PART I POLYMORPHISM IN MACROCYSTIS INTEGRIFOLIA BORY IN RELATION TO WATER MOTION PART II CONTROL OF DIATOM CONTAMINATION IN FIELD CULTURE OF GAMETOPHYTIC AND EARLY SPOROPHYTIC PHASES IN THE LAMINARIALES by DANNY ROY PACE B.Sc. Dalhousie University, 1967 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in the Department of Botany We accept this thesis as conforming to the required standard. The University of British Columbia March, .1972 In presenting this thesis in partial fulfilment of the requirements for an advanced, degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of Jot The University of British Columbia Vancouver 8, Canada Date /0/9/74 ABSTRACT A field study in three parts was undertaken to investigate the relationships between the habit of Macrocystis integrifolia Bory and water movement. Morphological variation in time within populations was re• lated to seasonal changes in wind direction and speed. Four sites covering a wide range of exposures, yet characterized by essentially the same water properties were sampled throughout a period of one year. In this way valid comparisons could also be made between populations. The sites were all situated in the vacinity of Barn- field on the west coast of Vancouver Island, B.C. A spot sampling study was undertaken to determine whether the trends established in the above study apply consistently throughout the range of exposures covered by Macrocystis in loc• al waters. Samples were obtained from Ucluelet on Vancouver Island to Warren Island in southern Alaska. Through these studies several aspects of the habit were found to reflect the prevailing dynamic conditions to which the plant had been subjected throughout its development. A transplant study was carried out among the continuous sampling sites to establish the mechanism of response to dynamic conditions. Growth data obtained through the transplant study indicated that stipe elongation and blade initiation vary direct• ly with water movement. Growth of individual blades appears to be independent of this factor. The results of the transplant study supported by variations observed within plants and within populations with time strongly suggest that the mechanism of response is phenotypic plasticity. However, plants observed on the outer coast were, in some re spects, markedly distinct. Thus the possibility of a second mechanism operating under conditions of genetic isolation ha not been discounted. TABLE OF CONTENTS PART I Page ABSTRACT LIST OF TABLES LIST OF FIGURES ACKNOWLEDGMENTS INTRODUCTION 1 MATERIALS AND METHODS 6 CONTINUOUS SAMPLING STUDY Description of Sites 6 Qceanoqraphic Data 8 Frond Sampling and Measurement 8 SPOT SAMPLING STUDY 10 TRANSPLANT STUDY Methods 11 Description of Transplants 12 Evaluation of Plant Response 13 RESULTS 14 CONTINUOUS SAMPLING STUDY Changes Recorded in Time and Place 14 Stipe Diameter 14 Stipe Length 16 Distal Meristematic Region 16 Blades ; 17 Number in Relation to Stipe Length -17 Width of Mature Laminae . 17 Changes Recorded Only In Space 19 SPOT SAMPLING STUDY 20 TRANSPLANT STUDY 21 Growth of Primary Fronds 21 Growth of Laminae 22 Blades per Unit Length of Stipe 22 Lamina width 23 DISCUSSION 24 Stipe Diameter 24 Stipe Length 27 Distal Meristematic Region 27 Blades Number in Relation to Stipe Length 30 Width of Mature Laminae 30 Lamina Thickness 33 Spines . 34 Pneumatocysts 34 QUALITATIVE OBSERVATIONS 35 Holdfast 35 Sporophylls 36 THE ENTIRE PLANT 37 SUMMARY 38 FIGURES .. 41 TABLES 57 LITERATURE CITED 70 PART II FOLLOWS PAGE 72 AND IS NUMBERED SEPARATELY LIST OF FIGURES FIGURE Page 1 Measurements of wind direction and speed 41 (m.p.h.) taken throughout 1970 at Cape Beale atthe southeast entrance to Barkeley Sound 2a Coast of British Columbia and southern 42 Alaska showing sites visited throughout the spot sampling study. 2b Sites visited throughout the continuous 43 sampling study. 3 Near-surface temperature/salinity diagrams 44 based on measurements taken at the four Bamfield sites throughout August, 1970. 4 Variation with time of salinity and tempera- 45 ture at five meters in Bamfield Inlet throughout 1969 - 70. 5 The Wizard Islet transplant site following 46 the experiment. 6 Variation with time of mean stipe diameter 47 and length at the four continuous sampling sites throughout 1970. Maximum and minimum values are indicated be horizontal bars. 7 Recorded values of stipe diameter and length 48 for fronds collected throughout the continuous sampling study. A linear relationship is espressed graphically for three of the sampling sites. 8 Variation with time of the mean number of 49 terminal splits on fronds collected throughout the continuous sampling study. 9 Recorded values of blade number and stipe 50 length for fronds collected throughout the continuous sampling study. A linear relation• ship is expressed graphically for all sites. 10 Variation with time of the mean width of young 51 mature laminae on fronds collected throughout the continuous sampling study. 11 A badly deteriorated frond extended toward the 52 surface at Dixon Island. 12 Transplant study. Growth in length of primary 53,54 fronds. 13 A distal meristematic region of a plant from 55 Wizard Islet. 14 A distal meristematic region of a plant from 55 Hope Island. 15,16,17 56 Basal portions of laminae collected during the sampling studies. 18,19 Margins of laminae from an exposed and a 56 moderately exposed site. LIST OF TABLES TABLE Page 1 Descriptions of sites visited throughout 57,58 the spot sampling and continuous sampling studies. 2 Analysis of variance among the four contin- 59 uous sampling sites for width of young mature laminae. 3 Analysis of data obtained from sample blades 60,61 which were collected in the Bamfield region during April, May and June of 1970. 4 Measurements of fronds collected throughout the 62,63 spot sampling study. 5 Measurements of blades obtained throughout the 64,65 spot sampling study. 6 Growth of primary fronds and initiation rates 66 for laminae recorded throughout the transplant study. 7 Growth of laminae on plants involved in the 67 transplant study. 8 Transplant study. Variation with time of the 68 mean number of blades per meter of stipe for primary fronds. 9 Transplant study. Maximum width, in centimeters, 69 of mature laminae numbered from the base of the primary stipe. ACKNOWLEDGMENTS I wish to express my appreciation to the many persons who assisted me during this study. In particular I am grateful to my supervisor, Dr. R. F. Scagel, for his un• failing confidence and financial support. I am also grate• ful to my graduate committee, which also included Drs. K. Cole and R. Forman, for their assistance and criticism of the manuscript. Statistical analyses were carried out under the guidance of Mr. Steve Borden. Mr. Brenton Baillie assisted throughout the field studies. Mrs. Helen Styan aided in the collection of field data. Mr. Charles Collinson advised and assisted in the development of the in_ situ culture apparatus. I am also grateful for the many contributions of the following: Drs. Louis Druehl, Tony Chapman, Jim Markham, Peter Newroth and Mr. Ron Long. A special note of thanks to Miss Gwyn Kibble and Judy Murphy for their assistance in the preparation of the manuscript. -1- INTRODUCTION The purpose of this study was to investigate the relation• ships between polymorphism in the sporophyte of Macrocystis inteqrifolia Bory and varying degrees of water movement. Much attention has been paid to this question with respect to those members of the Laminariales other than the Lessoniaceae by several authors including Burrows (1958), Druehl (1967), Kain (1962, 1971), MacFarlane (1961), Norton (1969), Parke (1948) and . Sundene (1958, 1961a, 1961b, 1964). From these works a general pattern has emerged which can best be explained by considering a typical laminarialean plant consisting of a lamina, stipe and holdfast. Proceeding from a sheltered locality to one exposed to the direct force of the open sea, the lamina narrows and the tissues thicken, becoming tough yet flexible. The base of the lamina be- comes more cuneate and if the species is characterized by the formation of longitudinal splits these become more prominent, often being absent entirely from plants of the same species in quieter waters. The length of the lamina is a highly variable feature and is determined by all of the factors which contribute to terminal erosion as well as growth rate and age. Stipes from exposed sites are usually longer and smaller in diameter but are also stronger and more flexible. Parke (1948) treated in detail the subject of morphological variation with respect to the holdfast of Laminaria saccharina (Linnaeus) Lamour. However, she attributed the occurrence of different forms to the nature of the substratum rather than ex• posure. She noted that plants growing on solid substrates bore compact and thick holdfasts with slightly branched haptera where• as plants growing on soft silt had holdfasts with thin, long, copiously branched haptera. However, other features of the plants -2- used as examples along with the fact that turbulent waters sel• dom lend themselves to the accumulation of silt, strongly suggest that this effect was more closely related to exposure. Through transplant studies it has been demonstrated that, given the proper stimulus, individual plants are capable of as• suming a form appropriate to a particular set of environmental conditions. This type of response is termed "phenotypic plas^ ticity". Although certain aspects of the thallus of Macrocystis can be compared directly with the generalized laminarialean plant described above, there are features peculiar to this growth which set it apart and create new opportunities for morphological var• iation.