Exploring intraspecific pollen morphology variation in Apocynaceae: A roadmap for horticultural innovation

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Qualitative traits of morpho-structure of pollinia_

Sr. No.	Apocynaceous taxa	Pollinium orientation	Pollinium shape	Sterile margins	Orientation of sterile margins	Translator attachment to pollinium	Corpuscular arm	Translator attachment to corpusculum	Colour of pollinia	Exine sculpturing
1.	Asclepias curassavica L.	Pendent	Narrowly oblong	Absent	Absent	Basal	Absent	Sub-apical	Brown	Psilate & Perforate
2.	Calotropis procera (Aiton) Dryand.	Pendent	Obovate	Absent	Absent	Basal	Absent	Sub-apical	Canary yellow	Psilate
3.	Leptadenia pyrotechnica (Forssk.) Decne.	Transverse	Orbicular	Present	Apical	Basal	Absent	Apical	Brown	Psilate
4.	Oxystelma esculentum (L. f.) Sm	Pendent	Narrowly oblong	Absent	Absent	Basal	Absent	Apical	Yellow	Perforate
5.	Pergularia daemia (Forssk.) Chiov.	Pendent	Obovate	Pseudo-sterile	Parallel	Basal	Absent	Apical	Pinkish Brown	Psilate, perforate
6.	Vincetoxicum spirale (Forssk.) D.Z.Li	Pendent	Narrowly oblong	Absent	Absent	Basal	Present	Apical	Golden	Psilate, perforate
7.	Dregea volubilis (L.f.) Benth. ex Hook.f	Erect	Reniform	Absent	Absent	Basal	Absent	Apical	Sulphur yellow	Perforate

Quantitative measurement of pollinia_

Sr. No.	Apocynaceous taxa	Length of pollinium Sac mean (min–max) SE (μm)	Breadth of pollinium Sac mean (min–max) SE (μm)	Length of translator mean (min–max) SE (μm)	Breadth of translator mean (min–max) SE (μm)	Length of corpusculum mean (min–max) SE (μm)	Breadth of corpusculum mean (min–max) SE (μm)
1.	Asclepias curassavica L.	209.60 (200.25–215.75) ± 1.62	82.70 (73.75–88.00) ± 0.44	90.05 (83.50–100.50) ± 2.85	23.25 (22.25–24.25) ± 0.35	89.25 (83.75–93.50) ± 1.64	33.25 (23.75–41.00) ± 2.800
2.	Calotropis procera (Aiton) Dryand.	315.81 (306.50–323.25) ± 0.48	129.44(128.25–130.50) ± 0.55	47.25 (41.25–51.25) ± 0.27	12.87(11.50–13.75) ± 0.48	90.93 (85.25–95.50) ± 0.61	56.68 (51.00–65.75) ± 0.20
3.	Leptadenia pyrotechnica (Forssk.) Decne.	46.30 (35.25–55.75) ± 0.82	33.35 (26.50–41.25) ± 0.19	7.25 (5.25–9.00) ± 0.66	7.75 (5.75–12.75) ± 0.26	16.80 (10.25–22.75) ± 0.02	13.40 (12.75–14.75) ± 0.35
4.	Oxystelma esculentum (L. f.) Sin	179.55 (81.25–98.32) ± 0.69	37.62 (40.23–35.02) ± 0.25	24.7 (23.15 +26.25) ± 0.82	8.75(8.3–9.2) ± 0.62	74.63 (78.36–70.92) ± 0.82	34.40 (32.26–36.55) ± 1.12
5.	Pergularia daemia (Forssk.) Chiov.	168.45 (159.00–178.00) ± 1.37	61.30 (55.25–71.50) ± 0.90	Absent	Absent	51.65 (46.00–54.00) ± 0.49	41.40 (32.00–60.75) ± 0.23
6.	Vincetoxicum spirale (Forssk.) D.Z.Li	74.55 (73.25–77.00) ± 0.73	47.65 (42.75–57.75) ± 0.70	21.55 (18.25–25.25) ± 1.36	21.45 (17.75–25.50) ± 0.33	75.85 (71.25–82.75) ± 0.14	37.40 (31.25–42.75) ± 0.82
7.	Dregea volubilis (L.f.) Benth. ex Hook.f	98.15 (58.25–117.25) ± 1.90	38.35 (32.00–43.25) ± 0.01	14.85 (12.25–18.00) ± 1.01	7.95 (7.25–8.75) ± 0.25	258.60 (244–270.50) x± 0.35	33.95 (17.75–56.25) ± 7.85

Quantitative findings of Apocynaceous pollen_

Sr. No.	Apocynaceous taxa	P/E ratio	Exine thickness mean (min–max) SE (μm)	Polar diameter mean (min–max) SE (μm)	Equatorial diameter mean (min–max) SE (μm)	Length of colpi mean (min–max) SE (μm)	Width of colpi mean (min–max) SE (μm)	Mesocolpium mean (min–max) SE (μm)
1.	Allamanda cathartica L.	0.99	1.95 (1.25–2.75) ± 0.26	30.1 (27.25–32.75) ± 0.89	30.25 (28.00–33.75) ± 0.95	13.65 (12.25–16.25) ± 0.70	6.05 (4.75–7.25) ± 0.48	21.60 (21.75–23.75) ± 0.74
2.	Alstonia scholaris (L.) R. Br.	0.86	3.10 (3.75–2.75) ± 0.18	20.75 (15.25–23.25) ± 0.51	23.40 (20.25–27.75) ± 0.30	5.30 (4.50–6.50) ± 0.34	4.80 (2.00–6.25) ± 0.72	21.95 (20.50–23.75) ± 0.62
3.	Carissa macrocarpa (Eckl.)A. DC.	0.99	3.20 (2.75–3.50) ± 0.14	36.80 (34.50–39.50) ± 0.89	36.95 (35.75–38.25) ± 0.46	3.00 (2.25–4.00) ± 0.34	5.50 (4.50–7.25) ± 0.48	35.85 (32.75–38.50) ± 0.07
4.	Carissa spinarum L.	0.92	3.35 (2.75–4.50) ± 0.32	24.30 (23.25–26.25) ± 0.55	26.35 (25.25–27.75) ± 0.46	2.8 (2.25–3.25) ± 0.16	2.25 (2.00–3.00) ± 0.18	20.55 (18.50–23.75) ± 0.93
5.	Cascabela thevetia (L.) Lippold	1.02	2.8(3.20–4.10) ± 0.28	113.45 (109.4–114.2) ± 0.8	109.20 (107.7–110.2) ± 0.40	5.20 (4.70–5.57) ± 0.13	15.20(15.30–15.20) ± 0.50	18.33 (17.50–19.25) ± 0.55
6.	Catharanthus roseus (L.) G. Don	0.98	4.85 (4.50–5.25) ± 0.37	56.45 (55.75–57.75) ± 0.89	57.30 (55.25–61.25) ± 0.38	13.60 (13.00–14.25) ± 0.48	6.50 (6.00–7.00) ± 0.395	44.25 (44.25–47.25) ± 0.379
7.	Cryptolepis dubia (Burm.f.) M.R. Almeida	0.74	1.35 (0.25–2.50) ± 0.43	20.30 (19.75–20.75) ± 0.16	27.10 (25.25–29.50) ± 0.78	Absent	Absent	Absent
8.	Nerium oleander L.	0.98	3.20 (2.75–3.75) ± 0.20	33.65 (32.00–35.75) ± 0.69	34.25 (33.25–37.00) ± 0.70	3.10 (1.25–4.25) ± 0.52	5.25 (4.00–6.00) ± 0.34	36.70 (33.75–38.50) ± 0.89
9.	Periploca aphylla Decne.	3.53	4.90 (4.50–5.50) ± 0.20	52.00 (49.50–55.25) ± 0.72	24.16 (21.25–26.00) ± 1.02	Absent	Absent	Absent
10.	Plumeria rubra L.	1.08	3.10 (2.75–3.50) ± 0.12	36.85 (31.00–40.25) ± 0.63	33.95 (29.50–37.00) ± 0.32	0.45 (0.25–0.75) ± 0.09	10.50 (10.25–10.75) ± 0.11	38.55 (38.00–39.50) ± 0.25
11.	Tabernaemontana divaricata (L.) R.Br. ex Roem. & Schult.	0.96	1.65 (0.75–2.25) ± 0.28	28.85 (28.25–30.50) ± 0.42	29.80 (27.75–32.75) ± 0.86	8.45 (2.75–10.75) ± 0.50	8.45 (2.75–10.75) ± 0.50	14.100 (13.25–15.25) ± 0.35

Checklist of Apocynaceous plants sampling and herbarium accession_

Sr. No.	Apocynaceous taxa	Flowering period	Voucher No.	Localities	Coordinates	Collector’s name	Accession No.	Altitude (feet)	District/province
1.	Allamanda cathartica L.	June to September	AC-01	Green town	32.576547° N, 71.575377° E	Rizwan & Salman	ISL-133416	688	Mianwali/Punjab
2.	Alstonia scholaris (L.) R. Br.	November to January	AS-16	Cantt.	31.513099° N, 74.373667° E	Rizwan	ISL-133415	712	Lahore/Punjab
3.	Asclepias curassavica L.	June to October	AC-32	Rawalpindi	33.567410° N, 73.085568° E	Rizwan	ISL-133428	1,680	Rawalpindi/Punjab
4.	Calotropis procera (Aiton) Dryand.	October to December	CP-06	Mirpur	25.514458° N, 69.023728° E	Rizwan & Prem	ISL-133431	60	Mirpur/Sindh
5.	Carissa macrocarpa (Eckl.) A. DC.	October to November	CM-15	Chakwal	32.939325° N, 72.864004° E	Rizwan	ISL-133422	1,965	Chakwal/Punjab
6.	Carissa spinarum L.	July to August	CS-10	Rumli	33.752956° N, 73.136338° E	Rizwan & Prem	ISL-133426	2,346	Islamabad
7.	Cascabela thevetia (L.) Lippold	June to October	CT-11	ICT	33.745615° N, 73.137888° E	Rizwan & Prem	ISL-133418	2,031	Islamabad
8.	Catharanthus roseus (L.) G. Don	July to August	CR-03	QAU	33.745623° N, 73132074° E	Rizwan	ISL-133419	2,031	Islamabad
9.	Cryptolepis dubia (Burm.f.) M.R.Almeida	June to August	CD-13	Sakesar	32.541652° N, 71.934362° E	Rizwan	ISL-133430	4,960	Khushab/Punjab
10.	Leptadenia pyrotechnica (Forssk.) Decne.	July to September	LP-09	Namal	32.668914° N, 71.614760° E	Rizwan & Salman	ISL-133425	1,129	Mianwali/Punjab
11.	Nerium oleander L.	July to September	NO-12	Talagang	32.913338° N, 72.426670° E	Rizwan	ISL-133424	1,666	Talagang/Punjab
12.	Oxystelma esculentum (L. f.) Sm	July to January	OE-23	Mirpur	25.504108° N, 69.037589° E	Rizwan & Jamil	ISL-133427	63	Mirpur/Sindh
13.	Pergularia daemia (Forssk.) Chiov.	October to November	PD-14	Jehlum	32.951902° N, 73.689400° E	Rizwan	ISL-133429	768	Jehlum/Punjab
14.	Periploca aphylla Decne.	June to September	PA-05	Sakesar	32.558860° N, 71.913981° E	Rizwan	ISL-133414	5,092	Khushab/Punjab
15.	Plumeria rubra L.	July to October	PR-08	Mirpur	25.359219° N, 69.143117° E	Rizwan & Jamil	ISL-133421	59	Mirpur/Sindh
16.	Tabernaemontana divaricata (L.) R.Br. ex Roem. & Schult.	August to September	TD-04	GHS	32.577587° N, 71.537370° E	Rizwan	133423	650	Mianwali/Punjab
17.	Vincetoxicum spirale (Forssk.) D.Z.Li	June to August	VS-07	Daud Khail	32.888711° N, 71.614760° E	Rizwan	133420	692	Mianwali/Punjab
18.	Dregea volubilis (L.f.) Benth. ex Hook.f	July to August	WV-02	QAU	33.746286° N, 73.138156° E	Rizwan	133417	2,031	Islamabad

Qualitative pollen micromorphological characters of Apocynaceous taxa_

Sr. No.	Apocynaceous taxa	Size	Pollen type	Pollen shape	Polar view (Amb)	Dispersal unit	Aperture orientation	Exine sculpturing
1.	Allamanda cathartica L.	Medium	Tricolporate	Sub-spheroidal	Triangular (convex)	Monad	Colporate	Reticulate
2.	Alstonia scholaris (L.) R. Br.	Small	Tricolporate	Sub-spheroidal	Lobate & isoplar	Monad	Scabrate	Psilate to perforate
3.	Carissa macrocarpa (Eckl.) A. DC.	Medium	Tricolporate	Oblate spheroidal	Circular & isoplar	Monad	Colporate	Perforate to regulate
4.	Carissa spinarum L.	Medium	Tricolporate	Oblate spheroidal	Lobate & isopolar	Monad	Colporate	Perforate, psilate to regulate
5.	Cascabela thevetia (L.) Lippold	Very large	Tricolporate	Prolate spheroidal	Lobate	Monad	Colporus	Microreticulate to perforate
6.	Catharanthus roseus (L.) G. Don	Large	Tricolporate	Oblate spheroidal	Irregular	Monad	Colporate	Perforate to scabrate
7.	Cryptolepis dubia (Burm.f.). M.R. Almeida	Small to medium	Tetrad	Rhombodial	Rhombodial	Tetrad		Reticulate
8.	Nerium oleander L.	Medium	Tetraporate	Oblate spheroidal	Circular	Monad	Porate	Psilate
9.	Periploca aphylla Decne.	Small to large	Tetrad	Oblong	Rhomboidal	Tetrad	Porate	Psilate
10.	Plumeria rubra L.	Medium	Tricolporate	Prolate spheroidal	Lobate & isoploar	Monad	Colporate	Psilate to scabrate
11.	Tabernaemontana divaricata (L.) R.Br. ex Roem. & Schult.	Medium	Tricolpate	Oblate spheroidal	Circular & isopolar	Monad	Colpoate	Perforate

Pollen ferity and sterility count among Apocynaceous species_

Sr. No.	Apocynaceous taxa	Fertile pollen/pollinia	Sterile pollen/pollinia	Fertility%	Sterility%
1.	Allamanda cathartica L.	26	12	68.42	31.57
2.	Alstonia scholaris (L.) R.Br.	18	06	75.00	25.00
3.	Asclepias curassavica L.	05	01	83.33	16.66
4.	Calotropis procera (Aiton) Dryand.	08	04	66.66	33.33
5.	Carissa macrocarpa (Eckl.) A. DC.	23	09	71.87	28.12
6.	Carissa spinarum L.	14	04	77.77	22.22
7.	Cascabela thevetia (L.) Lippold	21	08	72.41	27.58
8.	Catharanthus roseus (L.) G. Don	14	06	70.00	30.00
9.	Cryptolepis dubia (Burm.f.) M.R. Almeida	12	02	85.71	14.28
10.	Leptadenia pyrotechnica (Forssk.) Decne.	08	02	80.00	20.00
11.	Nerium oleander L.	09	02	81.81	18.18
12.	Oxystelma esculentum (L. f.) Sm	10	03	76.92	23.07
13.	Pergularia daemia (Forssk.) Chiov.	05	02	71.42	28.57
14.	Periploca aphylla Decne.	11	04	73.33	26.66
15.	Plumeria rubra L.	11	03	78.57	21.42
16.	Tabernaemontana divaricata (L.) R. Br. ex Roem. & Schult.	16	05	76.19	23.80
17.	Vincetoxicum spirale (Forssk.) D.Z. Li	06	02	75.00	25.00
18.	Dregea volubilis (L.f.) Benth. ex Hook.f	07	03	70.00	30.00

PCA % variance loadings for the Apocynaceous pollen_

PC	Eigenvalue	% variance
1	2.35994	39.332
2	1.53998	25.666
3	1.0319	17.198
4	0.82796	13.799
5	0.239496	3.9916
6	0.000728	0.012128

j_fhort-2023-0034_tab_008

1+ Pollen tetraporate, oblate-spheroidal, psilate ornamentation..................	N. oleander
− Pollen tetrad, tricolporate......................	2
2 + Tetrad, oblong, psilate sculpturing....................	P. aphylla
2 − Tetrad, rhomboidal, reticulate sculpturing.................	C. dubia
3 + Tricolporate, oblate spheroidal, perforate-regulate exine............	C. macrocarpa
3 − Tricolporate, lobate, psilate-regulate sculpturing.............	C. spinarum
4 + Oblate-spheroidal, tricolporate, perforate-scabrate.................	C. roseus
4 − Colporate, perforate exine sculpturing....................	T. divaricata
5 + Sub-spheroidal, reticulate exine, tricolporate...............	A. cathartica
5 − Lobate, psilate-perforate exine.................	A. scholaris
6 + Prolate-spheroidal, tricolporate, psilate to scabrate exine.............	P. alba
6 − Colporus, micro-reticulate exine, lobate..................	C. thevetia