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Boron (B) is an essential microelement for growth and development of higher plants, and is one of the most sensitive crops to B deficiency. In China, there are more than 6.67 million hectares of oil rapeseed distributed mainly in East, Middle and Down Stream valley of Yangtze River, and Southwest, which are deficient or seriously deficient in available B (Liu 1996). grown in these areas usually shows B-deficiency symptoms or at least yield depression without application of B fertilizer. However, there are significant differences between cultivars in their response to B-deficiency (James et al. 2000a, b, 2001; Hu et al. 1991, Yuan and Liu 1990, Xie and Yang 1994, Xie et al.1994). Thus, it is possible that screening for B-efficient germplasm of can serve to breed for cultivars better adapted to soils low in available B.

India has largest area under mango in the world at 1.1 m ha and it is also the fruit crop cultivated in largest area in Inda but its average productivity is lowat 6-8t ha year. It is considered as a hardy crop and hence is grown under rainfed situation with low input management and is also less profitable compared to many other fruit crops. Among the reason for its low productivity and profitability, altenrnate year bearing or orregular bearing is the major one (Yadav1997). Out of 15-20 important commercial cultivars only Neelum, Mallika and Totapuri are considered regular bearers (RB) but their market acceptibility is limited. Premium and profitable cultivars like Alphonso, banganapalli prefered in lopcal and export markets are alternate bearers (AB) and farmers are at a disadvantage. Since B deficiency (Fig.1) is considered as one of the important causes of low productivity and quality problems (Edward M. Raja, 2005) it was decided to investigate whether inability to tolerate B deficiency could be a cause for alternate bearing. Scott (1952) observed cultivar differences in B deficiency tolerance in grapes grown in same field. Out of 44 cultivars evaluated only 14 were severely affected 12 were not affected. B susceptible cultivars when grafted on various rootstocks did not show any B deficiency symptomes. Fe efficiency in Mngo rootstock has been used in Israel (Kadman and Gazit 1976). The mechanisms of tolerance are as follows: Low metabolic requirement, root Geometry and their distribution in different horizon, and translocation of B fromroot to shoot through xylem and movement from old leaves or shoot to young roots through phloem (Graham 1984). Though B is generally phloem immobile, some members of the Apple have ability to translocation by carbohydrate derivatives like sorbital (Brown and Hu 1996). Wall and Andus (1962) indicated that the T3238 tomato mutant is susceptible to B deficiency because it lacks the ability to transport b to the top of the plant. According to Kelly and Gavelman (1962) Ca and K levels and Ca/B ratio decides the B nutrition and not the total Bconcentration. Hence this study was initiated to study thye factors governing the defferential tolerance of regular and alternate bearing mango cultivars to B deficiency.

Previous research showed that the amount of boron (B) required for root growth in a B-inefficient rape cultivar was higher than that in a B-efficient cultivar, which caused a rapid inhibition of root growth in the B-efficient cultivar when it suffered B deficiency (Hu et al. 1994; Cao et al. 1996; Xiong et al. 1995). The typical symptom of B deficiency is inhibition of root tip growth caused by the disruptions of structure and elasticity of cell walls (Hu and Brown 1994). The composition and properties of pectin may play a critical role in determining the physical characteristics of the cell wall (Jarvis 1984). Boron is bound to pectin in cell walls by the formation of borate-ester cross-links with pectin which affects colloidal state and properties of pectin and the elasticity of cell wall (Hu et al. 1996). While differences in B requirements among species were known to correlate with differences in pectin content of cell walls, it is not know if differences in cell wall composition can explain known cultivar differences in B efficiency. The objective of this study was to elucidate mechanism of B efficiency in B-efficient and B-inefficient rape cultivars by examining wall composition, with particular emphasis on pectin.

The maize ( L.) (2n=20) is one of the most widely grown staple plants of the world, ranking first followed by the rice and the wheat. Considerable increases in production and acreage were achieved in all over the world during the last quarter of the 20th century. The production of maize in Turkey has also increased steadily during the last decade (FAOSTAT). Central Anatolian Region has been traditionally considered as the cool season cereals (mainly wheat and barley) storehouse of Turkey with a production of about 4 million tones from 3.5 million ha acreages. Although maize has only recently been introduced to the region, it has been well accepted by the farmers as a valuable alternative crop to sugar beet which requires a compulsory 4 years crop rotation. It is expected that maize cultivation may expand to 100 000 ha in the coming years due to increasing demand for food and animal feed. Now, hybrid maize is the leading type of maize grown on most farms.

Boron has served essential function since the early evolution of life as evidenced by the essentiality of the element for the heterocystous Cyanobacteria, predominant organisms during the Middle Pre-Cambrian Period (Bonilla et al. 1990). The element boron is essential for at least some organisms in all phylogenetic kingdoms. The first natural biomolecules found to contain boron were antibiotics produced by species in Eubacteria (Bonilla et al. 1990; Chen et al. 1981; Hutter et al. 1967; Sato et al. 1978; Schummer et al. 1994). Boron is required for specific brown algae and diatoms in Stramenopila and for all higher plants in Viridiplantae (Lovatt and Dugger 1984). Specific fungi have a demonstrated physiological response to boron (Bennett et al. 1999), an important finding because species in the kingdom Fungi are thought to share a common ancestor with animals exclusive of plants (Carney and Bowen 2004). This review summarizes the evidence that boron satisfies the criteria for essentiality in humans and higher animals (Expert Consultation WHO/FAO/IAEA 1996; Frieden 1984; Mertz 1970; Underwood and Mertz 1987): 1) it reacts with biological material or forms chelates; 2) it is present in healthy tissues of different animals at comparable concentrations; 3) toxicity results only at relatively high intakes; 4) tissue concentrations during short term variations in intake are maintained by homeostatic mechanisms; 5) depletion prevents growth and completion of the life cycle; 6) depletion consistently results in reduction of a physiologically important function; and 7) when an integral part of an organic structure, depletion causes reduction in performance of a vital function.

Research in a number of animal species indicates that boron is of nutritional importance and findings continue to support the concept that boron is an essential trace element (Nielsen, 2002). Recent studies indicate that dietary boron affects various immune processes (Hunt and Idso, 1999; Armstrong et al. 2001). The immune system consists of an array of interrelated components that function to protect the host animal against foreign materials, including pathogenic organisms. The immune system can be divided into innate and adaptive or acquired immunity. Innate immunity is non-specific in regard to foreign organisms that it will attack, and consists of physical barriers to organisms such as skin and internal mucous membranes, as well as components that are induced by exposure to foreign material such as phagocytic cells and complement. The innate immune system responds rapidly to invasion of the host by foreign materials; however, its effect is of relatively short duration. The adaptive immune system develops slower in response to attack by various invaders, but is more substained and leads to proliferation of lymphocytes and synthesis of antibodies specifically directed at the organism invading the host. In addition, the adaptive immune system also results in immunological memory that provides long-term immunity against future attacks by the same organism. This paper will review research indicating a role for boron in immune function.

Studies by several different research groups using different experimental animals indicate that nutritional amounts of boron beneficially affect bone histomorphological and gross physical characteristics. One of the first studies suggesting that boron is essential for higher animals found that boron improved bone calcification in chicks fed a diet deficient but not completely lacking in vitamin D (Hunt and Nielsen, 1981). At the microscopic level, boron deprivation (0.465 mg/kg diet) exacerbated the distortion of marrow sprouts (location of calcified scaffold erosion and new bone formation) and the delay in initiation of cartilage calcification in bones during marginal vitamin D deficiency (Hunt, 1996).

The aim of this paper is describe how boron was identified as an anticancer agent for prostate cancer and how research using human prostate cells identified a biochemical mechanism that may explain many of the diverse effects reported for the element in plants and animals. At physiological pH, boric acid binds to NAD, a coenzyme in metabolism and substrate for an enzyme in the NAD cADPR system of calcium signaling.

Boron, an element ubiquitous in the earth’s crust can be found in most soil types as well as in fresh and salt water, consequently, boron is a natural constituent in the human diet (Nemodruk and Karalova, 1969, Meacham and Hunt, 1998). In a typical adult daily intakes of boron were measured to be approximately 1 mg/day (Meacham and Hunt, 1998, Rainey et al. 1999). Boron is considered an essential micronutrient for higher plants; however, the most recent US dietary recommendations concluded that insufficient evidence existed to consider boron an essential micronutrient for humans (Warrington, 1923, Loomis and Durst, 1992, IOM, 2001). However, evidence does exist that indicates boron plays a beneficial role in some physiological processes of various animal species and measurable responses to adjusted boron intakes in humans have been observed (Rowe and Echkert, 1999, Nielsen, 1998).

This report summarizes the recent research efforts to estimate the dietary intakes of both boron and silicon in the Chinese adult male population. In addition, the primary sources of boron in the Chinese diet were identified and compared to the previously identified primary dietary sources of boron in diets from the United States, Germany, Great Britain, Mexico, Kenya, and Egypt.