Evidence for age- and size-mediated controls of tree growth from grafting studies     

Mencuccini M  Martínez-Vilalta J  Hamid HA  Korakaki E  Vanderklein D 《Tree physiology》2007,27(3):463-473

Vegetative propagation techniques such as grafting can be used, in conjunction with field studies, to decouple the relative effects of age and size on tree metabolism and growth. Despite interest in this approach, little attention has been paid to the best metrics for assessing the growth performance of grafted plants over time. Based on an analysis of the grafting literature and our own data, we show that the choice of metrics to assess tree growth can entirely change the conclusions reached about the relative importance of age versus size. We recommend that absolute as well as relative rates of growth are calculated and that scion size be standardized as much as possible at the start of the experiment. Once proper metrics are chosen, all of the available published evidence is largely concordant with two concepts: (1) age-mediated controls of tree growth are likely to be important during the first few years of a tree's life (before phase change); and (2) after the first few years of a tree's life, size-mediated factors largely prevail over age-mediated factors in determining tree growth rates. We found no support for theories invoking age-mediated sink limitations in old trees.  相似文献   

Effect of drought stress on root yield and some morpho-physiological traits in different genotypes of sugar beet (<Emphasis Type="Italic">Beta vulgaris</Emphasis> L.)     

Seyyed Gholam Reza Moosavi  Seyyed Hamid Reza Ramazani  Saeid Sadeghzadeh Hemayati  Hamid Gholizade 《Journal of Crop Science and Biotechnology》2017,20(3):167-174

To study the effects of different levels of drought stress on root yield and some morpho-physiological traits of sugar beet genotypes, a study was conducted in the research farm of Islamic Azad University of Birjand, Iran in 2013 as strip-split plot experiments based on randomized complete block design. Different levels of drought stress were considered as vertical factor in three levels including normal irrigation, moderate stress, and severe stress. Horizontal factor was assigned to five varieties of sugar beet. Drought stress had a significant effect on root dry weight, total dry weight, root yield, and leaf temperature at 1% probability level and on leaf dry weight, crown dry weight, and harvest index at 5% probability level. Drought stress had an adverse effect on root yield of investigated genotypes of sugar beet. Under normal conditions, the mean of root yield was higher than middle and severe drought stress. Different investigated genotypes of sugar beet responded to drought stress based on their yield potential. The highest positive correlation of root yield was observed with root dry weight (r=0.977**). Stepwise regression analysis and path coefficient analysis showed that root dry weight and petiole dry weight are the most important traits that can affect root yield of sugar beet under drought stress and can used as selection criteria in investigated cultivars of sugar beet. Finally, 7221 genotypes can be considered as tolerant genotypes in the next studies. In comparison, Jolgeh cultivar (as susceptible control) yielded well in areas with normal irrigation, but under moderate and severely stresses its root yield was reduced.  相似文献   

Assessment of social sustainability components in agriculture sector of Iran using a systemic approach     

Ghadermarzi  Hamed  Ataei  Pouria  Karimi  Hamid  Safaei  Safe Allah 《Paddy and Water Environment》2020,18(3):547-559

  相似文献   

Erratum to: Wild pistachio tree (Pistacia mutica) in the Qalajeh forest region of western Iran     

Mohsen Javanmiri Pour  Mousa Rasouli  Hamid Soofi Mariv  Mohammad Avatefi Hemat  Masood Shahmoradi 《林业研究》2014,25(2):487-487

<正>Erratum to:Journal of Forestry Reasearch,(2013)24(3):611-614DOI10.1007/s11676-013-0393-2The original version of this article unfortunately contained one mistake in author name in the footnote.The second author's name,"Mousa Rasouli",actually should be Hamid Soofi Mariv.The corrected version of the footnote should be as the following:  相似文献   

Assessment of Phosphorus Levels in Small Ruminants as Affected by Summer and Winter     

Ansar Mahmood  Dr.Asma Hassan  Iram Maqsood  Tang Li-jie  Syed Mohsin Bukhari  Khalil-Ur-Rehman  and Shahla Andleeb 《东北农业大学学报(英文版)》2014,21(1):45-51

An experiment was carried out to assess the phosphorus status of free grazing goats at Faisalabad,Pakistan.Samples were collected fortnightly during summer and winter seasons of 2010 from soil and plants.The highest(118±0.54 mg·kg-1)levels of feces phosphorus were recorded in lactating goats during winter and(9.87±0.99 mg·kg-1)in urine of male during winter.Similarly maximum(71.0±0.88 mg·kg-1)phosphorus concentration was observed in the plasma of lactating animals.Milk contained(31.0±0.36)mg·L-1 in winter while during the months of summer the highest values recorded in forages,soils,canal and tube well waters were(755±1.98)mg·kg-1,(785±4.98)mg·kg-1,(0.97±8.78)mg·L-1 and(4.12±0.55)mg·L-1,respectively.It was revealed from the current results that fecal matter,forage,milk,tube well and canal water contained lower amounts of P,while P levels in blood plasma was found within the critical limits.Therefore,phosphorus supplementations were required in the area under experimentation to meet the requirements of the animals for their normal growth.  相似文献   

Measuring crop status using multivariate analysis of hyperspectral field reflectance with application to disease severity and plant density   总被引：1，自引：0，他引：1  

A. Larsolle  H. Hamid Muhammed 《Precision Agriculture》2007,8(1-2):37-47

Using spectral reflectance to estimate crop status is a method suitable for developing sensors for site-specific agricultural applications. When developing spectral analysis methods, it is important to know the influence of different crop parameters on the spectral reflectance profile. The objective of this report was to present and evaluate a multivariate method for objective hyperspectral analysis in the examination of how different parts of the reflectance spectrum are affected by disease severity and above ground plant density. Data from two field experiments were used; fungal disease severity assessments in wheat 1998 and above ground plant density measurements 2003. The analysis method consisted of two steps: a pre-processing step where the data was normalized and a classification step for estimating the crop variable. Using only 12% of the data as training data, the method resulted in coefficients of determination (R ²) of 94.3% for the disease severity data and 96.9% for the plant density data. The hyperspectral analysis method presented could also be used to extract spectral signatures of disease severity and plant density using the experimental data. In general, two types of spectral signatures for both data sets, with respect to increasing disease severity and decreasing plant density, were observed (1) a flattening of the green reflectance peak together with a general decrease in reflectance in the near infrared region and, (2) a decrease of the shoulder of the near infrared reflectance plateau together with a general increase in the visible region between 550 and 750 nm.  相似文献   

A genomic regulatory network for development     

Davidson EH  Rast JP  Oliveri P  Ransick A  Calestani C  Yuh CH  Minokawa T  Amore G  Hinman V  Arenas-Mena C  Otim O  Brown CT  Livi CB  Lee PY  Revilla R  Rust AG  Pan Zj  Schilstra MJ  Clarke PJ  Arnone MI  Rowen L  Cameron RA  McClay DR  Hood L  Bolouri H 《Science (New York, N.Y.)》2002,295(5560):1669-1678

Development of the body plan is controlled by large networks of regulatory genes. A gene regulatory network that controls the specification of endoderm and mesoderm in the sea urchin embryo is summarized here. The network was derived from large-scale perturbation analyses, in combination with computational methodologies, genomic data, cis-regulatory analysis, and molecular embryology. The network contains over 40 genes at present, and each node can be directly verified at the DNA sequence level by cis-regulatory analysis. Its architecture reveals specific and general aspects of development, such as how given cells generate their ordained fates in the embryo and why the process moves inexorably forward in developmental time.  相似文献   

Comparison of different soilless media for growing gerbera under alkalinity stress condition     

Hamid R. Roosta  Meysam Manzari Tavakkoli  Mohsen Hamidpour 《Journal of plant nutrition》2016,39(8):1063-1073

A factorial experiment was developed with two factors of the growing medium (v/v): 100% coconut fiber (CF), 75% vermicompost+25% perlite (VP), 25% zeolite+75% perlite (ZP), 75% peat+25% perlite (PP), 75% coco chip+25% perlite (CCP), 75% coconut fiber+25% perlite (CFP) and 100% perlite (P); and sodium bicarbonate (NaHCO₃) (0, 20 and 40 mM) involving the growth of gerbera cv. Dafne. Compared with CF substrate, NaHCO₃ in the nutrient solution caused significant decrease in vegetative and reproductive traits and nutrient concentration [especially iron, phosphorus, and magnesium (Fe, P and Mg)] in the rest of the media. The improved crop performance of plants grown onto CF substrate was attributed to their strong capacity to accumulate Fe in the aerial part under alkaline conditions and to maintain a better plant nutritional status (higher P and Mg). It is concluded that the use of CF substrate could provide a useful tool to improve alkalinity tolerance of gerbera plants under NaHCO₃ stress.  相似文献   

Rhizosphere effects on Cu availability and fractionation in sewage sludge‐amended calcareous soils          下载免费PDF全文

Hamid Reza Motaghian  Ali Reza Hosseinpur 《植物养料与土壤学杂志》2015,178(5):713-721

Rhizosphere processes have a major impact on copper (Cu) availability and its fractions in soils. A greenhouse experiment with wheat was performed to investigate availability (using seven chemical procedures) and fractionation of Cu in the rhizosphere of ten agricultural soils (Typic Calcixerepts) amended with sewage sludge (1% w/w) using rhizoboxes. The results show that available Cu concentrations in rhizosphere soils were significantly (P < 1%) lower than in bulk soils. In comparison with the bulk soils, in the rhizosphere soils the concentration of Cu associated with organic matter and residual Cu increased by 24 and 4%, respectively, whereas exchangeable Cu, Cu associated with iron‐manganese oxides, and Cu associated with carbonate decreased by 20, 14, and 12%, respectively. Dissolved organic carbon (DOC) and Cu associated with iron‐manganese oxides and Cu associated with organic matter in the rhizosphere and bulk soils were significantly correlated (P < 5%). The results show that the differences between rhizosphere and bulk soils in chemical conditions such as DOC concentrations can change the proportion of soil Cu fractions and, therefore, Cu availability for wheat in calcareous soils amended with sewage sludge. The results show that the wheat root‐induced modifications of chemical and biological soil conditions do not only lead to Cu depletion in mobile soil Cu fractions, but also to modification in soil Cu fractions which are commonly considered as more stable.  相似文献   

伊犁河谷土壤含盐量空间变异和格局分析   总被引：4，自引：0，他引：4  

古丽娜尔·托合提  海米提·依米提  米日姑·买买提  祖皮艳木·买买提 《干旱地区农业研究》2011,29(2):152-158

基于区域变量理论,在GPS和GIS技术支持下,通过地统计学的半变异函数和Kriging空间插值,以察布查尔县为例,定量分析伊犁河谷不同层次土壤盐分的空间异质性.结果表明:0～20 cm、20～40 cm、60～80 cm层土壤盐分的半变异函数符合球状模型,40～60 cm层符合高斯模型.不同层次土壤盐分之间的空间自相关...  相似文献