Cotton shoot plays a major role in mediating senescence induced by potassium deficiency

Hong

Journal of Experimental Botany

et al. 2014

234

237

Section: Introductionmentioning

confidence: 99%

Gene regulatory cascade of senescence-associated NAC transcription factors activated by ETHYLENE-INSENSITIVE2-mediated leaf senescence signalling in Arabidopsis

Hong

Journal of Experimental Botany

et al. 2014

234

237

Journal of Experimental Botany

“…A previous grafting study determined the roles of shoot and root in the regulation of premature leaf senescence induced by K deficiency in cotton (Li et al ., 2012). The results showed that the effect of rootstocks on leaf senescence was significant in some cases, but the scion cultivars explained a higher percentage of variation within grafting treatments.…”

Section: Introductionmentioning

confidence: 99%

“…The results showed that the effect of rootstocks on leaf senescence was significant in some cases, but the scion cultivars explained a higher percentage of variation within grafting treatments. It was speculated that the shoot-to-root feedback signal(s) that mediates xylem phytohormone delivery was involved in the shoot regulation of premature senescence of cotton (Li et al ., 2012). …”

Section: Introductionmentioning

confidence: 99%

“…Therefore, the objectives of this study were to (i) examine the effects of K deficiency on the endogenous ABA, zeatin riboside (ZR) + zeatin (Z), and isopentenyl adenosine (iPA) + isopentenyladenine (iP) levels in roots, leaves, and xylem sap of cotton seedlings; (ii) determine whether there is a linkage between leaf senescence induced by K deficiency and changes in endogenous CK and ABA levels in leaves; and (iii) test the hypothesis that the leaf and xylem CK and ABA levels are dependent on feedback signal(s) derived from the shoot by using a grafting study as in previous work (Li et al ., 2012). The results should aid our understanding of mechanisms of phytohormone involvement in the feedback regulation of leaf senescence induced by K deficiency, and facilitate the development of approaches to managing this problem.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mechanism of phytohormone involvement in feedback regulation of cotton leaf senescence induced by potassium deficiency

Wang

Лі

et al. 2012

127

To elucidate the phytohormonal basis of the feedback regulation of leaf senescence induced by potassium (K) deficiency in cotton (Gossypium hirsutum L.), two cultivars contrasting in sensitivity to K deficiency were self- and reciprocally grafted hypocotyl-to-hypocotyl, using standard grafting (one scion grafted onto one rootstock), Y grafting (two scions grafted onto one rootstock), and inverted Y grafting (one scion grafted onto two rootstocks) at the seedling stage. K deficiency (0.03mM for standard and Y grafting, and 0.01mM for inverted Y grafting) increased the root abscisic acid (ABA) concentration by 1.6- to 3.1-fold and xylem ABA delivery rates by 1.8- to 4.6-fold. The K deficiency also decreased the delivery rates of xylem cytokinins [CKs; including the zeatin riboside (ZR) and isopentenyl adenosine (iPA) type] by 29–65% and leaf CK concentration by 16–57%. The leaf ABA concentration and xylem ABA deliveries were consistently greater in CCRI41 (more sensitive to K deficiency) than in SCRC22 (less sensitive to K deficiency) scions under K deficiency, and ZR- and iPA-type levels were consistently lower in the former than in the latter, irrespective of rootstock cultivar or grafting type, indicating that cotton shoot influences the levels of ABA and CKs in leaves and xylem sap. Because the scions had little influence on phytohormone levels in the roots (rootstocks) of all three types of grafts and rootstock xylem sap (collected below the graft union) of Y and inverted Y grafts, it appears that the site for basipetal feedback signal(s) involved in the regulation of xylem phytohormones is the hypocotyl of cotton seedlings. Also, the target of this feedback signal(s) is more likely to be the changes in xylem phytohormones within tissues of the hypocotyl rather than the export of phytohormones from the roots.

“…Being an important nutritional element, cotton growth, development is dependent on availability of K as it plays an important role in photosynthesis and accumulation and translocation of carbohydrates [3]. Potassium deficiency also influences senescence and physiological metabolism [4].…”

Section: Introductionmentioning

confidence: 99%

Reproductive Performance and Fiber Quality Responses of Cotton to Potassium Nutrition

Lokhande¹,

Reddy²

2015

AJPS

Potassium (K) deficiency affects cotton growth and development and fiber properties. An experiment was conducted in an outdoor pot culture facility by imposing four potassium stress treatments (100%, 40%, 20% and 0% of optimum K level) prior to flowering during 2010 and 2011 growing season. Upland cotton cultivar, TM-1, was seeded in the pots comprised of fine sand as rooting medium. Flowers and bolls were tagged daily to estimate boll maturation period (BMP). Leaf samples were collected every four days from flowering to maturity to estimate leaf K content. Plant height and node numbers were recorded from emergence to 21 days after treatment. Photosynthesis and stomatal conductance were measured weekly from day of treatment imposition to physiological maturity at an interval of seven days. Stem, leaf, and boll dry-component weights, and boll numbers were recorded at the end of the experiment in each year. From each boll, the lint samples were collected and grouped based on average leaf potassium concentration during BMP, and fiber quality parameters were recorded for each group in each treatment. At high K deficient (0 K) condition, total biomass declined by 27% and 28% in years 2010 and 2011, respectively. Significantly, lower numbers of bolls were retained per plant at 0 K stress treatment during both the years. Leaf photosynthesis (r 2 = 0.92) and stomatal conductance (r 2 = 0.80) declined with declining leaf K levels. Fiber length, strength, micronaire, and uniformity declined linearly with decrease in leaf K content. Weaker fibers with medium length were produced under K-deficient conditions with micronaire values in the discount range. Fiber uniformity, however, did not decline with decrease in leaf K. The identified leaf K status-specific relationships for fiber properties could be used to improve management practices under potassium deficiency and to develop new sub-routines of the existing cotton simulation models. New and improved models will be useful not only in management, but also in arena of policy decisions including future climate change impact assessment analysis.