Study on Soil Improvement Measure of Plant Landscape Construction in Saline and Alkaline Area in Tianjin

A detailed research in soil improving measure was conducted during the process of plants that were cultivated in Tianjin saline and alkaline area. The results showed that the commonly used measures could improve the soil, and also we got some useful advices and suggestions for plants cultivating in Tianiin saline and alkaline areas.

Two-cut system suggested for tall wheatgrass to balance herbage yield and quality in the coastal saline–alkaline land around the Bohai Sea

Background:Tall wheatgrass is a perennial salt-tolerant bunchgrass,which is a promising candidate for establishing a“Coastal Grass Belt”in China,particularly in the coastal saline–alkaline soils surrounding the Bohai Sea.Methods:Seven harvesting treatments were performed to explore the optimal harvesting time and frequency for tall wheatgrass in coastal area.The dry matter yield(DMY)and forage nutritional values were investigated for each cut.The correlation between harvesting time and frequency thereof among the investigated traits was also determined.Results:The results showed that the two-cut on June 18 and October 29 produced the highest DMY.Another two-cut on May 26 and October 29 produced a relatively high crude protein(CP)yield.The DMY,contents of neutral detergent fiber(NDF),acid detergent fiber(ADF),and crude cellulose(CC)as well as CP yield were positively correlated to plant height,while the CP content and the relative feed value(RFV)were negatively correlated to plant height.The accumulating growing degree days,accumulated precipitation,and sunshine duration were positively correlated with plant height,DMY,contents of NDF,ADF,and CC as well as CP yield,but negatively correlated with CP content and RFV for the first cut.Conclusions:The two-cut treatment at the end of May and October may be suitable for tall wheatgrass in the“Coastal Grass Belt”targeted area.

Effects of salinity, carbonate alkalinity, and pH on physiological indicators of nutrition transporter for potential habitat restoration of amphipod Eogammarus possjeticus

The effects of three environmental factors,salinity,carbonate alkalinity,and pH,on the survival,feeding,and respiratory metabolism of Eogammarus possjeticus(Amphipoda:Gammaridae)were investigated experimentally.The results show that E.possjeticus could tolerate a broad salinity range.The 24-h lowest median lethal salinity was 2.70,and the highest was 47.33.The 24-h median lethal alkalinity and pH were 23.05 mmol/L and 9.91,respectively;both values decreased gradually with time.Different values of salinity,carbonate alkalinity,and pH resulted in significant differences in the cumulative mortality(P<0.05).The ingestion rate and feed absorption efficiency were significantly affected by the coupling of the three environmental factors(P<0.05).With increases in carbonate alkalinity,salinity,and pH,both ingestion rate and feed absorption efficiency exhibited a downward trend,indicating a decline in feeding ability under high salinity and more alkaline water conditions.The coupling of salinity,carbonate alkalinity,and pH also had a significant effect on respiration and excretion(P<0.05).The oxygen consumption rate increased first and then decreased with increasing carbonate alkalinity.Under the same carbonate alkalinity values,the oxygen consumption rate increased with increasing salinity.Under the same carbonate alkalinity and salinity,the oxygen consumption rate initially increased and then decreased with increasing pH.The O:N ratio first increased and then decreased with increasing carbonate alkalinity.When carbonate alkalinity was less than 6 mmol/L,the O:N ratio increased with increasing salinity and decreased with increasing pH.The results demonstrate that changes in salinity,carbonate alkalinity,and pH had a measurable impact on the osmotic pressure equilibrium in E.possjeticus and affected the energy supply mode(i.e.ratio of metabolic substrate).

Early Transcriptomic Adaptation to Na_2CO_3 Stress Altered the Expression of a Quarter of the Total Genes in the Maize Genome and Exhibited Shared and Distinctive Profles with NaCl and High pH Stresses

Sodium carbonate （Na2CO3） presents a huge challenge to plants by the combined damaging effects of Na＋, high pH, and CO32. Little is known about the cellular responses to Na2CO3 stress. In this study, the transcriptome of maize （Zea mays L. cv. B73） roots exposed to Na2CO3 stress for 5 h was compared with those of NaCI and NaOH stresses. The expression of 8,319 genes, representing over a quarter of the total number of genes in the maize genome, was altered by Na2CO3 stress, and the downregulated genes （5,232） outnumbered the upregulated genes （3,087）. The effects of Na2CO3 differed from those of NaCI and NaOH, primarily by downregulating different categories of genes. Pathways commonly altered by Na2CO3, NaCI, and NaOH were enriched in phenylpropanoid biosynthesis, oxidation of unsaturated fatty acids, ATP- binding cassette （ABC） transporters, as well as the metabolism of secondary metabolites. Genes for brassinosteroid biosynthesis were specifically upregulated by Na2CO3, while genes involved in ascorbate and aldarate metabolism, protein processing in the endoplasmic reticulum and by N-glycosylation, fatty acid biosynthesis, and the circadian rhythm were downregulated. This work provides the first holistic picture of early transcriptomic adaptation to Na2CO3 stress, and highlights potential molecular pathways that could be manipulated to improve tolerance in maize.