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International Journal of ChemTech Research CODEN (USA): IJCRGG, ISSN: 0974-4290, ISSN(Online):2455-9555 Vol.9, No.12 pp 230-245, 2016
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Foliar spray with potassium nitrate and salicylic acid for improving growth, yield and nutrients uptake by olive trees under salinity stress conditions
I. E. Abd-El-Rhman1 and M. F. Attia2
1 Plant Production Department and 2Soil Fertility and Microbiology Department, Desert Research Center, Cairo, Egypt.
Abstract : A field experiment was conducted at Ras – Sudr, South Sinai Governorate, Egypt located at 29º 32'28" N and 32º 39'25 '' E during two successive seasons, 2015 and 2016 on 96 Manzanillo olive tree, of about 8 years old grown on sandy loam soil to study the effect of foliar spray with potassium nitrate (KN) and salicylic acid (SA) on improving growth, yield and nutrients uptake by olive trees under salinity stress conditions . The soil was irrigated with water of 7.85dSm-1 and with soil paste extract of 8.56dSm-1. The experiment was carried out using spilt plot randomized complete blocks design with the main plots being salicylic acid (SA) at 0, 250, 500 and 1000 mg SA L-1, and sub –plots potassium nitrate (KN) at 0, 10, 20 and 30 g KN L-1 with three replicates and two trees per each replicate. The trees were sprayed 3 times; at vegetative stage, beginning of flowering and after fruit setting. All growth, yield and fruits physical and chemical properties, , total chlorophyll and proline contents in leaf and leaf nutrients uptake increased by increasing application of SA and KN either separately or in combinations. The most effective treatments were 1000 mg SAL-1 and 30gKNL-1. Combination of the two treatments was the most effective.
Keywords: Foliar spray, potassium nitrate, salicylic acid, olive trees, salinity stress conditions.
Introduction
Olive (Olea europaea L.) is a long-lived evergreen tree, one of the most widely cultivated and economically important fruit crop for several countries, olive native to the Mediterranean basin that accounts for about 90% of the world's olive cultivation and production. In Egypt the total harvested area is 64835 ha with a production of 1320800 Mg (megagrams) 1.The use of saline water for irrigation requires an adequate understanding of how salts affected soil characteristics and plant performance 2. The relationship between saline water and olive cultivation has been intensively studied 3,4. Saline conditions limit the vegetative and reproductive development of olives mainly as a result of interference with the osmotic balance in the root system zone and detrimental effects caused by specific toxic accumulation of chloride and sodium ions in the leaves 5. Salinity is one of the main factors limiting crop productivity 6. Salinity stress is always accompanied by changes in plant metabolism, which in turn affects plant constituents. The most harmful effect is the reduction of water availability to plants. Salinity accumulates Cl- and Na+ ions in toxic contents in plant and minimizes foliar pigments 7. High irrigation water salinity of up 8000 mg soluble salts L-1 was reported to increase leaf osmotic potential and decrease leaf contents of 8.
Salicylic acid (SA) could induce the alternative oxidase enzyme activity in mitochondria which is involved in stress alleviation and enhances specific secondary metabolites of plants 9. Spraying SA at 300 mgL-1 increased orange growth, fruit setting and yield 10. SA is most readily accessible as plant growth regulator compared with acetyl salicylic acid and methyl salicylate 11 ,, and it is safe to human and environment
and plays an important role in protecting plant cells from senescence. It minimizes the effects of stresses conditions and enhances natural hormones regulate plant growth and development 12. It enhances yield and fruit quality of different fruit crops 13, 14,15 and acts as hormone-like substance, which plays important roles in regulating and resisting abiotic stresses 16,17. Spraying SA on pistachio nut trees increased nut fresh weight and decreased blank nut percentage 18.
Potassium is an essential plant nutrient and under salinity stress, metabolic toxicity of Na is largely due to its ability to compete with K for binding site essential for cellular function 19. Foliar K application of as potassium nitrate at 40g potassium nitrate L-1 after final fruit setting or pit hardening improved the vegetative growth 20. Potassium alleviates the adverse effects of salinity on plant growth by regulating the desirable K/Na ratio 21. Its foliar application improved nutrient status and increased salt tolerance 22 and plays an important role in the synthesis of amino acids and proteins as well as translocation of sugars and assimilates within the plant and accumulating carbohydrates 23. It controls cell water content and carbohydrate biosynthesis in plant tissues 24, 25,26, and in N uptake and translocation from roots to vegetative growth 27. Toleration of salinity by plant depends on its status in leaves 28. Potassium by date palm seedling increased with the increase in salinity 29. Application 4.5kg potassium nitrate per tree of date palm in March, June and September caused highest fruit quality and leaf mineral 30. Potassium nitrate alleviated salinity stress of Valencia orange 31. When potassium was applied in combination with biofertilizers to date palm it increased fruit yield , enhanced leaf chlorophyll content, fruit setting percentage, , fruit quality and leaf minerals content of "Hayany" date palm 32.
Potassium activates the enzymes involved in sugar biosynthesis and helps in translocation of sugars and affects the quantity and quality of dates 33. It has a positive role in plant growth under saline conditions 34, and is required for physiological processes such as activation of enzymes, regulation of osmotic pressure and stomata movement 35. It reduces excess uptake of ions such as sodium and iron under saline conditions and plays an important role in alleviating stress conditions 36 ,37.
The aim of the present investigation was to study the effect of foliar spray with potassium nitrate and salicylic acid on growth, yield and nutrient uptake by olive trees under salinity stress conditions.
Material and Methods
This study was conducted at Ras – Sudr, South Sinai Governorate, Egypt for two successive seasons, 2015 and 2016 on a number of 96 trees of10-year old Manzanillo olive , grown on a loamy sand soil. The trees were healthy, uniform in growth, vigor and fruiting and received regularly the same cultural practices. Soil and irrigation water analyzed according to Chapman and Pratt 38 and the data are presented in Table 1.
Table 1 : Physical and chemical analysis of the soil and irrigation water ofn the experiment
Soil depth (cm) |
Soil particles distribution (%) |
Texture |
CaCO3 gkg-1 |
EC dSm-1 |
pH |
||||
sand |
silt |
clay |
|||||||
0-30 |
81.2 |
8.57 |
10.23 |
Sandy loam |
269.9 |
8.56 |
7.7 |
||
30-60 |
80.08 |
10.59 |
9.33 |
Sandy loam |
224.8 |
7.35 |
7.9 |
||
|
Soluble ions (mmolc L-1) in soil past extract |
||||||||
|
Ca2+ |
Mg2+ |
Na+ |
K+ |
SO4- |
Cl- |
HCO3 |
CO3 |
|
0-30 |
24.5 |
5.2 |
57.2 |
8.8 |
26.2 |
61.5 |
8.0 |
0.0 |
|
30-60 |
16.8 |
3.8 |
42.5 |
12.9 |
23.5 |
49.0 |
3.5 |
0.0 |
|
EC, pH and Soluble cations and anions in water of irrigation (mmolc L-1) |
|||||||||
EC dSm-1 |
pH |
Soluble Cations |
Soluble Anions |
||||||
Ca2+ |
Mg2+ |
Na+ |
K+ |
SO4-2 |
Cl |
HCO3- |
CO3-2 |
||
7.85 |
7.7 |
20.5 |
8.5 |
52.95 |
0.35 |
19.8 |
57.5 |
5 |
nd |
The experiment was carried out using spilt plot randomized complete blocks design with the main plots being salicylic acid (SA) at 0, 250, 500 and 1000 mg SA L-1, and sub –plots potassium nitrate (KN) at 0, 10, 20 and 30 g KN L-1 with three replicates and two trees per each replicate. Trees were labeled and treatments were undertaken. The trees were sprayed three times; at the vegetative growth stage, at beginning of flowering
and after fruit setting. On early March of each season, twenty healthy one-year old shoots well distributed around the canopy of one-year old shoots were randomly selected and labeled (5 shoots of each direction) for carrying out the following measurements: vegetative characteristics such as number of new shoots, shoot length number of leaves per shoot, leaf area 39, and leaf total chlorophyll contents by using Minolta chlorophyll meter SPAD- 502. At full bloom (mid. April) flowering behaviors were recorded i.e. flowering percent , flowering density, sex ratio, inflorescence length and fruit set 40 .At maturity (mid- October), fruits of were harvested and yield was measured. Thirty fruit per each tree were randomly selected for carrying out the fruit quality i.e. fruit dimensions fruit volume , average weight per fruit and fruit moisture content 41 .Fresh oil content 42 ,leaf proline content 43, total soluble solids, leaf mineral content and total acidity of fruit were determined 42.
All the obtained data during both 2015 and 2016 experimental seasons were subjected to analysis of variances (ANOVA) according to 44.
3. Results and Discussion
3.1. Vegetative growth characteristics:
Data in Table 2 indicate that under salt stress conditions application of SA and KN separate or combined gave positive effects. The highest rate of SA caused average increases (for both seasons) of 61.3, 45.3, 55.5 and 22.1% for No. of new shoots, shoot length, No of leaves /shoot and leaf area, respectively. The highest rate of KN gave average increase of 32.5, 18.2, 24.6 and 12.5% for No. of new shoots, shoot length (cm), No of leaves /shoot and leaf area (cm2), respectively.
Combination of 1000 mg KNL-1 with 30g SAL-1 gave an average increase in the number of new shoots, shoot length , No of leaves /shoot and leaf area of ; 101.7, 78.9, 92.5 and 30.3%, respectively for both seasons.
Salicylic Acid (SA) |
KNO3 (KN) “ g L-1 " |
|||||||||
None |
10 |
20 |
30 |
Mean |
None |
10 |
20 |
30 |
Mean |
|
Season 1 |
Season 2 |
|||||||||
No of new shoots |
||||||||||
None |
5.33 |
6.67 |
6.33 |
7.33 |
6.42 |
6.33 |
6.00 |
7.33 |
8.00 |
6.92 |
250 mg L-1 |
6.00 |
7.67 |
8.67 |
9.00 |
7.83 |
8.00 |
9.33 |
9.33 |
10.00 |
9.17 |
500 mg L-1 |
7.33 |
9.33 |
8.67 |
9.67 |
8.75 |
9.33 |
10.67 |
10.67 |
11.33 |
10.50 |
1000 mg L-1 |
8.33 |
10.33 |
11.67 |
11.67 |
10.50 |
9.00 |
11.67 |
11.67 |
11.67 |
11.00 |
Mean |
6.75 |
8.50 |
8.83 |
9.42 |
|
8.17 |
9.42 |
9.75 |
10.25 |
|
LSD0.05 |
SA=0.05, KN=0.05, SA× KN =1.01 |
SA=0.06, KN =0.06, SA× KN =1.02 |
||||||||
|
Shoot length (cm) |
|||||||||
None |
14.7 |
17.5 |
18.0 |
18.1 |
17.1 |
15.1 |
16.7 |
20.0 |
21.0 |
18.2 |
250 mg L-1 |
19.0 |
23.2 |
24.2 |
24.9 |
22.8 |
20.7 |
22.0 |
23.5 |
25.0 |
22.8 |
500 mg L-1 |
25.6 |
24.2 |
24.3 |
24.7 |
24.7 |
21.8 |
25.3 |
25.1 |
26.0 |
24.5 |
1000 mg L-1 |
24.1 |
26.2 |
27.0 |
26.8 |
26.0 |
22.4 |
26.2 |
26.3 |
26.2 |
25.2 |
Mean |
20.8 |
22.8 |
23.4 |
23.6 |
|
20.0 |
22.6 |
23.7 |
24.6 |
|
LSD0.05 |
SA= 0.04, KN =0.04, SA× KN =0.08 |
SA=1.01, KN =1.01, SA× KN =2.02 |
||||||||
|
No of leaves/shoot ratio |
|||||||||
None |
18.3 |
21.7 |
22.7 |
24.3 |
21.8 |
19.3 |
21.0 |
23.7 |
25.0 |
22.3 |
250 mg L-1 |
20.0 |
25.0 |
26.7 |
28.0 |
24.9 |
27.3 |
27.7 |
30.3 |
32.7 |
29.5 |
500 mg L-1 |
24.7 |
27.7 |
29.7 |
31.3 |
28.3 |
33.0 |
35.3 |
36.0 |
37.7 |
35.5 |
1000 mg L-1 |
27.3 |
32.3 |
34.7 |
34.7 |
32.3 |
32.7 |
37.3 |
37.7 |
37.3 |
36.3 |
Mean |
22.6 |
26.7 |
28.4 |
29.6 |
|
28.1 |
30.4 |
31.8 |
33.2 |
|
LSD0.05 |
SA=0.82, KN =0.82, SA× KN =1.63 |
SA=1.42, KN =1.42, SA× KN =2.84 |
||||||||
|
Leaf area (cm2) |
|||||||||
None |
3.23 |
3.28 |
3.29 |
3.25 |
3.26 |
3.27 |
3.44 |
3.52 |
3.64 |
3.47 |
250 mg L-1 |
3.29 |
3.53 |
3.55 |
3.56 |
3.48 |
3.21 |
3.86 |
3.92 |
4.10 |
3.77 |
500 mg L-1 |
3.55 |
3.90 |
3.90 |
3.90 |
3.81 |
3.43 |
4.23 |
4.15 |
4.21 |
4.00 |
1000 mg L-1 |
3.84 |
4.16 |
4.22 |
4.15 |
4.09 |
3.79 |
4.21 |
4.25 |
4.22 |
4.12 |
Mean |
3.48 |
3.72 |
3.74 |
3.72 |
|
3.42 |
3.94 |
3.96 |
4.04 |
|
LSD0.05 |
SA=0.041, KN =0.041, SA× KN =0.083 |
SA=0.097, KN =0.097, SA× KN =0.195 |
Therefore foliar application treatments positive effect can be arranged as follows Salicylic acid + potassium nitrate > Salicylic acid > potassium nitrate, (Fig. 1).
Fig.1: Average increase percentages for vegetative characteristcs of Manzanillo olives in both studied seasons (the highest significant treatment compared with the none treated )
In addition, as shown in Fig.1 it can be concluded that all the studied vegetative growth characteristics can be arranged according their affecting by the foliar sprays of SA, KN and their interaction as follows: No. of new shoots > No of leaves/shoot > shoot length > leaf area.
These results are in agreement with those obtained by 9, 31,10 on Orange trees. Also, these results are in accordance with45 who demonstrated that adding potassium, increased leaf surface, vegetative growth, net photosynthetic rate and chlorophyll content of plants. In this respect, in addition 20 stated that, foliar application of potassium nitrate at 4% after final fruit set or pit hardening improved the vegetative growth. On the other hand, the effect of K on increasing olive trees growth was confirmed by 46,47.
The beneficial effect of SA application on mitigated effect of salinity on all growth tree parameters may be attributed to the important role of Salicylic acid that is involved in minimizing of the stresses through enhancing antioxidant system. It is responsible for enhancing natural hormones that play a key part in regulating plant growth and development 13. In this respect, Salicylic acid is the most readily accessible plant growth regulators which are effective in other forms of acetyl salicylic acid and methyl salicylate in plant as well 12. Salicylic acid (SA) is considered as a hormone-like substance, which plays an important role in the regulation of plant growth and development, seed germination, fruit yield, rooting of cuttings and resistance to abiotic stresses 16,17.
Regarding the effect of K on increasing olive trees growth was confirmed by46,47. This result was in agreement with 45 who demonstrated that adding potassium, increased leaf surface, vegetative growth, net photosynthetic rate and chlorophyll content of plants. Generally the essential element potassium has a great regulatory role within plant cells and organs such as activating more than 50 enzymes, osmosis regulation and photosynthesis and loading and unloading of sugars in phloem48.
The enhancement effect of potassium nitrate application on mitigated effect of salinity on all growth tree parameters may be attributed to the important role of potassium in nutrient and sugar translocation in plant and turgor pressure of plant cells. Also potassium active numerous enzyme systems involved in the formation of organic substances and in the buildup of compounds such as starch or protein. Potassium is involved in cell enlargement and in triggering the young tissues or be due to that potassium is involved in plant mersitematic growth 49,34,35.
3.2. Flowering characteristics:
Results in Table 3 indicate that under salt stress conditions application of SA and KN separate or combined gave positive effects. The highest rate of SA caused average increases (for both seasons) of 25.6, 38.1, 26.1 and 46.6% for flowering%, flowering density, sex ratio, and inflorescence length (cm), respectively. The highest rate of KN gave average increase of 12.0, 13.7, 9.5 and 13.5% for flowering%, flowering density, sex ratio, and inflorescence length (cm), respectively.
Combination of 1000 mg KNL-1 with 30g SAL-1 gave an average increase in the flowering%, flowering density, sex ratio and inflorescence length (cm) of 6.0, 63.8, 33.0, and 54.7%, respectively for both seasons.
Table3: Effect of salicylic acid and potassium nitrate foliar application on flowering characteristics of Manzanillo olives
Salicylic Acid (SA) |
KNO3 (KN) “ g L-1 " |
|||||||||
None |
10 |
20 |
30 |
Mean |
None |
10 |
20 |
30 |
Mean |
|
Season 1 |
Season 1 |
|||||||||
Flowering % |
||||||||||
None |
2.41 |
2.53 |
2.52 |
2.53 |
2.50 |
2.40 |
2.50 |
2.53 |
2.57 |
2.50 |
250mg/l |
2.59 |
2.75 |
2.79 |
2.89 |
2.75 |
2.50 |
2.66 |
2.69 |
2.79 |
2.66 |
500mg/l |
2.65 |
2.95 |
3.06 |
3.15 |
2.95 |
2.65 |
3.00 |
2.97 |
3.02 |
2.91 |
1000mg/l |
2.83 |
3.23 |
3.25 |
3.30 |
3.15 |
2.87 |
3.19 |
3.22 |
3.24 |
3.13 |
Mean |
2.62 |
2.86 |
2.91 |
2.97 |
|
2.61 |
2.85 |
2.85 |
2.89 |
|
LSD0.05 |
SA=0.05, KN =0.05, SA× KN =0.09 |
SA=0.09, KN =0.09, SA× KN =0.18 |
||||||||
|
Flowering density |
|||||||||
None |
44.6 |
47.0 |
46.9 |
48.2 |
46.7 |
44.1 |
57.2 |
61.1 |
61.8 |
56.1 |
250mg/l |
50.4 |
53.7 |
55.1 |
57.8 |
54.3 |
58.1 |
65.6 |
67.0 |
68.0 |
64.7 |
500mg/l |
61.3 |
63.0 |
64.1 |
67.2 |
63.9 |
63.6 |
71.3 |
71.2 |
71.4 |
69.4 |
1000mg/l |
66.1 |
68.9 |
69.3 |
72.1 |
69.1 |
68.7 |
72.4 |
73.1 |
73.2 |
71.9 |
Mean |
55.6 |
58.2 |
58.9 |
61.3 |
|
58.6 |
66.6 |
68.1 |
68.6 |
|
LSD0.05 |
SA= 1.20, KN =1.20, SA× KN =2.39 |
SA=1.74, KN =1.74, SA× KN =3.48 |
||||||||
|
Sex ratio |
|||||||||
None |
55.7 |
57.2 |
56.7 |
57.9 |
56.9 |
55.3 |
55.8 |
58.9 |
59.6 |
57.4 |
250mg/l |
58.1 |
62.1 |
62.9 |
64.2 |
61.8 |
58.5 |
63.8 |
67.6 |
68.1 |
64.5 |
500mg/l |
66.5 |
69.5 |
69.8 |
68.9 |
68.7 |
63.8 |
71.6 |
71.8 |
74.0 |
70.3 |
1000mg/l |
70.3 |
71.5 |
71.8 |
72.5 |
71.5 |
66.0 |
74.5 |
74.6 |
75.1 |
72.6 |
Mean |
62.6 |
65.1 |
65.3 |
65.9 |
|
60.9 |
66.4 |
68.2 |
69.2 |
|
LSD0.05 |
SA=0.91, KN =0.91, SA× KN =1.82 |
SA=1.45, KN =1.45, SA× KN =2.90 |
||||||||
|
Length of inflorescence. |
|||||||||
None |
1.94 |
2.05 |
2.01 |
2.02 |
2.00 |
1.85 |
1.88 |
1.91 |
1.91 |
1.89 |
250mg/l |
2.10 |
2.34 |
2.37 |
2.38 |
2.30 |
1.80 |
1.98 |
2.11 |
2.14 |
2.01 |
500mg/l |
2.48 |
2.64 |
2.71 |
2.67 |
2.63 |
2.00 |
2.55 |
2.67 |
2.79 |
2.51 |
1000mg/l |
2.85 |
2.90 |
2.91 |
2.94 |
2.90 |
2.46 |
2.87 |
2.92 |
2.92 |
2.80 |
Mean |
2.34 |
2.48 |
2.50 |
2.50 |
|
2.03 |
2.32 |
2.40 |
2.44 |
|
LSD0.05 |
SA=0.049, KN =0.049, SA× KN =0.097 |
SA=0.126, KN =0.126, SA× KN =0.252 |
From the aforementioned results it can be concluded that the different foliar application treatments significantly improved the studied flowering characteristics of Manzinello olive trees that are cultivated under salinity stress conditions in the following arrange, interaction of Salicylic acid + potassium nitrate > Salicylic acid > potassium nitrate, (Fig. 2).
In addition, as illustrated in Fig. 2, it can be concluded that all the studied flowering characteristics can be arranged according their affecting by the foliar sprays of SA, KN and their interaction as follows: flowering density > inflorescence length (cm) > flowering% > sex ratio.
Flowering is the main processes influencing the productivity of fruit trees and is particularly important for olive, where biannual bearing is acutely experienced and where there is an apparently delicate relationship between vegetative and reproductive stages of growth50.
SA applied in the appropriate time lead to an increase in length of flowering period. While, the enhancement effect of SA had increased effects flowering parameters, this could be attributed to the role of these materials as thermo genesis in plant 51. Improving flowering percentage and density could be also interpreted to salicylic acid as endogenous growth regulator which plays an important role in increasing antioxidants 52. This interpretation confirmed by 53 who noticed that salicylic acid treatment decreased catalase and peroxidase with concomitant increase in glutathione reductase which play a role in antioxidant action. The mechanism of salicylic acid was reported by 54,55 who concluded that salicylic acid induced flowering by acting as a chelating agent. This view was supported by11 who confirmed that salicylic acid functioned as endogenous growth regulators of flowering effects.
Fig.2: Average increase percentages for flowering and setting characteristcs of Manzanillo olives in both studied seasons (the highest significant treatment compared with the none treated)
The enhancement effect of potassium nitrate may be attributed to the role of potassium e in photosynthesis and osmotic regulation 34 , and to its essentiality for physiological processes such as activation of enzymes, regulation of osmotic pressure and stomata movement35. It reduces excess uptake of ions such as sodium under saline stress. Combining salicylic acid and potassium nitrate had increasing effects on length of flowering period, weight of primary and secondary fruit, and secondary fruits of date palm trees 56.
3.2. Yield parameters:
As shown in Table4 it can be noticed that under salt stress conditions application of SA and KN separate or combined gave positive effects. The highest rate of SA caused average increases (for both seasons) of 24.6, 26.8 and 22.5% for fruit set%, fruit weight (g) and fruit yield (kg/tree), respectively. The highest rate of KN gave average increase of 15.1, 9.4 and 11.9% for fruit set%, fruit weight (g) and fruit yield (kg/tree), respectively.
Combination of 1000 mg KNL-1 with 30g SAL-1 gave an average increase in fruit set%, fruit weight (g) and fruit yield (kg/tree) of 41.1, 34.0 and 37.6% respectively, for both seasons.
Data tabulated in Table4 indicated that the different foliar application treatments significantly improved the studied yield parameters i.e. fruit set%, fruit weight (g) and fruit yield (kg/tree) of Manzinello olive trees that are cultivated under salinity stress conditions in the following arrange, interaction of Salicylic acid + potassium nitrate > Salicylic acid > potassium nitrate, (Fig. 3).
Table 4: Effect of salicylic acid and potassium nitrate foliar application on some yield parameters of Manzanillo olives.
Salicylic Acid (SA) |
KNO3 (KN) “ g L-1 " |
|||||||||
None |
10 |
20 |
30 |
Mean |
None |
10 |
20 |
30 |
Mean |
|
Season1 |
Season2 |
|||||||||
Fruit set % |
||||||||||
None |
25.7 |
28.0 |
27.6 |
28.6 |
27.5 |
25.6 |
27.7 |
29.1 |
30.3 |
28.2 |
250mg/l |
29.3 |
31.0 |
33.6 |
32.3 |
31.6 |
26.0 |
31.3 |
32.3 |
32.0 |
30.4 |
500mg/l |
29.3 |
33.2 |
33.6 |
33.9 |
32.5 |
29.7 |
33.5 |
34.1 |
32.8 |
32.5 |
1000mg/l |
30.9 |
36.7 |
36.2 |
37.2 |
35.3 |
31.3 |
34.7 |
35.1 |
35.2 |
34.1 |
Mean |
28.8 |
32.2 |
32.8 |
33.0 |
|
28.1 |
31.9 |
32.7 |
32.5 |
|
LSD0.05 |
S=0.98, KN =0.98, S× KN =1.96 |
S=0.79, KN =0.79, S× KN =1.57 |
||||||||
|
Fruit weight(g) |
|||||||||
None |
2.98 |
3.23 |
3.21 |
3.19 |
3.15 |
2.88 |
2.88 |
2.99 |
2.96 |
2.93 |
250mg/l |
3.10 |
3.21 |
3.40 |
3.49 |
3.30 |
3.10 |
3.55 |
3.65 |
3.77 |
3.52 |
500mg/l |
3.50 |
3.69 |
3.79 |
3.72 |
3.68 |
3.52 |
3.89 |
3.86 |
3.95 |
3.80 |
1000mg/l |
3.70 |
3.82 |
3.92 |
3.93 |
3.84 |
3.64 |
3.95 |
3.93 |
3.92 |
3.86 |
Mean |
3.32 |
3.49 |
3.58 |
3.58 |
|
3.29 |
3.57 |
3.61 |
3.65 |
|
LSD0.05 |
S=0.076, KN =0.076, S× KN =0.151 |
S=0.116, KN =0.116, S× KN =0.232 |
||||||||
|
yield/tree (kg) |
|||||||||
None |
8.90 |
9.43 |
9.87 |
10.23 |
9.61 |
9.06 |
9.77 |
10.52 |
10.47 |
9.96 |
250mg/l |
9.46 |
10.34 |
10.99 |
11.32 |
10.53 |
9.66 |
10.99 |
11.32 |
11.17 |
10.78 |
500mg/l |
9.73 |
11.47 |
11.34 |
11.57 |
11.03 |
10.22 |
11.96 |
11.53 |
11.77 |
11.37 |
1000mg/l |
11.41 |
12.27 |
12.46 |
12.41 |
12.14 |
10.77 |
11.92 |
12.27 |
12.30 |
11.82 |
Mean |
9.88 |
10.88 |
11.17 |
11.38 |
|
9.93 |
11.16 |
11.41 |
11.43 |
|
LSD0.05 |
S=0.294, KN =0.294, S× KN =0.589 |
S=0.208, KN =0.208, S× KN =0.416 |
In addition, as shown in Table 4 and Fig.3, it can be concluded that all the studied yield parameters can be arranged according their affecting by the foliar sprays of SA, KN and their interaction as follows: fruit set% > fruit yield (kg/tree) > fruit weight
These results are in agreement with these obtained by 16,17,12,13,15,10.
The obtained results recorded the effect of potassium nitrate application on fruit set and yield are in harmony with the findings of 24on date palm cultivar "Zaghloul", 26 on date palm cultivar "Khalas", 30on date palm cultivar " Bartamoda" and 57 on date palm cultivar "Khalas".
The enhancement effect of SA on mitigated effect of salinity on fruit yield/tree of Manzanillo olive tree may be attributed to the increase of vegetative growth parameters especially total chlorophyll content which leads to more carbohydrates production through photosynthesis process and increasing vegetative growth and finally improved fruit yield. Also, SA have beneficial effect on enhancing organic matter, lowering soil pH as well as increased the uptake of water and nutrients 58,59 and enhanced soil fertility 60, 61.
Fig.3: Average increase percentages for some yield parameters of Manzanillo olives in both studied seasons (the highest significant treatment compared with the none treated)
The enhancement effect of potassium nitrate on mitigated effect of salinity on fruit yield may be attributed to that potassium reduces the excess uptake of ions such as sodium under saline stress. Generally, potassium plays an important role in controlling cell water content and carbohydrates biosynthesis and mobilization in plant tissues, consequently carbohydrates play a serious role in fruit set.
3.3. Fruit physical and chemical properties:-
a. Fruit physical properties
Results in Table 5 indicate that under salt stress conditions application of SA and KN separate or combined gave positive effects. The highest rate of SA caused average increases (for both seasons) of 28.9, 27.5 and 15.4% for fruit length (cm), fruit width (cm) and fruit volume (cm3), respectively. The highest rate of KN gave average increase of 14.1, 13.4 and 11.3% for fruit length (cm), fruit width (cm) and fruit volume (cm3), respectively.
Combination of 1000 mg KNL-1 with 30g SAL-1 gave an average increase in fruit length (cm), fruit width (cm) and fruit volume (cm3) of 44.1, 37.6, and 21.6%, respectively, for both seasons.
Data presented in Table 5 indicated that the different foliar application treatments significantly improved the studied fruit physical parameters i.e. fruit length (cm), fruit width (cm) and fruit volume (cm3) of Manzinello olive trees that are cultivated under salinity stress conditions in the following arrange, interaction of Salicylic acid + potassium nitrate > Salicylic acid > potassium nitrate, (Fig. 4).
Moreover, as shown in Table 5 and Fig 4, it can be concluded that all the studied fruit physical parameters can be arranged according their affecting by the foliar sprays of SA, KN and their interaction as follows: fruit width (cm) > fruit length (cm) > fruit volume (cm3)
Table5: Effect of salicylic acid and potassium nitrate foliar application on some fruit physical properties Manzanillo olives.
Salicylic Acid (SA) |
KNO3 (KN) “ g L-1 " |
|||||||||
None |
10 |
20 |
30 |
Mean |
None |
10 |
20 |
30 |
Mean |
|
Season1 |
Season2 |
|||||||||
Fruit length(cm) |
||||||||||
None |
1.790 |
1.850 |
1.833 |
1.903 |
1.844 |
1.693 |
1.780 |
1.737 |
1.680 |
1.723 |
250mg/l |
1.803 |
1.943 |
2.023 |
2.070 |
1.960 |
1.647 |
1.820 |
1.883 |
1.997 |
1.837 |
500mg/l |
1.977 |
1.983 |
1.960 |
2.067 |
1.997 |
1.723 |
2.280 |
2.273 |
2.353 |
2.158 |
1000mg/l |
1.990 |
2.08 |
2.193 |
2.310 |
2.143 |
2.343 |
2.363 |
2.363 |
2.693 |
2.441 |
Mean |
1.890 |
1.964 |
2.003 |
2.088 |
|
1.852 |
2.061 |
2.064 |
2.181 |
|
LSD0.05 |
SA=0.041, KN =0.041, SA× KN =0.082 |
SA=0.127, KN =0.127, SA× KN =0.254 |
||||||||
|
Fruit width(cm) |
|||||||||
None |
1.313 |
1.370 |
1.347 |
1.427 |
1.364 |
1.267 |
1.300 |
1.333 |
1.300 |
1.300 |
250mg/l |
1.320 |
1.527 |
1.500 |
1.577 |
1.481 |
1.333 |
1.467 |
1.500 |
1.500 |
1.450 |
500mg/l |
1.420 |
1.613 |
1.620 |
1.693 |
1.587 |
1.467 |
1.567 |
1.633 |
1.700 |
1.592 |
1000mg/l |
1.620 |
1.753 |
1.797 |
1.817 |
1.747 |
1.500 |
1.667 |
1.700 |
1.733 |
1.650 |
Mean |
1.418 |
1.566 |
1.566 |
1.628 |
|
1.392 |
1.500 |
1.542 |
1.558 |
|
LSD0.05 |
SA=0.015, KN =0.015, SA× KN =0.030 |
SA=0.082, KN =0.082, SA× KN =0.164 |
||||||||
|
Fruit volume |
|||||||||
None |
3.50 |
3.50 |
3.52 |
3.51 |
3.51 |
3.40 |
3.60 |
3.78 |
3.73 |
3.63 |
250mg/l |
3.19 |
3.52 |
3.60 |
3.71 |
3.51 |
3.40 |
3.89 |
4.00 |
4.21 |
3.88 |
500mg/l |
3.25 |
3.90 |
3.90 |
4.20 |
3.81 |
4.24 |
3.90 |
4.12 |
4.18 |
4.11 |
1000mg/l |
3.77 |
4.24 |
4.16 |
4.20 |
4.09 |
3.96 |
4.22 |
4.24 |
4.19 |
4.15 |
Mean |
3.43 |
3.79 |
3.80 |
3.90 |
|
3.75 |
3.90 |
4.04 |
4.08 |
|
LSD0.05 |
SA=0.08, K=0.08, SA×K=0.15 |
SA=0.08, KN =0.08, SA× KN =0.15 |
Fig.4: Average increase percentages for some physical properties of fruit Manzanillo olives in both studied seasons (the highest significant treatment compared with the none treated)
b. Fruit chemical properties
The obtained data in Table 6 indicate that under salt stress conditions application of SA and KN separate or combined gave positive effects. The highest rate of SA caused average increases (for both seasons) of 6.7 and 27.5% for TSS (%) and flesh oil content (%), respectively. It caused average decreases of -35.2% for total acidity (%). The highest rate of KN gave average increase of 5.4 and 13.6% for TSS (%) and flesh oil content (%), respectively. It caused average decreases of -6.8% for total acidity (%).
Combination of 1000 mg KNL-1 with 30g SAL-1 gave an average increase in TSS (%) and flesh oil content (%) of 10.9 and 44.5%, respectively, for both seasons. It caused average decreases of -35.2% for total acidity (%).
Table 6: Effect of salicylic acid and potassium nitrate foliar application on some fruit chemical properties of Manzanillo olives.
Salicylic Acid (SA) |
KNO3 (KN) “ g L-1 " |
|||||||||
None |
10 |
20 |
30 |
Mean |
None |
10 |
20 |
30 |
Mean |
|
Season1 |
Season2 |
|||||||||
T.S.S. (%) |
||||||||||
None |
10.78 |
10.86 |
10.78 |
10.75 |
10.80 |
10.72 |
10.80 |
10.54 |
10.77 |
10.71 |
250mg/l |
10.93 |
10.83 |
11.04 |
11.02 |
10.96 |
10.38 |
10.89 |
11.08 |
10.90 |
10.81 |
500mg/l |
10.69 |
11.49 |
11.57 |
11.51 |
11.32 |
10.66 |
11.53 |
11.57 |
11.51 |
11.32 |
1000mg/l |
10.79 |
11.48 |
11.81 |
11.92 |
11.50 |
10.70 |
11.48 |
11.74 |
11.92 |
11.46 |
Mean |
10.80 |
11.17 |
11.30 |
11.30 |
|
10.62 |
11.18 |
11.23 |
11.27 |
|
LSD0.05 |
SA=0.160, K=0.160, SA×K=0.321 |
SA=0.197, K=0.197, SA× KN =0.393 |
||||||||
|
Flesh oil content (%) |
|||||||||
None |
12.90 |
12.66 |
12.96 |
14.27 |
13.20 |
12.80 |
14.24 |
14.27 |
15.50 |
14.20 |
250mg/l |
14.80 |
14.53 |
15.20 |
15.41 |
14.99 |
14.86 |
15.26 |
15.96 |
16.57 |
15.66 |
500mg/l |
15.83 |
16.26 |
15.84 |
16.47 |
16.10 |
15.13 |
17.31 |
17.98 |
18.23 |
17.16 |
1000mg/l |
15.74 |
17.02 |
17.16 |
18.17 |
17.02 |
15.70 |
18.42 |
18.50 |
18.96 |
17.90 |
Mean |
14.82 |
15.12 |
15.29 |
16.08 |
|
14.62 |
16.31 |
16.68 |
17.32 |
|
LSD0.05 |
SA=0.67, KN =0.67, SA× KN =1.33 |
SA=0.45, KN =0.45, SA× KN =0.90 |
||||||||
|
Total acidity (%) |
|||||||||
None |
0.467 |
0.463 |
0.557 |
0.453 |
0.485 |
0.463 |
0.463 |
0.460 |
0.453 |
0.460 |
250mg/l |
0.443 |
0.430 |
0.433 |
0.417 |
0.431 |
0.457 |
0.427 |
0.430 |
0.410 |
0.431 |
500mg/l |
0.377 |
0.367 |
0.337 |
0.330 |
0.353 |
0.387 |
0.357 |
0.327 |
0.330 |
0.350 |
1000mg/l |
0.313 |
0.310 |
0.300 |
0.303 |
0.307 |
0.310 |
0.310 |
0.300 |
0.300 |
0.305 |
Mean |
0.400 |
0.393 |
0.407 |
0.376 |
|
0.404 |
0.389 |
0.379 |
0.373 |
|
LSD0.05 |
SA=0.036, KN =0.036, SA× KN =0.072 |
SA=0.014, KN =0.014, SA× KN =0.027 |
The obtained results of SA application regarding their positive effect on fruit physical and chemical properties are in harmony with the findings of 13,14,15. Using salicylic acid was very effective in enhancing yield and fruit quality of different fruit crops. Salicylic acid (SA) is considered as a hormone-like substance, which plays an important role in the regulation of plant growth and development, seed germination, fruit yield, rooting of cuttings and resistance to abiotic stresses 16,17,62 on "Bartamuda" date palm 63on date palm cultivars "Sewy", "Zaghloul" and "Hayany" and 10 on Valencia orange.
The enhancement effect of SA application on alleviating the detrimental effect of salinity stress on fruit physical and chemical properties may be due to increasing vegetative growth parameters especially total chlorophyll content which leads to more carbohydrates production through photosynthesis process and increasing vegetative growth and consequently improved flowering characteristics, fruit set percentage, fruit set and yield and finally improved fruit physical and chemical properties.
The enhancement effect of potassium nitrate application on alleviating the negative effect of salinity on fruit physical and chemical properties may be due to that potassium has an essential role in photosynthesis and osmo regulatory34, and it is required for physiological processes such as activation of enzymes, regulation of osmotic pressure and stomata movement35. As well as, it activates the enzymes involved in sugar biosynthesis and helps in translocation of sugars23. Moreover, potassium shows an important role in controlling cell water content and carbohydrates biosynthesis and mobilization in plant tissues.
The obtained results regarding the effect of potassium nitrate application on fruit physical and chemical properties go in line with the findings of 24on date palm cultivar "Zaghloul"; 25 on date palm cultivar "Khalas"; 26 on date palm cultivar "Khalas"; 30on date palm cultivar " Bartamoda"; 57 on date palm cultivar "Khalas"; 31 on "Valencia" orange and 32 on "Hayany" date palm and 10 on Valencia orange.
3.4. Leaf nutrients uptake
Data presented in Table 7 indicated that all nutrients uptake in leaf of Manzanello olives that cultivated under salt stress conditions were significantly increased with the increasing of foliar application rates of SA and KN when they were sprayed either single or in a combinations. Results in Table 7 show that all tested foliar sprays of salicylic acid (SA) were significantly increased the understudied leaf nutrients uptake with superiority for sprayed olive trees by 1000mgSA/l as compared with the other sprayed treatments in both seasons.
Table 7: Effect of salicylic acid and potassium nitrate foliar application on nutrients uptake by leaf of Manzanillo olives.
Salicylic Acid (SA) |
KNO3 (KN) “ g L-1 " |
|||||||||
None |
10 |
20 |
30 |
Mean |
None |
10 |
20 |
30 |
Mean |
|
Season1 |
Season2 |
|||||||||
N (mg/leaf) |
||||||||||
None |
6.23 |
6.38 |
6.35 |
6.44 |
6.35 |
6.29 |
6.62 |
6.92 |
7.05 |
6.72 |
250mg/l |
6.47 |
6.71 |
6.95 |
6.95 |
6.77 |
6.70 |
7.42 |
7.67 |
7.78 |
7.39 |
500mg/l |
6.61 |
7.22 |
7.56 |
7.82 |
7.30 |
7.27 |
7.97 |
8.03 |
8.22 |
7.87 |
1000mg/l |
7.80 |
7.95 |
8.63 |
9.73 |
8.53 |
7.56 |
8.32 |
8.78 |
10.07 |
8.68 |
Mean |
6.78 |
7.07 |
7.37 |
7.73 |
|
6.96 |
7.58 |
7.85 |
8.28 |
|
LSD0.05 |
SA=0.261, K=0.261 , SA×K=0.017 |
SA=0.252, K=0.252 , SA×K=0.016 |
||||||||
|
P (mg/leaf) |
|||||||||
None |
0.86 |
1.00 |
0.99 |
1.02 |
0.97 |
0.89 |
0.96 |
1.02 |
1.06 |
0.98 |
250mg/l |
1.04 |
1.06 |
1.13 |
1.16 |
1.10 |
1.03 |
1.12 |
1.19 |
1.25 |
1.15 |
500mg/l |
1.01 |
1.22 |
1.25 |
1.33 |
1.20 |
1.22 |
1.38 |
1.44 |
1.46 |
1.38 |
1000mg/l |
1.34 |
1.40 |
1.58 |
1.80 |
1.53 |
1.26 |
1.47 |
1.56 |
1.83 |
1.53 |
Mean |
1.06 |
1.17 |
1.24 |
1.33 |
|
1.10 |
1.23 |
1.30 |
1.40 |
|
LSD0.05 |
SA= 0.056, K=0.056 , SA×K=0.006 |
SA=0.053, K=0.053 , SA×K=0.007 |
||||||||
|
K (mg/leaf) |
|||||||||
None |
2.52 |
2.46 |
2.60 |
2.79 |
2.60 |
2.67 |
2.89 |
3.01 |
3.13 |
2.93 |
250mg/l |
2.63 |
3.18 |
3.27 |
3.45 |
3.13 |
2.76 |
3.27 |
3.39 |
3.52 |
3.24 |
500mg/l |
2.97 |
3.69 |
3.72 |
3.79 |
3.54 |
3.36 |
3.47 |
3.82 |
3.97 |
3.66 |
1000mg/l |
3.46 |
4.03 |
4.39 |
4.81 |
4.17 |
3.49 |
4.00 |
4.22 |
4.93 |
4.16 |
Mean |
2.90 |
3.34 |
3.49 |
3.71 |
|
3.07 |
3.41 |
3.61 |
3.89 |
|
LSD0.05 |
SA=0.151, K=0.151 , SA×K= 0.014 |
SA=0.134, K=0.134 , SA×K= 0.011 |
||||||||
|
Fe µg/leaf |
|||||||||
None |
72.3 |
72.7 |
72.6 |
74.4 |
73.0 |
70.5 |
73.0 |
76.1 |
77.1 |
74.2 |
250mg/l |
74.4 |
76.3 |
79.4 |
80.0 |
77.5 |
73.8 |
76.6 |
79.0 |
80.9 |
77.6 |
500mg/l |
78.1 |
80.4 |
82.2 |
84.3 |
81.3 |
75.9 |
80.7 |
82.8 |
83.6 |
80.8 |
1000mg/l |
77.3 |
84.0 |
91.6 |
100.7 |
88.4 |
77.5 |
84.5 |
89.3 |
102.5 |
88.4 |
Mean |
75.5 |
78.3 |
81.3 |
84.7 |
|
74.4 |
78.7 |
81.7 |
85.8 |
|
LSD0.05 |
SA=2.86, K=2.86 , SA×K=0.131 |
SA=2.68, K=2.68 , SA×K=0.13 |
||||||||
|
Mn µg/leaf |
|||||||||
None |
14.1 |
14.3 |
14.5 |
14.8 |
14.4 |
14.6 |
15.4 |
15.6 |
16.1 |
15.4 |
250mg/l |
14.3 |
15.8 |
16.4 |
17.0 |
15.9 |
15.6 |
16.0 |
17.2 |
17.7 |
16.6 |
500mg/l |
15.7 |
17.2 |
17.7 |
18.2 |
17.2 |
17.2 |
17.7 |
18.3 |
18.9 |
18.0 |
1000mg/l |
16.7 |
18.7 |
20.5 |
22.4 |
19.6 |
17.2 |
19.1 |
20.5 |
23.4 |
20.1 |
Mean |
15.2 |
16.5 |
17.2 |
18.0 |
|
16.2 |
17.0 |
17.9 |
19.0 |
|
LSD0.05 |
SA=0.632, K=0.632 , SA×K=0.075 |
SA=0.658, K= 0.658 , SA×K=0.063 |
||||||||
|
Zn µg/leaf |
|||||||||
None |
22.4 |
23.2 |
23.2 |
23.3 |
23.0 |
22.6 |
23.2 |
25.9 |
25.7 |
24.3 |
250mg/l |
23.1 |
26.1 |
26.9 |
27.2 |
25.8 |
26.1 |
27.4 |
27.6 |
28.1 |
27.3 |
500mg/l |
26.0 |
26.1 |
27.1 |
28.1 |
26.8 |
27.5 |
28.5 |
29.4 |
29.1 |
28.6 |
1000mg/l |
25.5 |
29.0 |
31.8 |
34.9 |
30.3 |
27.5 |
29.8 |
31.9 |
37.5 |
31.7 |
Mean |
24.2 |
26.1 |
27.2 |
28.2 |
|
25.9 |
27.2 |
28.6 |
29.9 |
|
LSD0.05 |
SA=1.14, K=1.14 , SA×K=0.08 |
SA=1.22, K= 1.22 , SA×K=0.082 |
Data presented in Table7 indicate that under salt stress conditions application of SA and KN separate or combined gave positive effects. The highest rate of SA caused average increases (for both seasons) of 31.7, 56.9, 51.2, 20.1, 33.3 and 31.3% for N (mg/leaf), P (mg/leaf), K (mg/leaf), Fe (µg/leaf), Mn (µg/leaf) and Zn (µg/leaf), respectively. The highest rate of KN gave average increase of 16.5, 26.4, 27.3, 13.8, 17.9 and 16.0% for N (mg/leaf), P (mg/leaf), K (mg/leaf), Fe (µg/leaf), Mn (µg/leaf) and Zn (µg/leaf), respectively.
Combination of 1000 mg KNL-1 with 30g SAL-1 gave an average increase in N (mg/leaf), P (mg/leaf), K (mg/leaf), Fe (µg/leaf), Mn (µg/leaf) and Zn (µg/leaf),of 58.1, 107.5, 87.8, 42.3, 59.6 and 60.9%, respectively, for both seasons.
From the aforementioned results it can be concluded that the different foliar application treatments significantly improved the studied nutrients uptake by leaf of Manzinello olive trees that are cultivated under salinity stress conditions in the following arrange, interaction of Salicylic acid + potassium nitrate > Salicylic acid > potassium nitrate, (Fig. 5).
.
Fig.5: Average increase percentages for nutrients uptake in leaf of Manzanillo olives in both studied seasons (the highest significant treatment compared with the none treated)
In addition, as illustrated in Fig.5, it can be concluded that all the studied nutrients uptake by leaf of Manzanillo olives can be arranged according their affecting by the foliar sprays of SA, KN and their interaction as follows: P (mg/leaf) > K (mg/leaf) > Zn (µg/leaf) > Mn (µg/leaf) > N (mg/leaf) > Fe (µg/leaf). This ascending order mean that the effect of foliar application of salicylic acid and KNO3 was more pronounced on the nutrients uptake by leaf of Manzanillo olives especially that are concerned with photosynthesis (e.g. P, K, Zn and Mn) and that represent an important role in formation of fruit biochemical contents. So this is reflected on the fruit quality and productivity of Manzanillo olives that grown under salt stress conditions. These results are accordance with those obtained by 27,31, 9
References
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