STUDIES ON CALCIUM NUTRITION OF TOMATO PLANTS

Transcription

1 STUDIES ON CALCIUM NUTRITION OF TOMATO PLANTS By SUAD AMGADA ABDEL-KADER B.Sc. Agric. Sci. (Soil Sciences), Fac. Agric., Omar Al Mokhtar Univ., Libya, M.Sc. Agric. Sci. (Soil Sciences), Fac. Agric., Omar Al Mokhtar Univ., Libya, THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY In Agricultural Sciences (Soil Sciences) Department of Soil Sciences Faculty of Agriculture Cairo University EGYPT 2012

2 INTRODUCTION Tomato is one of the most important vegetable crops cultivated worldwide (Peet, 1992), not only because of its economical importance, but also due to its high nutritional value. With the increasing demand by consumers and the introduction of quality labels, fruit quality has become a commercial concern (Guichard et al., 2001). Fruit quality and marketable yield of tomato are substantially impaired by the physiological disorder blossom-end rot (BER) representing major cause for non-marketability in tomato. Yield losses caused by BER can amount up to 50% (Taylor and Locascio, 2004). It is widely accepted that BER is mainly caused by a combination or sequence of environmental and physiological factors related to calcium (Ca) uptake and transport within the plant and to fruit growth rate and/or fruit size (Ho and White, 2005). The majority of studies identified a local calcium deficiency in the distal fruit tissue during the period of rapid cell expansion, when Ca demand exceeds Ca supply, as the primary cause of BER (Bradfield and Guttridge, 1984; Adams and Ho, 1993 and Ho and White, 2005). Additional Ca application was frequently considered as a preventive mean to overcome local Ca deficiency in tomato (Schmitz et al., 2002). The similarities in transport mechanisms of Ca and B within the plant and their role in stabilizing cell wall structures suggest a positive impact of an additional application of these elements regarding BER.

3 Therefore, the objectives of the present study are 1. Classification of some tomato varieties according to their Ca-use efficiency. 2. Classification of some tomato varieties according to their susceptibility to blossom-end rot. 3. Evaluating effectiveness of foliar application of Ca, CaB and CaZn to tomato fruits as means to reduce BER-affected fruits. 2

4 REVIEW OF LITERATURE Calcium plays a major role in cell wall stability and in regulating plant senescence and fruit ripening (Gerasopoulos and Drogoudi, 2005 and Thorsten et al., 2009). Kevin et al., (2000) mentioned that, calcium is a divalent cation that is extremely important in maintaining the strength of stems and stalks of plants, this nutrient also regulates the absorption of nutrients across plasma cell membranes, plant cell elongation and division, structure and permeability of cell membrane, nitrogen metabolism and carbohydrate translocation. Calcium's physiological activity as a second messenger in cellular biochemistry and its requirement in cell wall structure make it important to fruit growth and development as well as general fruit quality, disease resistance (Kadir, 2004; Kazuhiro et al., 2004; Elmret et al., 2006 and Lanaouskas and Kvikliene, 2006). 1. Calcium deficiency symptoms in horticultural crops Calcium availability is a major problem for vegetable crops, reduced it's availability in soil can lead to deficiency and as a result losses and reduced crop quality. In numerous horticultural crops calcium deficiency can cause physiological disorders e.g. blossom-end rot (BER) in tomato and pepper varieties or bitter pit in apple fruits, tip burn of lettuce and black heart of celery (Harker and Ferguson, 1991 and Masariambi et al., 2009). This problem is particularly important in tomatoes, where calcium deficiency often lead to blossom-end rot during periods of reduced plant transpiration (Prasad et al., 2009). 3

5 Salisbury and Ross (1992) found that, deficiency symptoms are most in young tissues meristematic zones of roots, stems and leaves where cell division is occurring. If a calcium deficiency is present, it well result in twisted and deformed tissues and the meristematic zones die early as in the case of blossom-end rot of tomatoes, water melons, internal brown spot in potatoes and soften non-marketable fruits in general. Ho and White (2005) and Saure (2005) concluded that, the main cause for calcium deficiency in fruit is its low mobility in the plant from matured tissues to young ones. Bar-Tal et al. (2001 a,b) and Ho and White (2005) showed that, calcium deficiency in the fruit may be caused by inadequate calcium uptake, caused, inturn, by low calcium concentration in the solution and by antagonism with other cations (K +, NH + 4 ). Marschner (1995) and Jeschke and Pate (1991) found that, calcium is a divalent ion and as the valence of ion increases the uptake decrease. Calcium uptake is limited to the very young section of the roots and the nutrient is transported toward the xylem mainly by apoplectic flux, with little translocation in the phloem. Matthew and Salvadore (2004) reported that, blossom-end rot is related to many factors including: high salinity, high magnesium, ammonium and/or potassium concentration, inadequate xylem tissue development, accelerated growth rate, unfavorable moisture relationships (high, low or fluctuating), low soluble soil calcium, high temperature and high and low transpiration, but the underlying cause of this disorder is an inadequate amount of calcium in the blossom-end rot of the fruit. They added that, although it is widely accepted that a local calcium deficiency plays an important role in the induction of BER, 4

6 there are also some claims that calcium deficiency is not the cause of BER as a critical level of calcium concentration for BER induction has not been found. 2. Occurrence of blossom-end rot in tomato plants Blossom-end rot is a very common physiological disorder. Mostly for tomato, pepper and eggplant, so far most studies have been done on BER and it has been reported to have come as a result of low calcium levels in fruit distal due to competition for calcium uptake with other mineral nutrients in the soil (Gunes et al., 2002). Ho et al., (1993) and Grattan and Grieve (1999) reported that, calcium nutrition of tomato demands special attention because this nutrient is intimately involved in the occurrence of the physiological disorder BER, which may considerably reduce fruit quality and market acceptability. Adams (2002) found that, BER is caused by a local deficiency of calcium in the distal part of the fruit, which results in a disruption of tissue structure in that area. Gunes et al., (2002) stated that, uptake of calcium occurs in the first few weeks of fruit growth when cell wall develop, at mature stage of fruit development, calcium is transformed into water soluble form and move from the cell wall. Wui and Takano (1995) and Bar- Tal and Benny (2005) showed that, calcium uptake and transport in plant is strongly dependent on transpiration and air flowing over fruit clusters reduced BER incidence. Bradfield and Guttridge (1984) found that, the calcium concentration in the wall tissue of the distal segment of fruits damaged by BER was 0.03% of dry matter. 5

7 Adams and El-Gizawy (1986) showed that, healthy fruit contained more than 0.07% calcium whereas those with blossom-end rot contained less than 0.05% Ca 2+. Saure (2001) mentioned that, the critical concentration of calcium in tomato fruits has not yet been found. He added that there is no conclusive evidence for a role of calcium when BER is induced by various environmental stresses. Nonami et al,. (1995) found that, no universal critical calcium level in the blossom-end rot fruit tissue has been identified. Nukaya et al., (1995) found that, BER can be induced by changing the concentrations of mineral nutrients other than calcium in the feed. Many attempts to define critical values or even to correlate BER incidence with calcium concentration or the K + / Ca 2+ ratio in tomato and pepper fruits have failed (Chiu and Bould, 1976; Nonami et al., 1995; Saure, 2001 and Bar- Tal et al., 2006). Possible reasons are: i- the fruit is susceptible to the calcium concentration and the K + /Ca 2+ ratio only during a very short period in early fruit development. ii- the calcium concentration in the fruit is very low and varies with the distance between the distal part and the blossom-end rot, the critical calcium concentration for the induction of BER may vary with environmental conditions that affect the fruit growth rate (Ehret and Ho, 1986; Ho et al., 1993; Marcelis and Ho, 1999 and Ho and White, 2005). BER occurs during a period of cellular calcium demand, when fruit growth is accelerated or calcium delivery to the fruit is limited, it is initiated by a cellular dysfunction in a fruit cell during expansion in 6

8 response to a local transient Ca-deficiency (Bar-Tal et al., 2001a; Ho and white, 2005; Bar- Tal et al., 2006 and Turhan et al., 2006). Bar-Tal et al., (2001a) reported that, better correlation of BER incidence with calcium concentration was obtained when analyses of fruit sections were used. However, Nonami et al., (1995) failed to establish a correlation between BER incidence and calcium concentration in tomato fruit that were divided into several sections. Saure (2001) concluded that, stress rather than calcium supply was the main causative factor of BER. 3. Calcium distribution in BER- affected tomato fruit Mineral nutrients such as potassium are transported readily in the phloem; localized deficiencies of these nutrients are prevented by redistribution within the shoot. By contrast, calcium appears to be virtually immobile in the phloem; it is transported through the plant almost entirely via the xylem (Raven, 1977 and Adams and Ho, 1993). Adams and Ho (1993) found that, xylem flow carry the transpiration stream and is normally entirely acropetal. Thus, once deposited in a transpiring tissue, calcium will be trapped there and unable to exit to other parts of the shoot. Because of these factors, low transpiring fruit tissues will have relatively low calcium levels and will be prone to deficiency disorders such as blossom-end rot, a necrosis of the distal region of the fruit in tomato and pepper. Calcium uptake and transport in the plant is strongly dependent on transpiration, therefore, the calcium concentration in transpiring organs such as leaves is higher than that in non-transpiring organs such as flowers and fruits (Clarkson, 1984 and Hanson, 1984). 7

9 Marschner (1995) mentioned that, a high proportion of the total calcium in the plant tissue is often located in the cell walls; this unique distribution is mainly the result of an abundance of binding sites for calcium in the cell walls. Nonami et al., (1995) found that, the concentration of calcium ion was significantly lower in fruits than in stems, leaves and roots. However, fruits that just started having BER had similar distribution and concentration of ions compared with the normal fruits. Also they concluded that, calcium deficiency in fruits may not be the direct cause of the occurrence of BER in tomato plants. Bradfield and Guttridge (1984) reported that, adding extra calcium to the nutrient solution increased the calcium concentration in the proximal, but not in the middle or distal segments of the fruit. Suzuki et al. (2003) concluded that, some calcium precipitates were localized in the cytosol, nucleus, plastid and vacuoles at an early developmental stage of normal fruits, calcium precipitates were increased markedly on the plasma membrane during the rapid fruit growth stage compared with their level at the early stage cell, collapse occurred in water-soaked region at the rapid fruit growth stage in BER fruits. They added that, the amount of calcium precipitates on plasma membranes near collapsed cells was smaller than that in the cell of normal fruits and normal parts of BER fruits and the amount on cells near collapsed cell was small. They concluded also that, the distribution pattern of the calcium precipitates on the plasma membrane was thus considerably different between normal and BER fruits. Hence, calcium deficiency in plasma membranes caused cell collapses in BER tomato fruit. 8

10 Saure (2001) reported that, the symptoms of BER are caused by a disintegration of the cell membranes and an increased of permeability causing the deterioration of cell membranes and on increased of permeability causing the deterioration of cell membranes with subsequent loss of turgor and leakage of cell liquids. Kim et al., (2008) showed that, calcium contents of tomato fruits varied by cluster numbers standing for their development stage and those in the first and third clusters were greater than that in the fifth cluster. Results indicated that, calcium delivery to the fruits can be manipulated by controlling nutrient solution composition in a certain period of time during tomato cultivation. They added that, the protocol of management of nutrient solution can be applied for Ca- rich fruit production that reduces blossom-end rot and increases storagbility of tomato fruits. 4. Factors affecting the incidence of BER Ho and White (2005) found that, all environmental and generic factors that influence the occurrence of BER in tomato affect either the rate of cell expansion or the delivery of calcium to young fruit. It has been observed that BER occurs solely in distal fruit tissue during the initial phase of rapid cell expansion and vaculation before any locular tissue is present, thus, BER occurs during a period of high cellular calcium demand, when fruit growth is accelerated or calcium delivery to the fruit is limited. 9

11 a. Environmental factors The induction of BER in young fruit is influenced by numbers of environmental factors, these are most likely to exert their effects by affecting the transport of calcium to the fruit and/or the rate of cell expansion such as: 1. Salinity The inhibiting effect of salinity on fruit growth was observed by Aktas et al., (2005) and Bar-Tal et al., (2003) who reported that, irrigation with saline solution caused a substantial increase in the percentage of BER affected fruits especially when the temperature increased during the spring and summer. Adams and Ho (1992) showed that, the increase in the occurrence of BER affected fruits under irrigation with saline water has been related to reduced calcium uptake and transport into the fruits. However, Aktas et al., (2005) found that, irrigation with saline water that contained high calcium concentration had no effect on the concentration of calcium in BER- free fruits at their initial developmental stage. Whereas, the calcium concentration in the leaves was slightly increased. They also found that, high salinity caused a substantial decrease in the concentration of manganese in both of the fruits and the young leaves. Chretien et al., (2000) stated that, increasing salinity by NaCl resulted in neither an increase of BER incidence nor a decrease of fruit calcium concentration of Rockwool grown tomatoes. 10

12 Adams and Holder (1992) found that, there is no linear relationship between salinity and BER and the responses of susceptible cultivars to some environmental stress differ. Adams and Ho (1993) concluded that, the very high incidence of BER induced when the salinity was increased with major nutrients may be due to both a low calcium level and a high concentration of free acids in the affected tissues. Ehret and Ho (1986) reported that, a high concentration of organic acids may reduce the availability of calcium in the tissues and so render the fruit more susceptible to BER. Belda and Ho (1993) found that, both the uptake and transport of calcium within the plant as well as xylem development inside the fruit are restricted by high salinity. Hence, salinity has a profound effect on the induction of BER. 2. Climate a. Humidity Banuelos et al., (1985) and Tadesse et al. (2001) reported that, increasing the humidity of the air close to the fruit enhanced the incidence of BER in pepper fruit. The effects of air temperature and humidity on BER incidence have been related to their impact on the supply of calcium to the fruit (Wiersum, 1966; Ho, 1989; Brown and Ho, 1993; Ho et al., 1993 and Ho and White, 2005). Bradfield and Guttridge (1984) reported that, the positive root pressure at night promotes transport of calcium into tissues and organs that have restricted transpiration. 11

13 Adams and Ho (1993) showed that, high humidity reduced calcium import by the leaves, but increased that by the fruit and they found that, the cause of BER is usually an interaction between the effects of irradiant and ambient temperature on fruit growth and the effects of environment at stress on calcium uptake and distribution within the whole plant. Wui and Takano (1995) and Gunes et al., (2002) concluded that, the BER incidence due to higher the temperatures was correlated with a rapid fruit growth rate during the early stage of fruit development at high temperatures. Francisco et al., (2006) reported that, calcium supply and consequently calcium concentration in the tomato plant can be reduced drastically for short-term periods during the vegetative growth stage without any adverse effect on growth, whilst higher humidity reduce both growth and calcium concentration in young vegetative tomato plants. Consequently, reduced calcium uptake at high air humidity is not the cause for the reduction in growth. Soria et al., (2002) found that, additional stress factors prevailing such as low temperature during winter or very low ambient humidity during spring-summer could have affected calcium uptake and/or calcium distribution within the plant. Therefore, calcium translocation and distribution in plant are controlled by environmental conditions that affect the transpiration and water status of plant organs (Brown and Ho, 1993, Ho, 1989 and Ho et al., 1993). Adams and Holder (1992) and Ho et al., (1993) reported that, under environmental conditions which enhance transpiration i.e, low humidity and high temperature, the calcium concentration in the leaves increased whereas that in the fruit decreased. 12

14 Elder et al., (1998) showed that, fruit kept at low humidity had higher calcium accumulation although the excessive water loss from tissues may lead to BER when calcium doses are supplied to plants. Carson (2009) found that, fluctuations in soil moisture lead to the root system will be unable to absorb enough calcium for the needs of growth and fruit development. Wui and Takano (1995) reported that, the incidence of BER increased with increasing temperature from 24 to 28 degrees and with air flow over the top of canopy or expanding leaves, however, air flowing over fruit clusters reduced BER incidence. Taylor et al., (2004) and Adams (2002) found that, higher transpiration and temperature levels enhance water uptake, thereby increasing the transport of calcium to the leaves via the xylem. However, under such conditions, the transport of water to fruits is reduced due to competition with the leaves and thus translocation of calcium to fruits is also restricted there by increasing the percentage of fruits with BER. 13

15 b. An evaporative cooling system (ECS) Bar-Tal et al. (2006) found that, the effect of the evaporative cooling system and shading was probably due to reductions in fruit temperature and transpiration, which improved the ability of the plant to maintain the water supply to the fruit through the xylem. However, no consistent effect of the ECS and shading on the calcium concentration in fruit was found. Bar-Tal et al., (2006) and Turhan et al., (2006) found that, the use of ECS reduced the incidence of BER- affected pepper fruits. Bar-Tal et al., (2006) reported that the air temperature and the incidence of BER increased with the distance from the wet pad and high positive correlations were found between the incidence of BER and the average air temperature at midday during the spring. Walter et al., (2009) concluded that, BER- affected fruits were reduced in a fan and cooling system. Bar-Tal et al., (2006) found that no clear and consistent effect of the ECS on the calcium concentration in the fruit. Thus, the incidence of BER-affected fruits did not correlate with the calcium concentration in the fruits. 3. Soil water stress Adams and Ho (1992 and 1993) showed that, water stress was the most common cause of BER. They also noticed that, BER frequently occurred when the moisture content of the substrate was fully adequate. Bar-Tal et al. (2001c) reported that, the lowest BER incidence was obtained when the most frequent irrigation was combined with the highest solution calcium concentration. 14

16 Bar-Tal and Benny (2005) found that, increasing the irrigation frequency in soilless culture from 1 to 12 times a day reduced the percentage of BER-affected pepper fruits from 35 to 25%. Turhan et al., (2006) reported that, high irrigation frequency enhanced the calcium concentration in the leaves and fruits, especially in the low-ca treatment and minimized the amplitude of the fluctuations in the water content of the growth medium and these effects of the high irrigation frequency probably enhanced the calcium uptake and reduced the BER. Silber et al., (2005) reported that, increasing the fertigation frequency from 2 to 8 applications per day reduced the number of BER-affected fruits from 7 to 3 per plant, respectively and increased the yield of export-quality fruits from 6.5 to 10 per plant, respectively. Kalra (2006) found that, BER can be caused when, calcium and/or water levels in the root zone are low. Generally, calcium is plentiful and low water levels are the cause of the calcium deficiency in the fruit where the plant takes up insufficient amount of calcium to meet the plant demand. Carson (2009) mentioned that, the cause of BER is not enough calcium in the plant to meet its growth and fruit development needs that can be caused by larger fluctuations in soil moisture. b. Nutrients composition effects 1. NH + 4 /NO - 3 ratio The nitrogen form is an important factor for plant development and yield. Ganmore and Kafkafi (1980) found that, increasing the NH 4 -N : NO 3 -N ratio in the nitrogen fertilizer reduced the uptake of other 15

17 mineral cations, but increased the uptake of mineral anions by tomato plant. Bar-Tal et al., (2001b) reported that, the uptake of Ca +2 and K + increased quadratically as the NO 3 -N: NH 4 -N ratio increased. Albahou (1999) showed that, application of NH4 + - fertilizer or higher NH /NO 3 ratio in the nutrient solution are often associated with increased incidence and severity of BER. Wilcox et al., (1973) indicated that, NH + 4 -N application during fruiting of tomato plants in sand cultures may cause symptoms of BER within 7 days. Bar-Tal et al., (2001a) found that, the occurrence of BER in pepper fruits could be reduced by fertigation in which the nitrogen supply contained a low ammonium fraction. They showed that, BER incidence was well correlated with the calcium content in young fruits. Ho et al., (1993) reported that, high radiation intensity, combined with NH + 4 nutrition, increased the incidence of BER in tomato plants. Hartman et al., (1986) observed that, incidence of BER was increased and fruit size was severely reduced by increasing NH /NO 3 ratio in the nutrient solution, but the percentage of calcium in the fruit was unaffected by increment of NH + 4. Pill et al., (1978) and Barker and Ready (1994) found that, lower content of calcium in the fruit of NH + 4 grown plants as compared to NO - 3 ones, but no differences in the percentage of calcium at different NH + 4 levels and no difference in the calcium concentration between fruits with and without BER, respectively. 16

18 Paraikovic et al., (2010) showed that, calcium concentration in leaves and stems was under influence of high air temperature and N form which strongly correlated with BER appearance. They added that, the NH + 4 -N treatment gave the lowest yield, due to high incident of BER tomato fruit. 2. K + /Ca 2+ ratio Taylor et al., (2004) found that, the use of a high K + /Ca 2+ ratio in fertilizing tomato plants has been reported to increase the proportion of tomato fruits showing BER. Wui and Takano (1995) showed that, fruit Ca content decreased whereas K content increased with increasing BER incidence. Bar-Tal and Pressman (1996) found that, the occurrence of BER increased steeply, from 6.8 to 25.5% when they increased the potassium concentration in a hydroponic system from 2.5 to 10.0 mmol/l at constant calcium concentration; whereas elevating the calcium concentration from 3.0 to 7.0 mmol/l reduced the occurrence of BER from 13.7 to 3.3%. Increasing the K concentration from 2.5 to 10 mmol/l increased the K concentration in plant organs and the K uptake rate, but reduced that of Ca. However, they found very poor correlations among the incidence of BER, the concentrations of Ca and K and the K/Ca ratio, in ripe fruits, but they found high correlation between the incidence of BER and the K/Ca ratio in the leaves. 3. Effects of Ca 2+ and Mg 2+ concentrations of soil solution Calcium and magnesium are both alkaline earth elements that are taken up by plants as divalent cations. Hao and Papadopoulos (2004) reported that, there was an increase in the incidence of BER- affected tomato fruits as the Mg 17

19 concentration increased from 20 to 80 mg/l when Ca concentration was 150mg/L; when the Ca concentration was elevated to 300mg/L changing magnesium concentration had no effect. Gunes et al., (2002) showed that, Mg is the first element affect of Ca uptake, the amount of Ca and Mg is quite less in fruit although Mg/Ca ratio is high due to high mobility of Mg transmission of Ca to the fruit is inhibited by high concentration of Mg. C. Genetic factors Blossom-end rot may occur in all the tomato producing areas of the world and has been shown to create losses up to 50% (Matthew and Salvadore, 2004). Kirkby and Pilbeam (1984) and Luttge (1983) mentioned that, the physiological disorders associated with calcium nutrition deficiency are primarily caused by poor calcium distribution within the plant rather than to the restriction in calcium uptake by roots well supplied with calcium. It is considered to be a very immobile element once deposited in plant tissue because of this marked immobility of calcium within plants, crop varieties with known genotypic difference in the efficiency of Ca utilization relatively especially in inactive old leaves. Marschner (1983) reported that, phenotypic differences in Caefficiency have been reported to be associated with genotypic differences in Ca uptake, transport and distribution. Greenleaf and Adams (1969) showed that, in tomatoes, several breeding lines differing widely in the resistance to the blossom end rot associated with Ca utilization were developed. Leonardo et al., (1982) showed that, inheritance studies indicated that additive gene effects made major contributions to 18

20 variations in response to low Ca. They added that, at least 2 factors are involved in the observed differences in Ca efficiency. First, some efficient lines are more able to remove Ca from the low-ca solution and a difference in Ca utilization followed absorption is a second factor in efficiency. Ho et al., (1995) concluded that, neither Ca-efficiency nor a high calcium uptake are a sound basis for the selection of tomato cultivars for resistance to BER, the crucial factor is the ability to divert sufficient calcium away from the leaves to the trusses and particularly to the distal part of the fruit. Glordano et al., (1982) showed that, there is a wide range of plant growth responses to Ca-stress in tomato cultivars. Li and Gabelman (1990) reported that, apparently the high plant dry weight of Ca-efficient types may account for a high portion of the genetic characteristics in Ca-efficiency. English and Mayard (1981) found that, the differences in Ca-efficiency among strains under Ca stress may remain with an adequate supply of Ca in the feed. Greenleaf and Adams (1969) showed that, as Ca-efficiency appeared to be linked to BER-resistance it has been suggested that Caefficient types may be a useful source when selecting for BERresistance. Previous workers have used the Ca-efficiency ratio, i.e. dry matter production in relation to calcium absorbed (Glordano et al., 1982), and the concentration of calcium in different plant parts (Behling et al., 1989), to assess the efficiency of plant growth when the Ca supply was limited. 19