Growth and Chemical Composition of Pistachio Cultivars as Influenced by Irrigation Regimes and Salinity Levels of Irrigation Water. 1. Growth

Saline irrigation water is becoming an important water source as fresh water is fast becoming a scarce resource in many areas of the world, including Eswatini, especially in arid and semi-arid regions. A study to test the response of two varieties of spinach (fordhook giant and mustard) to salinity was conducted in a field pot experiment at the Faculty of Agriculture at the Luyengo Campus of the University of Eswatini. The treatments were laid in a randomized block design (RCBD). The experiment consisted of four treatments, each replicated twelve times. Treatments were salinity levels of 0.0 dS/m, 1.5 dS/m, 2.0 dS/m and 3.5 dS/m. All the treatments were subjected to similar agronomic practices. Spinach was grown and observed for a period of five weeks. Plant height was measured and the number of leaves counted weekly throughout the experiment. Significant differences (P < 0.05) between salinity treatments were obtained for plant height beginning in week 2 but were more pronounced in week 3, 4 and week 5. No significant differences were obtained for the number of leaves. There were however, clear significant differences between spinach irrigated with none saline irrigation water compared to saline irrigation water. It was concluded that irrigating spinach with saline water of more than 2.0 dS/m drastically reduce plant growth but not the number of leaves under the conditions of the experiment.

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Latitudinal, seasonal and depth-dependent variation in growth, chemical composition and biofouling of cultivated Saccharina latissima (Phaeophyceae) along the Norwegian coast

Journal of Applied Phycology ◽

10.1007/s10811-020-02038-y ◽

2020 ◽

Vol 32 (4) ◽

pp. 2215-2232 ◽

Cited By ~ 3

Author(s):

Silje Forbord ◽

Sanna Matsson ◽

Guri E. Brodahl ◽

Bodil A. Bluhm ◽

Ole Jacob Broch ◽

...

Keyword(s):

Chemical Composition ◽

Latitudinal Gradient ◽

Biomass Yield ◽

Saccharina Latissima ◽

Seaweed Farming ◽

Membranipora Membranacea ◽

Salinity Levels ◽

Biomass Yields ◽

Tissue Nitrogen ◽

Frond Length

Abstract The Norwegian coastline covers more than 10° in latitude and provides a range in abiotic and biotic conditions for seaweed farming. In this study, we compared the effects of cultivation depth and season on the increase in biomass (frond length and biomass yield), chemical composition (protein, tissue nitrogen, intracellular nitrate and ash content) and biofouling (total cover and species composition) of cultivated Saccharina latissima at nine locations along a latitudinal gradient from 58 to 69° N. The effects of light and temperature on frond length and biofouling were evaluated along with their relevance for selecting optimal cultivation sites. Growth was greater at 1–2 m than at 8–9 m depth and showed large differences among locations, mainly in relation to local salinity levels. Maximum frond lengths varied between 15 and 100 cm, and maximum biomass yields between 0.2 and 14 kg m−2. Timing of maximum frond length and biomass yield varied with latitude, peaking 5 and 8 weeks later in the northern location (69° N) than in the central (63° N) and southern (58° N) locations, respectively. The nitrogen-to-protein conversion factor (averaged across all locations and depths) was 3.8, while protein content varied from 22 to 109 mg g−1 DW, with seasonality and latitude having the largest effect. The onset of biofouling also followed a latitudinal pattern, with a delayed onset in northern locations and at freshwater-influenced sites. The dominant epibiont was the bryozoan Membranipora membranacea. Our results demonstrate the feasibility of S. latissima cultivation along a wide latitudinal gradient in North Atlantic waters and underscore the importance of careful site selection for seaweed aquaculture.

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Gas exchanges in sugar apple (Annona squamosa L.) subjected to salinity stress and nitrogen fertilization

Australian Journal of Crop Science ◽

10.21475/ajcs.19.13.12.p1754 ◽

2019 ◽

pp. 1959-1966

Author(s):

Francisco Romário Andrade Figueiredo ◽

Anderson Carlos de Melo Gonçalves ◽

João Everthon da Silva Ribeiro ◽

Toshik Iarley da Silva ◽

Jackson Silva Nóbrega ◽

...

Keyword(s):

Experimental Design ◽

Gas Exchange ◽

Chlorophyll Content ◽

Irrigation Water ◽

Nitrogen Fertilization ◽

Annona Squamosa ◽

Negative Effects ◽

Chlorophyll Content And Fluorescence ◽

Fluorescence Parameters ◽

Salinity Levels

Salinity is one of the modern agriculture major obstacles, causing several physiological disturbances in plants, adversely affecting its growth and development. Therefore, some techniques are required in order to alleviate the negative effects of salinity stress on plants, as for example an adequate nitrogen fertilization. The aim of this study was to assess the ecophysiological responses of sugar apple plants (Annona squamosa L.) submitted to different salinity levels and nitrogen fertilization doses. The experimental design was a randomized block in an incomplete factorial scheme, with five electrical conductivities of the irrigation water (ECw: 0.5, 1.01, 2.25, 3.49 and 4.0 dS m-1) and five nitrogen doses (0, 101, 350, 598.2 and 700 mg dm-3), with four replicates, generated from the Box Central Composite experimental design matrix. Through a daily course, it was observed variations in gas exchange, chlorophyll content and fluorescence parameters. The gas exchange, chlorophyll content and fluorescence parameters were measured on photosynthetically active leaves. There was significant interaction between the salinity levels (ECw) and nitrogen doses for the chlorophyll indexes. The electrical conductivity of the irrigation water caused significant negative effects on chlorophyll fluorescence. Therefore, it can be stated that the sugar apple plants ecophysiology varies through the day and that salinity affects its chlorophyll content and fluorescence.

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