The effect of four rates of nitrogen (N) fertilisation (0, 80, 160, 240 kg ha−1) on the growth and yield components of three winter wheat varieties with different maturity dates (Mv Toborzó — extra early, Mv Palotás — early, Mv Verbunkos — mid-early) was analysed in a long-term experiment laid out in a two-factorial split-plot design with four replications in the years 2007–2009. The dry matter production of the whole plant and of individual plant organs, the maximum leaf area, the area of the flag-leaf and all the yield components except the thousand-kernel weight were significantly the greatest in the N160 or the N240 treatments. Averaged over the varieties and years the grain yield in the N treatments was N0: 5.5, N80: 7.1, N160: 7.3 and N240: 7.5 t ha−1. Averaged over N treatments and years the variety Mv Verbunkos had the highest dry matter production, stem mass, spike mass, number of grains per spike and grain yield. Mv Verbunkos had the greatest leaf area in the favourable years of 2008 and 2009 and the greatest flag-leaf area in 2008. Averaged over N treatments and varieties the dry matter production per plant, the leaf and stem mass, the number of spikes per square metre and the thousand-kernel weight were greatest in 2007. The spike mass was lowest in 2007 and had higher, very similar values in 2008 and 2009. The maximum leaf area per plant, the area of the flag-leaf, the number of grains per spike and the grain yield were highest in 2008. The values and dynamics of the growth parameters gave a good characterisation of the effect of the treatments (N fertilisation, variety, year) on plant production (yield, yield components) in various stages of growth.
Authors:Y.G. Shi, Y. Lian, H.W. Shi, S.G. Wang, H. Fan, D.Z. Sun, and R.L. Jing
Senescence in a wheat (Triticum aestivum L.) leaf is a programmed degeneration process leading to death. During this process, green leaf area duration (GLAD) and green leaf number of main stem (GLNMS) are gradually reduced. In this study, the two traits of Hanxuan10/Lumai14 DH population at different development stages after anthesis were evaluated under rainfed and irrigated conditions, and QTLs were detected. GLAD and GLNMS of two parents and DH population under rainfed condition were less than those under irrigated condition, and close correlations (P < 0 05) were found between GLAD and GLNMS after 25 DAA under both water conditions. GLAD and GLNMS were co-controlled by major and minor genes. QTLs for GLAD were stably expressed at different development stages after anthesis under both water conditions, such as QGlad22-1B-1, QGlad25-1B-1, QGlad28-1B-2 detected under irrigated condition and QGlad25-1B-3, QGlad28-1B-4 mapped under rainfed condition were located at a 20.7 cM marker interval of Xgwm273-EST122 on 1B chromosome. But QTLs for GLNMS were inducibly and specifically expressed at specific developmental stages after anthesis under both water conditions. The findings provide dynamic genetic information related to wheat senescence.
The functional-trait approach to communities focuses on the distribution of traits and on their variations in communities along environmental gradients. We devised a pattern-oriented demarche to predict specific leaf area (SLA) distribution in three plant communities located along an environmental gradient governed by soil fertility and nutrient stress in subalpine gypsic dolines. An individual-based model incorporating physiological mechanisms simulated the growth of thirty functional groups varying in leaf traits (SLA and correlated leaf life-span) and nitrogen (N) stress tolerance which competed with their neighbours for access to light and nitrogen. The SLAs of these groups encompassed the range of SLAs measured in the sites. Leaf traits governed the daily temperature-dependent processes involved in capturing resources (N and light), biomass synthesis and loss, and the value of the parameter Nc governed the decrease in growth rate of organisms according to a decline in N supply. Biomass drove the competitive ability of each plant in its neighbourhood. A soil sub-model described the amount of available nitrogen in the soil. Simulations yielded performances of functional groups according to the availability of nitrogen in the soil. An integration function, which simulated the effects of the dominance process according to the performances of the groups, yielded the frequency distribution of the groups at the community scale. The SLAs patterns were deduced from this distribution. Comparison of simulated and measured distribution of SLA frequency (Kendall tests) showed the model’s ability to reproduce realistically SLA distributions along a nutrient gradient; measured SLA community patterns at lower, medium and higher fertility levels matched simulated SLA distribution with respectively 5 to 30, 82, and 154 kg N ha−1 year−1. These results demonstrate the efficacy of a strategy based on a pattern-oriented approach and the use of functional traits and trade-offs to predict the distributions of traits and their variations in communities along an environmental gradient.
Authors:K. Bharti, N. Pandey, D. Shankhdhar, P.C. Srivastava, and S.C. Shankhdhar
A two-year field experiment was conducted to study the effect of three zinc levels 0, 20 kg ZnSO4 ha−1 and 20 kg ZnSO4 ha−1 + foliar spray of 0.5% ZnSO4 solution on plant height, leaf area, shoot biomass, photosynthetic rate and chlorophyll content in different wheat genotypes. Increasing zinc levels was found to be beneficial in improving growth and physiological aspects of genotypes. Soil application + foliar spray proved to be the best application in improving all the parameters. Zinc application brought about a maximum increment limit of 41.8% in plant height, 101.8% in leaf area, 86% in shoot biomass and 51.1% in photosynthetic rate irrespective of stages and year of study. A variation was found to occur among genotypes in showing responses towards zinc application and PBW 550 was found to be more responsive.
Wheat is the second most important crop after rice in India and occupies approximately 28.5 million hectare area. Salinity is one of the major factors reducing plant growth and productivity worldwide, and affects about 7% of world’s total land area. In India about 6.73 million hectare land area is salt affected. The aim of this study was to investigate the morpho- physiological and biochemical response of wheat to temporal salinity (ECiw = 10.0 dSm–1) exposures. Ten wheat genotypes were evaluated in two successive growing seasons (2012–2014), with complete randomized design with three replications under both salinity stress and non-stress conditions. The morpho-physiological and biochemical character measured in this investigation, inhibited under both salt stresses (S1 & S2) conditions but much more significantly inhibited under long-term salinity exposure (S2) than S1 because interrupting the metabolic process of plant, resulting in reduced growth and productivity. According to correlation result, selection of high yield genotypes can be done based on plant height (0.649*), tiller plant–1 (0.808**) and leaf area (0.687*). The multivariate morphophysiological and biochemical parameters should be further used to develop salinity tolerance in wheat breeding improvement programmes.
The low seedling vigour of Russian wildrye grass (
) (RWR) limits its use. Shading from durum wheat (
) reduced RWR leaf number, tiller number, leaf area and seedling dry weight in a growth room experiment. Treatments with similar shading differed in tiller number and dry weight, which suggested that light quality may have also contributed to these responses. In a second growth room experiment, light intensity (PAR) and red:far-red light ratio (670:730 nm) were altered by coloured plastic filters suspended above seedlings of Russian wildrye, crested wheatgrass (
) (CWG) and Dahurian wildrye grass (
) (DWR). Leaf area, tiller number and dry weight of RWR seedlings were reduced by declining red:far-red light ratio while light intensity differences at similar red:far-red ratio did not affect these variables. CWG exhibited similar responses to declining red:far-red light ratio as RWR, except that it exhibited a seedling weight response to light intensity. DWR tiller number was not responsive to low red:far-red light ratio but rather to low light intensity. However, DWR seedling weight, tiller weight and leaf area were responsive to declining red:far-red light ratio. These results indicate that RWR seedlings are sensitive to light quality changes caused by neighbouring plants.
The long-term protection of plant species is impossible without a comprehensive and thorough knowledge of their biology. This paper deals with some of the important aspects of the biology of two strictly protected species,
The changes of the leaf area of plants were measured with a non-destructive method and the growth pattern was investigated during the vegetation period. It was also studied how the plant size of individuals changed from year to year, and what kind of connection there was between the plant condition and the flowering. Large size plants of both species were characterised by intensive growth rates in autumn and spring, their growth stopped in winter. Often they lost some of their leaf areas because of damage from insects (mainly in the case of
, and frost (almost exclusively in the case of
). In some years the medium and small size plants were characterised by similar growth pattern to those of large size ones, but more often their growth did not stop in winter, though their growth was not so fast. The medium and small size
individuals showed an intense autumn growth only in one vegetation period, which characterised both large size individuals of
and all individuals of
The constant annual rate of growth, which may have been slowed meaning that the leaf number did not grow, but it did not stop either, was detected in hardly more than 10% of individuals with both species. In the case of
the critical size for flowering seemed to be 50 cm
, which was usually reached in the four-leaf stage of the rosettes. The same value was 100 cm
in the case of
and it needed at least a six-leaf basal rosette. The leaf number and the leaf area of reproductive plants had been larger for already two years before flowering took place, than those of the plants that remained vegetative.
Authors:M. M. Azooz, M. A. Shaddad, and A. A. Abdel-Latef
The salt tolerance of three sorghum (Sorghum bicolor L.) cultivars (Dorado, Hagen Shandawil and Giza 113) and their responses to shoot spraying with 25 ppm IAA were studied. Salinity stress induced substantial differences between the three sorghum cultivars in the leaf area, dry mass, relative water content and tolerance index of the leaves. Dorado and Hagen Shandawil tolerated salinity up to 88 and 44 mM NaCl, respectively, but above this level, and at all salinity levels in Giza 113, a significant reduction in these parameters was recorded. The rate of reduction was lower in Dorado than in Hagen Shandawil and Giza 113, allowing the sequence Dorado ? Hagen Shandawil ? Giza 113 to be established for the tolerance of these cultivars to salinity. The differences in the tolerance of the sorghum cultivars were associated with large differences in K+ rather than in Na+, which was found to be similar in the whole plant. The youngest leaf was able to maintain a higher K+ content than the oldest leaf. Consequently the K+/Na+ ratios were higher in the most salt-tolerant cultivar Dorado than in the other sorghum cultivars, and in the youngest than in the oldest leaf. In conformity with this mechanism, the stimulatory effect of the exogenous application of IAA was mostly associated with a higher K+/Na+ ratio. Shoot spraying with IAA partially alleviated the inhibitory effect of salinity on leaf growth and on the K+ and Ca2+ contents, especially at low and moderate levels of salinity, while it markedly retarded the accumulation of Na+ in the different organs of sorghum cultivars. Abbreviations: LA: Leaf area, DM: Dry mass, I Indole acetic acid, RWC: Relative water content,TI: Tolerance index