EFFECT OF ALKALINITY IN IRRIGATION WATER ON SELECTED GREENHOUSE CROPS A

292 Pages·2004·2.73 MB·English

EFFECT OF ALKALINITY IN IRRIGATION WATER ON SELECTED
GREENHOUSE CROPS

A Dissertation
by
LUIS ALONSO VALDEZ AGUILAR

Submitted to the Office of Graduate Studies of
Texas A&M University
in partial fulfillment of the requirements for the degree of

DOCTOR OF PHILOSOPHY

August 2004

Major Subject: Horticulture
EFFECT OF ALKALINITY IN IRRIGATION WATER ON SELECTED
GREENHOUSE CROPS

A Dissertation
by
LUIS ALONSO VALDEZ AGUILAR

Submitted to Texas A&M University
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Approved as to style and content by:

David Wm. Reed

(Chair of Committee)

H. Brent Pemberton Frank M. Hons
(Member) (Member)

Raul I. Cabrera Tim Davis

(Member) (Head of Department)

August 2004
Major Subject: Horticulture
iii
ABSTRACT

Effect of Alkalinity in Irrigation Water on Selected Greenhouse Crops. (August 2004)
Luis Alonso Valdez Aguilar, B.S., Universidad Autónoma de Nuevo León, Mexico;
M.S., Universidad Autónoma Chapingo, Mexico
Chair of Advisory Committee: Dr. David Wm. Reed

Bicarbonate (HCO -) and carbonate (CO 2-) are the most important ions that
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determine alkalinity. When the carbonates accumulate in a growing medium, the
growing medium solution pH reaches levels that cause plant growth inhibition, which is
caused primarily by the transformation of soluble forms of Fe into insoluble forms.
The general objective of this research was to provide information about the
limits of tolerance to alkalinity in ornamental plants, and to study the interaction of ions
such as ammonium (NH +) and nitrate (NO -) on the response of plants to alkalinity, as
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well as the effect of the counter-ions potassium (K+), sodium (Na+), cesium (Cs+),
ammonium (NH +) and rubidium (Rb+).
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The maximum SPAD index was estimated to occur at 0 mM of NaHCO in
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chrysanthemum, mini-rose, and hibiscus ‘Bimini Breeze’ and ‘Mango Breeze’. For
vinca it was set at 2.64 mM. A 15% decrease from the maximum SPAD index was
considered the threshold to declare the toxic concentration of NaHCO , which was
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calculated based on the maximum SPAD index predicted by the models.
The toxic concentration of NaHCO was set at 4.1, 1.1, 6.7, 3.1, and 6.3 mM of
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NaHCO in chrysanthemum, mini-rose, vinca, and hibiscus ‘Mango Breeze’ and
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‘Bimini Breeze’, respectively. Hibiscus ‘Bimini Breeze’ was considered tolerant to
alkalinity, due to increased Fe-reduction capacity and acidification of the growing
medium.
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In the hydroponic experiment, results showed that the NH +:NO - ratio altered
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the response of sunflower plants to alkalinity. Sunflower plants grew better in solutions
containing 5 mM NaHCO prepared with a 0.25:0.75 NH +:NO - ratio. This was
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possible due to the reaction of NH + with the HCO -, which reduced its buffering
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capacity.
The response to HCO --induced alkalinity was modified by the counter-cation
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of HCO -. In bean plants, at low-to-intermediate levels of Na+ and HCO - induced
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approximately same growth decrease. At high concentration, Na+ induced a decrease
on shoot growth that exceeded the toxic effects of HCO -. Thus, the toxic effect of Na+
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is higher than that of HCO - when its concentration is high. Rubidium was extremely
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toxic at concentrations of 7.5 mM.
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DEDICATION

I dedicate this dissertation to Juany, my wife, and Anakaren, my daughter. You
girls have always been there for me, and you know I have you both deep in my mind
and in my heart.
A very special dedication to my parents, Alonso and Angélica, for all they have
represented in my life: honesty, dignity, dedication, perseverance, love, and religion.
This dissertation is also dedicated to my extended family: brothers and sisters,
nieces and nephews. I also dedicate this dissertation to Rebeca, my mom in law, and all
my numerous in-laws.
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ACKNOWLEDGEMENTS

I express my utmost gratitude to Dr. David Wm. Reed. Certainly his guidance
determined the academic formation I received at Texas A&M University. His support
and understanding at the beginning of my studies gave me the time I needed to get
established in a country that looked so different than what I was used to. During
difficulties, I know his intervention was important for me to overcome hard times.
I am also grateful to all my committee members: Dr. H. Brent Pemberton, Dr.
Raul I. Cabrera, and Dr. Frank M. Hons. Thanks for all the advice, the thorough review
of my proposal and dissertation, and the constructive criticism.
I thank Dr. Frank Hons for his permission to work in his laboratory to analyze
nutrient solutions.
My sincere gratitude goes to Matthew Kent, senior research assistant. Thanks
for the suggestions and for bringing up the experiments with mixtures to Dr. Reed’s
lab. I also thank you for your technical assistance in the experiments executed.
Thanks to Paul Greer and Dr. Chuanjiu He for the help to solve all my problems
with computers and hydroponic experiments.
Special thanks to Dr. Michael A. Arnold, Mr. Jim Johnson, and Dr. Richard
White for the support during the Fall of 2003, when all seemed to be over.
My gratitude also goes to Andrew Cartmill, Donita Bryan, Trisha Blessington,
Carrie Whitcher, Alejandro Alarcon, Alma Solis, and Lucila Carpio. Special thanks to
Laura and Jeremy Burton.
I express my gratitude to México, for the financial support through the National
Council of Science and Technology (CONACYT) and the Department of Fitotecnia of
the Universidad Autónoma Chapingo.
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TABLE OF CONTENTS

Page

ABSTRACT……………………………………………………………………… iii

DEDICATION…………………………………………………………………… v

ACKNOWLEDGEMENTS…………………………………………………........ vi

TABLE OF CONTENTS……………………………………………………....... vii

LIST OF TABLES..……………………………………………………………… xiii

LIST OF FIGURES...……………………………………………………………. xx

CHAPTER

I INTRODUCTION………………………………………………... 1

Alkalinity Levels in Texas Water………………………... 2
Chemistry of the Carbonates…………………………….. 2
Relationship between Alkalinity, HCO -, and pH……….. 7
3
Other Factors That Increase Alkalinity…………………... 7
Direct and Indirect Effects of Alkalinity on Plants………. 8
Leaf Chlorosis and Alkalinity……………………………. 9
Alkalinity and Irrigation Water in Greenhouse Crops….... 11

II LITERATURE REVIEW………………………………………… 12

Effect of HCO - on Plant Growth………….…………..… 12
3
Is There a Signal to Detect HCO - Stress?.......................... 14
3
Iron Uptake and Accumulation..…………………………. 14
Effect of HCO - on Tissue Concentration of Fe..... 14
3
Bicarbonate and Fe Chlorosis: the Chlorosis
Paradox…………………………………………... 15
Bicarbonate and Root and Leaf Apoplastic pH...... 16
Bicarbonate and Fe-Reduction Capacity….……... 17
Plant Responses to Fe Deficiency..………………………. 19
Strategy I…………………………………………. 19
Strategy II………………………………………… 20
Effect of HCO - on Plant Nutrition..……………………... 20
3
Nitrogen………………………………………….. 21
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CHAPTER Page

Potassium………………………………………… 21
Phosphorus……………………………………….. 21
Calcium…………………………………………... 22
Magnesium……………………………………….. 22
Zinc………………………………………………. 22
Other Micronutrients…………………………….. 23
Interaction between Sodium and Alkaline pH …..………. 23
Uptake of HCO - and CO by Roots……………………... 23
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III DETERMINATION OF TOLERANCE AND TOXICITY
ALKALINITY LIMITS IN SELECTED GREENHOUSE
ORNAMENTAL PLANTS………………………………………. 24

Introduction………………………………………………. 24
Materials and Methods…………………………………… 26
Results and Discussion…………………………………… 29
Chrysanthemum…………………………………... 29
Rose………………………………………………. 36
Vinca……………………………………………… 41
Hibiscus…………………………………………... 45
Conclusions………………………………………………. 53

IV RESPONSE OF TWO CULTIVARS OF HIBISCUS (Hibiscus
rosa-sinensis L. ) TO ALKALINITY IN IRRIGATION WATER... 54

Introduction………………………………………………. 54
Materials and Methods…………………………………… 54
Experiment 4.1. Determination of Tolerance and
Toxic Limits of Alkalinity of Hibiscus Grown in
Sphagnum Peat-Based Growing Medium….…….. 54
Experiment 4.2. Determination of Tolerance and
Toxic Limits of Alkalinity of Hibiscus Grown in
Hydroponics…………………...…………………. 56
Results……………………………………………………. 58
Experiment 4.1. Determination of Tolerance and
Toxic Limits of Alkalinity of Hibiscus Grown in
Sphagnum Peat-Based Growing Medium………... 58
Shoot growth…………………………. 58
Root growth………………………….. 64
Shoot:root ratio………………………. 64
Growing medium pH………………… 67
SPAD index………………………….. 67
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CHAPTER Page

Toxic concentrations of NaHCO ……. 67
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Experiment 4.2. Determination of Tolerance and
Toxic Limits of Alkalinity in Hibiscus in
Hydroponics……………………………………… 70
General appearance…………………... 70
Shoot growth…………………………. 70
Root growth………………………….. 70
Shoot:root ratio………………………. 74
Solution pH…………………………... 74
Fe-reductase activity…………………. 76
SPAD index……….…………………. 76
Discussion………………………………………............... 76
Shoot Growth..…………………………………... 76
Root Growth……………………………………... 80
Growing Medium and Solution pH………………. 81
SPAD Index and Fe-Reductase Activity................. 82
Conclusions………………………………………………. 83

V EFFECT OF NO - : NH + RATIO IN THE RESPONSE OF
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SUNFLOWER (Helianthus annuus L. ‘Big Smile’) TO
ALKALINITY IN HYDROPONICS……………………………. 84

Introduction………………………………………………. 84
Materials and Methods…………………………………… 85
Results……………………………………………………. 86
Solution pH………………………………………. 86
Shoot Height and Number of Leaves…….………. 88
Total and Root Dry Mass.………………………. 93
Shoot:Root Ratio.………………………………... 93
Discussion………………………………………………... 93
Effect of the NO - : NH + Ratio…………………. 93
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The Interaction of NaHCO and NO - : NH +
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Ratio……………………………………………… 97
Conclusions………………………………………………. 99

VI EFFECT OF COUNTER-IONS OF BICARBONATE ON
BEAN (Phaseolus vulgaris L.) ‘Poncho’ GROWN IN
HYDROPONICS………………………………………………… 100

Introduction………………………………………………. 100
Materials and Methods…………………………………… 104
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Page

Experiment 6.1. Effect of Mixtures of Na+, K+,
and NH + on the Response of Bean Plants to
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HCO -……………..……………………………… 104
3
Experiment 6.2. Effect of Mixtures of Na+, K+,
and Cs+on the Response of Bean Plants to HCO -. 105
3
Experiment 6.3. Effect of Mixtures of Rb+, K+,
and Na+on the Response of Bean Plants to HCO -. 108
3
Experiment 6.4. Effect of Mixtures of Rb+, K+,
and Na+on the Response of Bean Plants to HCO -. 111
3
Experiment 6.5. Response of Bean Plants to
Alkalinity Induced by NaHCO and KHCO …….. 111
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Experiment 6.6. Effect of the K+:Na+ Binary
Mixtures on the Response of Bean Plants to
HCO -…………………………………………….. 113
3
Results……………………………………………………. 117
Experiment 6.1. Effect of Mixtures of Na+, K+,
and NH + on the Response of Bean Plants to
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HCO -…………………………………………….. 117
3
Shoot and root mass..………………… 117
Models……..……………..….. 117
Pure blends (vertices).....……... 117
Coordinates (0% to 100%
blends)...……………………… 117
Binary blends (50%:50%
blends)………………………... 122
Optimization..……………..…. 122
Leaf growth…………………………... 122
Shoot:root ratio………………………. 125
Total chlorophyll…………………….. 125
Solution final pH…………………….. 127
Discussion……………………............ 127
Shoot growth…………………. 127
Root growth and total
chlorophyll concentration……. 130
Conclusions…………………………... 131
Experiment 6.2. Effect of Mixtures of Na+, K+,
and Cs+on the Response of Bean Plants to HCO -. 131
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Experiment 6.3. Effect of Mixtures of Rb+, K+,
and Na+on the Response of Bean Plants to HCO -. 132
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Shoot and root mass ……..…………... 132
0 mM HCO - …..……………... 132
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7.5 mM HCO - …..…………… 138
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