Chemical and biochemical changes of pumpkin (Cucumis moschata, Duch) tissue in relation to osmotic stress

Abstract

Chemical and biochemical changes of pumpkin (Cucumis moschata, Duch) tissue in relation to osmotic stress were studied and related to tissue textural behavior. Turgor pressure of raw tissue was adjusted by immersion in hypotonic (0.0 mol m −3 ), isotonic (250 mol m −3 ) and plasmolyzing (1050 mol m −3 ) buffered (20 mol m −3 potassium phosphate, pH 6.8) solutions of poly(ethylene glycol) 400 (PEG). It was found that a substantial proportion of polysaccharides located in the cell wall (CW)-middle lamellae (ML) of studied tissue was water extractable. This proportion decreased when CW-stretch increased. Ionically bound peroxidase (POX) presented an increased activity in swollen and isotonic tissue, probably associated to oxidative cross-linking of extensin located in the CW of this tissue, as a response to stress promoted by cut, immersion and turgor pressure change. The resistance of CW to elongation when equilibrated in hypotonic medium, might be ascribed to reinforcement of the CW by the oxidative cross-linking of extensin, with simultaneous formation of pectin-in-extensin entanglements. Plasmolyzed tissue where CW is relaxed, showed pectin-rhamnogalacturonan degradation. The water-soluble fraction (WSF) was shown to be a negative function of CW stretching and infinite force of relaxation.

Investigation on the relationship of proline with wheat anti-drought under soil water deficits

“…Our results demonstrated that Pro content (Figs. 1-5) was a better indice for evaluating wheat drought resistance [11,18,47,71,74]. Finally, our results primarily showed that genotypes 5, 9 and 10 were potential wheat genotypes for popularizing in arid and semiarid locations.…”

“…1 and 2) is tightly linked with the location of their cultivation, which reflects the change of corresponding alleles of different genotypes under the pressure of natural and artificial selection [7,17,35,47]. Moreover, this might be linked with evolution of wheat root systems [8,38,39,41,47,[68][69][70][71][72]. This point is of importance to plant species selection for eco-environmental construction and crop selection for agricultural sustainable development in arid and semi-arid regions.…”

“…It has been well known that osmotic regulators include many important small molecules such as potassium, soluble sugar, proline and betaine [2,5,6,21,25,34,42,52,64,67,70,74,75,77]. These small molecules are also important physiological indicators for evaluating osmotic adjustment ability [62][63][64][65][66][67][71][72][73][82][83][84] and drought resistance in wheat species and genotypes. To aim at making different wheat genotypes perform fully physiological potential under limited soil water conditions in fields, by selecting practical materials for direct breeding and establishing an efficient platform for deciphering molecular mechanisms of wheat drought resistance, we chose 10 promising wheat genotypes (field experiments have proved) as experimental materials, applied stimulation natural drought and potting cultivation methods, collected proline data of two growth stages (seedling stage and tillering stage) and primarily evaluated the relationship between their anti-drought and these genotypes and proline.…”

Pumpkin (Cucurbita moschata Duchesne ex Poiret) mesocarp tissue as a food matrix for supplying iron in a food product

“…As previously stated, Cucurbita moschata has neither lignin nor phenolic compounds (de Escalada Pla et al, 2005) that can impair iron bioavailability. In the last years, some studies have demonstrated that vitamin A and, even more, b-carotene significantly increase iron bioavailability.…”

“…In a previous paper (de Escalada Pla et al, 2005) the composition of this kind of pumpkin was studied and neither lignin nor phenolic compounds that can inhibit iron absorption were found, a fact that allows one to consider this matrix as potentially interesting for fortification. Consequently, the aim of this work was to evaluate the performance of pumpkin (Cucurbita moschata, Duchesne ex.…”