The effect of chilling on photosystem II (PSII) efficiency was studied in the variegated leaves of Calathea makoyana, in order to gain insight into the causes of chilling-induced photoinhibition. Additionally, a relationship was revealed between (chilling) stress and variation in photosynthesis. Chilling treatments (5 degrees C and 10 degrees C) were performed for different durations (1-7 d) un...

A segregating F4 population from the cross between drought sensitive (Yecora Rojo) and drought tolerant (Pavon 76) genotypes was made to identify SRAP markers linked to leaf chlorophyll content, flag leaf senescence and cell membrane stability traits in wheat (Triticum aestivum L.) under water-stressed condition. The parents and 150 F4 families were evaluated phenotypically for drought toleranc...

Chloroplasts were isolated from pea and sunflower leaves having various water potentials. Oxygen evolution by the chloroplasts was measured under identical conditions for all treatments with saturating light and with dichloroindophenol as oxidant. Evolution was inhibited when leaf water potentials were below -12 bars in pea and -8 bars in sunflower and the inhibition was proportional to leaf wa...

Studies dedicated to understanding the behavior of pathogens in relation to their hosts are the starting point for any breeding program aimed to develop resistant cultivars. The objective of this study was to analyze the resistance to Septoria tritici Rob in 77 F11 progenies of wheat derived from the three-way cross Tadinia × (Yecora rojo × UC554) in the phenological stages of seedling, tilleri...

When dhurrin [p-hydroxy-(S)-mandelonitrile-tJ-D-glucoside], the cyanogenic glucoside of sorghum [Sorghum bicolor (L.) Moench], is hydrolyzed by autoclaving, p-hydroxybenzaldehyde (P-HB) is released. The spectrophotometric determination of pHB concentration in autoclaved sorghum leaf extracts provides a measure of the hydrocyanic acid potential (HCN-p) of leaf tissue. Extracts of field-grown sor...

Introduction Proper potassium (K) nutrition is critical for maximizing rice grain yields. K is very mobile within the rice plant. Older leaves are scavenged for the K needed by younger leaves. Recent studies at the Missouri Rice Research Farm have shown that supplemental K can be supplied to the rice plant as late as Internode Elongation (IE) and still increase rice grain yields. In this same s...

Introduction Proper potassium (K) nutrition is critical for maximizing rice grain yields. K is very mobile within the rice plant. Older leaves are scavenged for the K needed by younger leaves. Recent studies at the Missouri Rice Research Farm have shown that supplemental K can be supplied to the rice plant as late as Internode Elongation (IE) and still increase rice grain yields. In this same s...

Paddy soil contaminated by cadmium (Cd) has attracted worldwide attention, while foliar spraying of zinc (Zn) could be considered a cost-effective and practical agronomic measure for reducing Cd accumulation in rice grain. However, the effects due to Zn on different cultivars, as well mechanism subsequent processes taking place are not fully understood up now. To go step ahead, field experiment...

Changes in activities of photosynthetic enzymes and photochemical processes were followed with aging of vegetative and flag leaves of wheat (Triticum aestivum L. cv Roy). Activities of stromal enzymes began to decline prior to photochemical activities. In general, total soluble protein and the activities of ribulose-1,5-bisphosphate carboxylase and NADP-triose-phosphate dehydrogenase declined i...