Ectopic overexpression of the cell wall invertase gene CIN1 leads to dehydration avoidance in tomato

Drought stress conditions modify source–sink relations, thereby influencing plant growth, adaptive responses, and consequently crop yield. Invertases are key metabolic enzymes regulating sink activity through the hydrolytic cleavage of sucrose into hexose monomers, thus playing a crucial role in plant growth and development. However, the physiological role of invertases during adaptation to abiotic stress conditions is not yet fully understood. Here it is shown that plant adaptation to drought stress can be markedly improved in tomato (Solanum lycopersicum L.) by overexpression of the cell wall invertase (cwInv) gene CIN1 from Chenopodium rubrum. CIN1 overexpression limited stomatal conductance under normal watering regimes, leading to reduced water consumption during the drought period, while photosynthetic activity was maintained. This caused a strong increase in water use efficiency (up to 50%), markedly improving water stress adaptation through an efficient physiological strategy of dehydration avoidance. Drought stress strongly reduced cwInv activity and induced its proteinaceous inhibitor in the leaves of the wild-type plants. However, the CIN1-overexpressing plants registered 3- to 6-fold higher cwInv activity in all analysed conditions. Surprisingly, the enhanced invertase activity did not result in increased hexose concentrations due to the activation of the metabolic carbohydrate fluxes, as reflected by the maintenance of the activity of key enzymes of primary metabolism and increased levels of sugar-phosphate intermediates under water deprivation. The induced sink metabolism in the leaves explained the maintenance of photosynthetic activity, delayed senescence, and increased source activity under drought stress. Moreover, CIN1 plants also presented a better control of production of reactive oxygen species and sustained membrane protection. Those metabolic changes conferred by CIN1 overexpression were accompanied by increases in the concentrations of the senescence-delaying hormone trans-zeatin and decreases in the senescence-inducing ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) in the leaves. Thus, cwInv critically functions at the integration point of metabolic, hormonal, and stress signals, providing a novel strategy to overcome drought-induced limitations to crop yield, without negatively affecting plant fitness under optimal growth conditions.España Ministerio de Ciencia e Innovación AT2009-0038 and AGL2011-2799

Ectopic overexpression of the cell wall invertase gene CIN1 leads to dehydration avoidance in tomato

Drought stress conditions modify source–sink relations, thereby influencing plant growth, adaptive responses, and consequently crop yield. Invertases are key metabolic enzymes regulating sink activity through the hydrolytic cleavage of sucrose into hexose monomers, thus playing a crucial role in plant growth and development. However, the physiological role of invertases during adaptation to abiotic stress conditions is not yet fully understood. Here it is shown that plant adaptation to drought stress can be markedly improved in tomato (Solanum lycopersicum L.) by overexpression of the cell wall invertase (cwInv) gene CIN1 from Chenopodium rubrum. CIN1 overexpression limited stomatal conductance under normal watering regimes, leading to reduced water consumption during the drought period, while photosynthetic activity was maintained. This caused a strong increase in water use efficiency (up to 50%), markedly improving water stress adaptation through an efficient physiological strategy of dehydration avoidance. Drought stress strongly reduced cwInv activity and induced its proteinaceous inhibitor in the leaves of the wild-type plants. However, the CIN1-overexpressing plants registered 3- to 6-fold higher cwInv activity in all analysed conditions. Surprisingly, the enhanced invertase activity did not result in increased hexose concentrations due to the activation of the metabolic carbohydrate fluxes, as reflected by the maintenance of the activity of key enzymes of primary metabolism and increased levels of sugar-phosphate intermediates under water deprivation. The induced sink metabolism in the leaves explained the maintenance of photosynthetic activity, delayed senescence, and increased source activity under drought stress. Moreover, CIN1 plants also presented a better control of production of reactive oxygen species and sustained membrane protection. Those metabolic changes conferred by CIN1 overexpression were accompanied by increases in the concentrations of the senescence-delaying hormone trans-zeatin and decreases in the senescence-inducing ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) in the leaves. Thus, cwInv critically functions at the integration point of metabolic, hormonal, and stress signals, providing a novel strategy to overcome drought-induced limitations to crop yield, without negatively affecting plant fitness under optimal growth conditions.FPA and co-workers are funded by the Spanish MICINN-FEDER (projects AT2009-0038 and AGL2011-27996) and the European Commission (ROOTOPOWER Contract # 289365). TR and FPA were jointly funded by the Spanish–Austrian bilateral project AT2009-0038. AA was supported by post-doctoral fellowships from the Fundación Séneca (Comunidad Autónoma de la Región de Murcia) and the FWF (Austrian Science Fund), and currently by the JAE DOC Programme

Teaching the numbers to ten to pupils with slight mental developmental disturbances

Darba nosaukums – ‘’Pirmā desmita mācīšana skolēniem ar viegliem garīgās attīstības traucējumiem.” Autore – speciālās izglītības skolotāja profesionālās studiju programmas studente – Laila Jansone. Pētījuma mērķis – izveidot mācību materiālu matemātikā pirmā desmita apguvei jaunākajās klasēs. Teorētiskajā daļā tiek raksturots speciālo skolu skolēnu ar garīgās attīstības traucējumiem izziņas process, mācību organizēšanas īpatnības matemātikas stundās un darbs apvienotajās klasēs bērniem ar garīgās attīstības traucējumiem. Darbs veidots balstoties uz S. Liepiņas, I. Freimaņa, I. Maslo, K. Smitas, E. Krastiņas, J.Menča atziņām, kā arī uz pētījumiem, kas veikti par mācību materiālu veidošanas principiem. Praktiskajā daļā autore veidoja mācību materiālu matemātikā speciālo skolu skolēniem ar garīgās attīstības traucējumiem, kā arī veica aptauju speciālo skolu un vispārējo izglītības iestāžu skolotājiem par mācību līdzekļu daudzveidību pirmā desmita apguvē. Apkopoti un analizēti aptaujas rezultāti. Darbs sastāv no 42 lappusēm, 5 tabulām, 5 attēliem, 67 pielikuma. Darbā izmantoti 26 avoti un literatūra. Atslēgas vārdi – skolēni ar garīgās attīstības traucējumiem, pirmā desmita mācīšanas metodika, mācību materiāls.The theme of the Paper – „Teaching to operate in an amount of ten for students with light mental disturbance.” The authour – the student of Professional Programme – Laila Jansone – of special education. The aim of the research – to create a methodological material in Mathematics for operating in an amount of ten for primary classes. The process of cognition of students with light mental disturbbance in special schools, characteristics of Maths’s lesson organisation and amalgamated work during the lesson for children with light mental disturbance are described in the theoretical part. The Paper is based on S. Liepina, I. Freimanis, I. Maslo, K. Smit’s references and on the researches which have been done concerning principles of creating methodological materials. In the practical part the authour created a methodological material for Maths lessons for students with light mental disturbance. The survey on variety of educational materials concerning operating in an amount of ten was carried out among teachers working in special schools and in general educational establishments. The data was summerized and analysed. The Paper consists of 42 pages, 5 charts, 5 pictures, 00 appendices. 23 literature resources have been applied in the Paper. 1 conference material has been applied, as well. Key words – students with light mental disturbance, methodology of operating in an amount of ten, methodological material