Jackson, WD

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PAPERS AND PROCEEDINGS OF THE ROYAL SOCIETY OF TASMANIA, VOLUME 92 CHROMOSOME NUMBERS IN TASMANIAN GOODENIACEAE AND BRUNONIACEAE By W. D. JACKSON Department oj Botany, University oj Tasmania (WITH 1 TEXT FIGURE) ABSTRACT Species of Goodenia, Velleia, Selliera and Scaevola have a basic chromosome number of ~, whilst Dampiera and Brunonia show a basic num-ber of 9. With the exception of Selliera radicans which has diploid and hexaploid races, all others are diploid. INTRODUCTION Thirteen members of the Goodeniaceae and the monotypic Brunonia australis have been recorded from Tasmania. None are endemic. Four species are rare or are doubtful records. Four are re-stricted in distribution, while the other five are common species with wide distributions. With the possible exception of the sub-herbaceous Goodenias, the Tasmanian members offer few taxonomic diffi-culties. The principle interest lies in the relation-ships between genera and the position of Brunonia which has in the past been grouped with the Goodeniaceae. At present there is no published account of chromosome numbers in this distinctive Australian group. However, P. Martin (University of Adelaide) is at present working on the Australian members. MATERIALS AND METHODS Only Tasmanian specimens were studied. Where possible material was obtained from different en-vironments and from a wide range in the Tas-manian distribution. Morphological variants com-mon in Goodenia humilis, G. elongata and G. lanata were investigated. Meiosis in pollen mother cells was studied using aceto-orcein and aceto-lacmoid smear methods (Darlington and La Cour, 1947). Root tips were used for the study of mitosis, both untreated and with treatments of aqueous solutions of para-dichlorobenzene (Meyer, 1945) before fixation in acetic-alcohol. Acetic stains were used for most of the investigation. Feulgen staining was tried, but no satisfactory stain intensity was obtained. OBSERVATIONS AND DISCUSSION A summary of the counts determined and the origin of the material is given in Table 1. Draw-ings of representative plates are provided in the text figure. In the Goodeniaceae the chromosome complement is surprisingly uniform in both number and mor-phology. Apart from Dampiera stricta with 2n = 18, the Tasmanian members investigated all have the diploid number 2n = 16, except in Selliera radicans where a hexaploid 2n = 48 was found in addition to the diploid form. There do not appear to be any significant morphological differences be-tween these two chromosome races, which were found in the same locality. The chromosome num-ber of Brunonia australis is 2n = 18. Meiosis was normal in all specimens and pollen fertility, as measured by stainable pollen, was high.' There is no evidence of apomixis in the members studied. The chromosomes are fairly small. In mitotic metaphase the chromosomes range from 2,5-4 '" in length. Mitotic plates are small and compact. Narrow meiotic spindles are a feature of the Goodeniaceae, with cross sectional areas 1/20th that of the pollen mother cell section. This feature while common to all species of the Goodeniaceae studied is not found in Brunonia australis. As mentioned above, the chromosome comple-ment in the Goodeniaceae is markedly uniform. Although Dampiera strict a has a haploid comple-ment of nine, studies of chromosome morphology indicate that eight of these are indistinguishable from the genome in other genera. All the chromo-somes are metacentric, with four shorter chromo-somes with a 5/4 arm ratio. One of the four long members has a 111 arm ratio while the ratio in the other three is approximately 3/2. The long arm of one of these has a prominent trabant. In Dampiera stricta the complement appears to be identical apart from the addition of another short chromosome with a 111 arm ratio. Martin (un-pub.) has found polyploid series based on x = 9 in mainland members of Leschenaultia and Dam-piera. Brunonia' australis appears to possess eight members similar to that in the eight mem-bered Goodeniaceae. There the additional mem-ber to the haploid set is a long chromosome with a 5/4 arm ratio and a heterochromatic segment near the distal end of the short arm. Practically all chiasmata are terminal or nearly so. In Brunonia the distal localization of chiasmata is most pronounced. Brunonia australis also differs from the members of the Goodeniaceae studied in having a larger cell size and a relatively larger spindle. With these exceptions the group appears to be homogeneous cytologically, based on x = 8 and x = 9, with some apparent uniformity in chromosome morphology. I wish to acknowledge the kind assistance of Mr. T. E. Burns in collecting material in Northern Tasmania. 1111 o~ ~ TABLE I Chromosome numbers oj Tasmanian Goodeniaceae and Brunoniaceae. n ;Ii ;u 0 ~ Collecting locality and Remarks Chromosome 0 en Species altitude number 0 ~ t"'l Z GOODENIACEAE 2n n t-:: Velleia, Sm. ~ 0; V. montana, Hook. f. King William Saddle 2,800 robust Ivs. 10 cm. 16' B liJ Interlaken 2,600 reduced lvs. 4-5 cm. 16 8 w V. paradoxa, R.Br. Springfield, Glenorchy 200 robust Ivs. 14 cm. glabrous 16 8 Z Georgetown 100 lvs. 7 cm. hairy entire ± 16 8 Goodenia, Sm. ,..;; :<-G. ovata, Sm. Tolosa St., Glenorchy 200 typical 16 8 en '" St. Marys 800 typical 16 ~< :<-G. amplexans, F.v.M. Not collected I Z G. barbata, R.Br. INot collected :;; G. geniculata, RBI'. I Not collected z G. lanata, RBI', Mt. Nelson 300 typical 16 8 g Murdunna 50 lvs. 3 cm. x 2·5 cm. 16 8 Low Head 50 lvs. 4 cm. x 1·5 cm. 16 to' t<i G. elongata, LabUl. St. Helens 50 hairy reduced 16 8 z Low Head 100 ± glabrous robust 16 8 :; G. humilis, RBI'. Low Head 20 typical Ivs. 3 cm. 16 8 0 Low Head 20 robust lvs. 5 cm. x 0'5 cm. 16 8 ~ Selliera, Cay. i:'J S. radicans, Cay. Glenorchy typical 16 8 ;,.. z Glenorchy typical 48 24 t::1 Scaevola, Linn. ~ S. hookeri, F.v.M. Mt. Wellington 4,000 reduced 16 8 "" c:: Collins Cap 1,900 robust 16 z Darnpiera, R.Bl'. 0 Z D. stricta, RBI'. Bicheno 50 typical 18 9 ;-;: n BRUNONIACEAE I Queechy Hill, Laun. I t"'l 50 ItYPical :<-Brunonia, Sm. ~ B. australis, Sm. 18 9 W. D. JACKSON REFERENCES DARLINGTON, C. D. AND LA COUR, L. F., 1947.-The Handling of Chromosomes. London, Allen and Unwin. MEYER, J. R., 1945.-Prefixing with Paradichlorobenzene to Facilitate Chromosome Study. Stain Technology, 20, 121-125. FIGURE 1 ~'\.. \ l~~ ••• / ''>' ~ .... r -II. E) 5. ~~~ ?v,~ '.' 6. f\ 12. J. 2. ·h'.! '~l. ~"';,I rl "tJI'lm$\\'" \~\\'(., < __ 't,,! " ,,~ 13. st., .. s. 3. ~ Side View Metaphase 1. Brunonia australis n == 9 2. Goodenia ovata n = 8 3. Selliera radicans n = 24 Polar View Metaphase II 4. Goodenia humilis n = 8 5. Velleia montana n = 8 6. Goodenia ovata n = 8 7. Dampiera stricta n =: 9 8. Selliera radicans n = 24. Polar View Mitotic Metaphase 9. Velleia montana 2n = 16 10. Goodenia lanata 2n = 16 11. Goodema elongata 2n = 16 12. Dampiera strieta 2n = 18 13. Seaevola hookeri 2n = 16 163 

Chromosome numbers in Tasmanian Goodeniaceae and Brunoniaceae

Dampiera stricta n =: 9

Handling of Chromosomes.

I rl &quot;tJI'lm$\\'&quot;

Selliera radicans n = 24. Polar View Mitotic Metaphase

Velleia montana n

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Chromosome numbers in Tasmanian Goodeniaceae and Brunoniaceae

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