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MADS-domain proteins are important transcription factors involved in many biological processes of plants. In our study, a tomato MADS-box gene, SlFYFL, was isolated. SlFYFL is expressed in all tissues of tomato and significantly higher in mature leave, fruit of different stages, AZ (abscission zone) and sepal. Delayed leaf senescence and fruit ripening, increased storability and longer sepals were observed in 35S:FYFL tomato. The accumulation of carotenoid was reduced, and ethylene content, ethylene biosynthetic and responsive genes were down-regulated in 35S:FYFL fruits. Abscission zone (AZ) did not form normally and abscission zone development related genes were declined in AZs of 35S:FYFL plants. Yeast two-hybrid assay revealed that SlFYFL protein could interact with SlMADS-RIN, SlMADS1 and SlJOINTLESS, respectively. These results suggest that overexpression of SlFYFL regulate fruit ripening and development of AZ via interactions with the ripening and abscission zone-related MADS box proteins. [ABSTRACT FROM AUTHOR]

In order to explore the changes in antioxidant metabolism related to leaf senescence under potassium (K) deficiency, field experiments were conducted in 2012 and 2013 with contrasting two cotton ( Gossypium hirsutum L.) cultivars in low-K sensitivity (Simian 3, low-K tolerant and Siza 3, low-K sensitive) under three K levels (0, 150 and 300 kg K 2 O ha −1 ). Results showed that K deficiency enhanced the early season flowering rate, earliness, shedding rate and yellow leaf rate, and decreased leaf number, leaf area, boll number, seed cotton weight per boll and lint percentage. The premature senescence of leaf subtending the cotton boll (LSCB) induced by K deficiency was characterized by early chlorophyll degradation and negative chlorophyll fluorescence. Despite higher activity of hydrogen peroxide (H 2 O 2 ) scavenging enzymes (catalase and peroxidase) and higher content of ascorbic acid (ASC) existed in the K-deficient leaf, higher H 2 O 2 content was observed, which caused higher malondialdehyde content. Although lower dehydroascorbate reductase activity was observed under K deficiency, high ASC content was attributed to lower ascorbate peroxidase activity. The differences between Siza 3 and Simian 3 in response to K deficiency were that: (1) the seed cotton weight per boll and lint percentage in Siza 3 decreased more obviously, (2) higher leaf K concentration was needed for maintaining chlorophyll content for Siza 3, (3) Chlorophyll fluorescence parameters was more easily damaged in Siza 3, especially non-photochemical quenching, and (4) superoxide dismutase and glutathione reductase activities decreased markedly only in Siza 3. [ABSTRACT FROM AUTHOR]

• Soil water age is related to soil depth. • The water age of plant xylem and root zone soil is similar. • MTTs in a wet year are shorter than in a normal year. • The TTDs of some hydrological components vary between two hydrologic years. Transit times and the young water fraction (F yw , the proportion of the water younger than a certain age threshold, τ yw) can help characterize the hydrological behaviors within a catchment. Previous studies of water age have concentrated on individual catchment hydrological components, such as river water, groundwater, plant water or soil water, which hinders the dynamic linking of various hydrological components in the critical zone. In this study, the isotopic compositions of precipitation, soil water, xylem water, river water, and groundwater in a subtropical catchment in China were continuously monitored for two years. We found that the seasonal isotopic cycles of shallow soil water (0–60 cm), xylem water and river water had different attenuations and phase shifts relative to those of precipitation. There were no obvious seasonal isotopic cycles of deep soil water (60–130 cm) and groundwater. Additionally, the transit time distributions (TTDs) of soil water at the depth of 0–10 cm, xylem water and river water in the catchment varied between the wet year and normal year. With increasing depth, the mean transit times (MTTs) of soil water increased and the F yw decreased. For xylem water and soil water, the MTTs and F yw in the wet year were shorter and larger than those in the normal year, respectively. The river water consisted of a small proportion of fast flow components and a large proportion of slow flow components, with the young water accounting for 16% in the wet year and 21% in the normal year. Our results contribute to an improved understanding of water ages, flow paths and linkages of different hydrological components in the critical zone at the catchment scale. [ABSTRACT FROM AUTHOR]