at high (20–25% filed capacity [FC]) and low (80–85% FC) levels of soil water restriction. Above- and below-ground biomass growth and morpho-physiological responses were evaluated. All species displayed some degree of hydraulic lift, with significant differences observed in the isotopic analysis and soil water content (p > 0.05). This illustrates that water was redistributed from the deep to shallower soil layer and validates that the hydraulic lift phenomenon is occurring in these C3 grasses. Bromus valdivianus presented the highest δ18O values (25.05‰) and highest increases in soil water content (µ=0.00626 m3 m−3; five events). Bromus valdivianus had a dry matter ratio of approximately 4:1 (0–20cm:20–40 cm). In contrast, L. perenne and D. glomerata had approximately 6:1 and 5:1, respectively. This difference in root morphology may explain the higher rate of hydraulic lift observed in B. valdivianus relative to L. perenne and D. glomerata. This paper validates the occurrence and provides initial insights into the hydraulic lift process occurrence of temperature grass species.
- ItemAboveground Structural Attributes and Morpho-Anatomical Response Strategies of Bromus valdivianus Phil. and Lolium perenne L. to Severe Soil Water Restriction(MDPI (Basel, Switzerland), 2023-12-01) Zhang Y; García-Favre J; Hu H; López IF; Ordóñez IP; Cartmill AD; Kemp PD; Głab TGrass species have a range of strategies to tolerate soil water restriction, which are linked to the environmental conditions at their site of origin. Climate change enhances the relevance of the functional role of anatomical attributes and their contribution as water stress tolerance factors. Morpho-anatomical traits and adjustments that contribute to drought resistance in Lolium perenne L. (Lp) and Bromus valdivianus Phil. (Bv), a temperate humid grass species, were analysed. The structure of the leaves and pseudostems (stems only in Lp) grown at 20–25% field capacity (FC) (water restriction) and 80–85% FC (control) were evaluated by making paraffin sections. In both species, water restriction reduced the thickness of the leaves and pseudostems, along with the size of the vasculature. Bv had long and dense leaf hairs, small and numerous stomata, and other significant adaptive traits under water stress, including thicker pseudostems (p ≤ 0.001), a greatly thickened bundle sheath wall (p ≤ 0.001) in the pseudostem to ensure water flow, and a thickened cuticle covering on leaf surfaces (p ≤ 0.01) to avoid water loss. Lp vascular bundles developed throughout the stem, and under water restriction the xylem vessel walls were strengthened and lignified. Lp leaves had individual traits of a ribbed/corrugated-shaped upper surface, and the stomata were positioned to maintain relative humidity outside the leaf surface. Water restriction significantly changed the bulliform cell depth in Lp (p ≤ 0.05) that contributed to water loss reduction via the curling leaf blade. This study demonstrated that the two grass species, through different morphological traits, were able to adjust their individual tissues and cells in aboveground parts to reach similar physiological functions to reduce water loss with increased water restriction. These attributes explain how both species enhance persistence and resilience under soil water restriction.
- ItemCorrection to: A Framework for Reviewing Silvopastoralism: A New Zealand Hill Country Case Study (Land, (2021), 10, 12, (1386)(MDPI (Basel, Switzerland), 2023-03-22) Mackay-Smith TH; Burkitt L; Reid J; López IF; Phillips CThe authors would like to make the following correction to the published article [1]. There was a miscommunication with the journal editors regarding the formatting of the table. Individual points within table boxes were removed for the final manuscript so there were duplicate references in each table box. The following changes were made to the references in Table 2: “McIvor et al. [42]” was removed from Page 8; “Charlton et al. [25]” was removed from Page 10; “Marden and Phillips [49]”, “Charlton et al. [25]” and “Boffa Miskell Limited [50]” × 2 were removed from Page 11 and from Page 10. Additionally, colons were added between references where necessary. Other changes include the following: “survivial” was changed to “survival” on Page 11; “Quantatiative” was changed to “quantitative” on Page 11; to was removed on Page 11; “precence” was changed to “presence” on Page 13; “11.5 year old” was changed to “11.5-year-old” on Page 8; “16 year-old” was changed to “16-year-old” on Page 8; “32.0-year-old” was changed to “32-year-old” on Page 8; and “5.0, 7.0 and 9.5 year old” changed to “5, 7, and 9.5 years old”. Finally, “≥25 m” was changed to “>30 m” and “10–20 m” was changed to 8–20 m” on Page 7 due to ongoing research refining the sizes of the tree. The corrected Table 2 appears below. Tree attributes for poplar (Populus spp.) and kānuka (Kunzea spp.) in a New Zealand hill country silvopastoral system. Tree attributes have been adapted from Wood [15]. The photographs were taken by the lead author. The following changes were made to the references in Table 3: “Guevara-Escobar et al. [26]” and “Wall [27]” were removed from Page 14, and “Guevara-Escobar et al. [26]” was removed from Page 16. Additionally, the Table 3 header was moved to the left and the font size of Table 3 was adjusted to size 8. The corrected Table 3 appears below. Silvopastoral outcomes for poplar (Populus spp.) and kānuka (Kunzea spp.) in a New Zealand hill country silvopastoral system. Tree outcomes have been adapted from Wood [15]. There was an error in the original publication. “Forst.” should be “(G. Forst.) Oerst.” A correction has been made to Section 1. Introduction, paragraph 1: Page 1. There was an error in the original publication. “>15” has been changed to “> 15”. A correction has been made to Section 1. Introduction, paragraph 3: Page 1. There was an error in the original publication. “(Populus spp.)” and “(Salix spp.)” have been removed. A correction has been made to Section 3.1. Poplar and Willow, paragraph 1: Page 5. There was an error in the original publication. “40 year” has been changed to “40-year”. A correction has been made to Section 3.1. Poplar and Willow, paragraph 2: Page 5. There was an error in the original publication. “serotine” should be “serotina”. A correction has been made to Section 3.2. Kānuka, paragraph 1: Page 6. There was an error in the original publication. “(Leptospermum scoparium)” has been removed. A correction has been made to Section 3.2. Kānuka, paragraph 2: Page 6. There was an error in the original publication. The reference “[23,24,25]” should be “[25]”. A correction has been made to Section 4.1. The interaction of Poplar and Kānuka with the Pasture and Soil, paragraph 5: Page 21. There was an error in the original publication. “400-years-old” should be “400 years old”. A correction has been made to Section 4.2. Longevity, paragraph 1: Page 21. There was an error in the original publication. Reference [80] should be removed after kiwi-fruit orchards. A correction has been made to Section 4.6. Bird biodiversity, paragraph 2: Page 22. There was an error in the original publication. “2 year” should be “2-year”. A correction has been made to Section 4.6. Bird biodiversity, paragraph 2: Page 22. There was an error in the original publication. “(Leptospermum scoparium)” has been removed. A correction has been made to Section 4.7. Additional Income, paragraph 1: Page 23. There was an error in the original publication. “7-years-old” should be “7 years old”. A correction has been made to Section 4.7. Additional Income, paragraph 3: Page 23. There was an error in the original publication. Reference [46] has been changed to [52]. A correction has been made to Section 4.7. Additional Income, paragraph 4: Page 23. There was an error in the original publication. reference [52] should be “Ministry for Primary Industries. Forest land in the ETS. Available online: https://www.mpi.govt.nz/forestry/forestry-in-the-emissions-trading-scheme/forest-land-in-the-ets/ (accessed on 8 May 2020)”. A correction has been made to References section: Page 27. The authors apologize for any inconvenience caused and state that the scientific conclusions are unaffected. The original publication has also been updated.
- ItemEffects of combined nitrogen and phosphorus application on soil phosphorus fractions in alfalfa (Medicago sativa L.) production in China.(Frontiers Media S.A., 2024-05-28) Yang K; Li S; Sun Y; Cartmill AD; López IF; Ma C; Zhang Q; Nazir RNitrogen (N) and phosphorus (P) fertilizers change the morphological structure and effectiveness of P in the soil, which in turn affects crop growth, yield, and quality. However, the effects and mechanism of combined N and P application on the content of P fractions and the transformation of effective forms in alfalfa (Medicago sativa L.) production is unclear. This experiment was conducted with four levels of N: 0 (N0), 60 (N1), 120 (N2) and 180 kg·ha-1 (N3); and two levels of P (P2O5): 0 (P0) and 100 kg·ha-1 (P1). The results indicated that, under the same N level, P application significantly increased soil total N, and total P, available P, and content of various forms of inorganic P when compared to no P application, while decreasing the content of various forms of organic P and pH value. In general, under P0 conditions, soil total N content tended to increase with increasing N application, while total P, available P content, pH, inorganic P content in all forms, and organic P content in all forms showed a decreasing trend. When compared to no N application, insoluble P (Fe-P, O-P, Ca10-P) of the N application treatments was reduced 2.80 - 22.72, 2.96 - 20.42, and 5.54 - 20.11%, respectively. Under P1 conditions, soil total N and O-P tended to increase with increasing N application, while, pH, Ca2-P, Al-P, Fe-P, Ca10-P, and organic P content of each form tended to decrease. Total P, available P, and labile organic P (LOP) of N application reduced 0.34 - 8.58, 4.76 - 19.38, and 6.27 - 14.93%, respectively, when compared to no application. Nitrogen fertilization reduced the soil Ca2-P ratio, while P fertilization reduced soil Fe-P, moderately resistant organic P (MROP), and highly resistant P (HROP) ratios, and combined N and P elevated the Ca8-P to LOP ratio. The results of redundancy analysis showed that soil total N content, available P content, and pH were the key factors affecting the conversion of P fractions in the soil. Nitrogen and P reduced the proportion of soil insoluble P, promoted the activation of soil organic P, resulting in accumulation of slow-acting P in the soil, thereby improving the efficiency of soil P in alfalfa production.
- ItemHill country pastures in the southern North Island of New Zealand: an overview(New Zealand Grassland Association, 2016-04-26) López IF; Kemp PDThe 4 million ha of hill country pastures in New Zealand grow mostly on steep slopes and soils of naturally low soil fertility. Pastures are based on approximately 25 exotic species introduced within the last 130 years after the forest was cleared and burnt. Despite the environmental constraints and naturalised species, hill country is a major contributor to agricultural exports. The landscape and the pastures are spatially diverse, with slope and aspect strongly influencing the abundance and production of pasture species. The number of pasture species present is relatively stable, but the relative abundance of high fertility grass species (e.g. perennial ryegrass, Lolium perenne), low fertility grass species (e.g. browntop, Agrostis capillaris) and legumes (e.g. white clover, Trifolium repens) can be shifted towards high fertility grass species and legumes through the interaction of phosphate fertiliser application and grazing decisions (that is, sheep versus cattle, stocking rate, grazing management). Increased proportions of desirable species and improved soil fertility and structure can support sustainable farming systems. There are challenges such as soil erosion and nutrient loss into waterways, but these are more readily managed when the pastoral system is productive and profitable
- ItemPhysico-Chemical Characteristics and In Vitro Gastro-Small Intestinal Digestion of New Zealand Ryegrass Proteins(MDPI (Basel, Switzerland), 2021-02-04) Kaur L; Lamsar H; López IF; Filippi M; Ong Shu Min D; Ah-Sing K; Singh J; Moreno FJBeing widely abundant, grass proteins could be a novel source of plant proteins for human foods. In this study, ryegrass proteins extracted using two different approaches-chemical and enzymatic extraction, were characterised for their physico-chemical and in vitro digestion properties. A New Zealand perennial ryegrass cultivar Trojan was chosen based on its higher protein and lower dry matter contents. Grass protein concentrate (GPC) with protein contents of approximately 55 and 44% were prepared using the chemical and enzymatic approach, respectively. The thermal denaturation temperature of the GPC extracted via acid precipitation and enzymatic treatment was found to be 68.0 ± 0.05 °C and 66.15 ± 0.03 °C, respectively, showing significant differences in protein's thermal profile according to the method of extraction. The solubility of the GPC was highly variable, depending on the temperature, pH and salt concentration of the dispersion. The solubility of the GPC extracted via enzymatic extraction was significantly lower than the proteins extracted via the chemical method. Digestion of raw GPC was also studied via a gastro-small intestinal in vitro digestion model and was found to be significantly lower, in terms of free amino N release, for the GPC prepared through acid precipitation. These results suggest that the physico-chemical and digestion characteristics of grass proteins are affected by the extraction method employed to extract the proteins. This implies that selection of an appropriate extraction method is of utmost importance for achieving optimum protein functionality during its use for food applications.