The role of nutrient solution composition on the uptake of nutrients,

growth and vase life of tulips grown hydroponically under South African

conditionsGeline Derbyshire, Eleanor W Hoffman and Estelle Kempen

South African Journal of Plant and Soil 2015, 32(3): 129–137

01-Feb-201701-Feb-2017

- Dhriti SatyaProf. Dr. agr. sc. Margarethe Serek

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Introduction :

South Africa : Warm production region (≠ Tulip production)

Marketing!

Advantages-InfrastructureLaborAbundance natural resourcesEstablish export market through fynbos sector

Difficult to produce cut-tulip-Climatic conditionsExpensive climate controlProducers dependent on imported bulb

Tulip bulbs are importedSome are planted first in season => Early-forced bulb

and others are stored dry to plant later in season => Late-forced bulb

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Introduction :

Tulip bulb force to grow hydroponically

Soilless culture => Control root-zone environment (Nutrient management)

Assume to increase the tulip’s vase life, healthy scape and leaves and also flowering

Flowering depends on - Bulb fertility - Composition of growing medium - Use of supplementary nutrients

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Plant material

Standard Steiner solution(South Africa)

2 Bulb maturities4 commercial tulip cultivar

Belgium (Europe)

Amended solution(Europe + NH4+)

‘Leen van der Mark’ ‘Jan van Nes’, ‘Royal Virgin’ Ile de France

10-12cm

Materials and methods: :Nutrient solutions

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Plant material

60cm

40cm 10cm

X (12 forcing trays)

3 bulbs per cultivar per tray were randomly labeled.

48 bulbs were planted randomly in 12 forcing trays to represent 12 bulbs of each cultivar in a split-plot design.

Prior to harvest so as to eliminate bias - • Growth measurements• Postharvest evaluations• Nutrient analysis.

unlabelled, marketable plants were to be used in the vase-life studies

Materials and methods:

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TreatmentsIn glasshouse

1st -: In October 2012Performed immediately after arrival of the bulbs in South Africa (thus termed the early-forcing bulbs)

2nd -: In March 2013Bulbs stored dry for > 6 months were used (late forcing bulbs). These bulbs subsequently differed in their physiological age prior to rooting and forcing.

•EC of 1.6–1.8 mS/cm•pH 5.5–7.0• Replaced weekly

Four nutrient solutions

Current SA Standard Steiner Europe Europe + NH4+

+ micronutrients + micronutrients + micronutrients-

Materials and methods: :

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Rooting

Immediately after removal from storage

bulbs were rooted in forcing trays in a dark room at 3–4 °C

Nutrient flow

Bulb roots 3–5 cm in length; attained within3 weeks for early-forcing bulbs &1 week for late-forcing bulbs

Sensor

The EC and pH of the nutrient solutions were monitored throughout the rooting period and maintained. The nutrient solution was replaced weekly to prevent salinisation or depletion of nutrients

Materials and methods:

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Vegetative growth phase

The growth and development (expressedas plant height in mm) of three plants per cultivar per tray was recorded twice a week.

Rooted bulbs

Glasshouse(temperature 20 ± 2 °C,

relative humidity 55–65%)

Materials and methods:

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Harvest

Min 300mm + Color change

dry mass of eachplant (g) was recorded

stems were evaluated forstem length (mm),leaf area (cm2) andplant fresh mass (g)

X (10 bunches)of 8 flowers each per nutrient solution

vase-life testsRetail simulation

Materials and methods:

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Vase life

Evaluation of vase-life duration of each stem• degree of wilting• color loss of the tepals• toppling of the stem and• yellowing of the foliage. The day of first flower removal + 50% flower removal was recorded. Vase life was terminated when >60% of tepals on a particular flower were withered or a stem had toppled.

Materials and methods:

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Figure 1: Effect of various cultivars and bulb age on the first 11 d of scape growth (mm) of hydroponically forced cut tulips grown under warm climatic conditions

Significant cultivar growth differencesScape growth

With later harvest,• Cultivar emerge early• Rate of stem elongation increase• Sprouting increase• More response to vernalisation treatment

Results and discussion:

Scape length & Plant height non significant to different nutrient solutions.

12Figure 2: Effect of bulb age and cultivar on postharvest stem length (mm).

Stem length

Results and discussion:

21.7%longer More responsive to vernalisation

35%longer

Longer production † stem elongation

Stem length non significant to different nutrient solutions.

Post harvest parameters

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Treatment Leaf area (cm2)

Current SA 224.10

Standard Steiner

251.92

Europe 237.70

Europe + NH4+

230.72

F-value 3.07

p-value 0.03

Significance *

* p < 0.05

Results and discussion:

Table: Effect of (a) nutrient solution on leaf area of cut tulips grown hydroponically under warm climatic conditions.

Produced the largest leaf area

Post harvest parameters

N content of leaves Regulate photosynthesis

and stimulate leaf expansion

(b) CultivarsTwo cultivar had largest leaf area whereas two had smallest. Different cultivar respond differently to environmental factors

(c) BulbsEarly-forced bulb = 333.5 cm2

Late-forced bulb = 138.6 cm2 (also shorter stem)Leaf formation Initially by reserves in bulb, later by assimilates from leaves.Increases until senescence

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Figure: Interactions between (a) nutrient solution and bulb age (b) cultivar and bulb age on the fresh mass of cut tulips that were forced hydroponically under warm climatic conditions

lower Fresh Mass of late-forced bulbs Î t ∝to anthesis for the early-forced bulbs, and thus longer exposure to nutrition and the production of photosynthates. late-forced bulbs that were stored for alonger period than early-forced bulbs continue to respire at low rate during storage. Thus they have fewer reserves available for initial growth and emergence of leaves, which may have resulted in a smaller leaf area and thus less assimilates available for further growth of new organs. In turn this may have resulted in thedecreased FM for late-forced bulbs.

Results and discussion:

15Figure 4: Interactions between cultivar and bulb age on the dry mass of cut tulips grown hydroponically under warm climate conditions

Results and discussion:

Dry mass CHO (photosynthesis) 90% DM

*

*

*

Difference less expected Genetic cultivar differences

Early forced bulbs increased DM –longer time to flower (23 d w LFB 11d) bulbs Nutrients accumulation + CHO production over a longer period. duration of bulb chilling received

The DM - not significantly affected by the nutrient solution composition

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Figure: Interactions between (a) cultivar and bulb age and (b) nutrient solution and bulb age on the vase life of cut tulips grown hydroponically under warm climatic conditions

Vase life

Results and discussion:

Water stress terminate vase life EFB have higher transpiration rate

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Scape growth was not significantly influenced by applied nutrientsTulip bulb contains sufficient reserves.

Nutrition solution affected the leaf area of flowering stems Marketability

Nutrient solutions (Standard solution & Europe) Highest quality cut flower & longest vase life for all cultivar.

Leen van der Mark – longest stem Preferred for cut flower

Leen van der Mark should be promoted under warm conditions.

Early-forced bulb Longer stem, sig. leaf area, increased fresh and dry weight.Late-forced bulb Scape grew rapidly, longest vase life Quality

Optimized nutrient solution produce quality cut tulips, depending on the cultivar and physiological bulb age.

Conclusions:

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Geline Derbyshire, Eleanor W Hoffman and Estelle Kempen, 2015. The role of nutrient solution composition on the uptake of nutrients, growth and vase life of tulips grown hydroponically under South African conditions. South African Journal of Plant and Soil 2015, 32(3): 129–137.

Reference:

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Thank you for your attention!