Differences in in vitro pollen germination and pollen tube growth of coconut (Cocos nucifera L.) cultivars in response to high temperature stress

Between February 2018 and April 2018, flowers were collected from eight Rosaceae species. Flowers were kept in a freezer at −20 °C for three freezing times (Treatment 1, two months; Treatment 2, four months; Treatment 3, six months). After extracting pollen, in vitro germination was induced in a culture medium and incubated at six different temperatures for 72 h. The percentage of pollen germination, average pollen tube length and maximum pollen tube length were measured. Pollen germination was maximum for all species between 15 °C and 30 °C. Cydonia oblonga, Malus sylvestris, Prunus avium, Prunus domestica, Prunus dulcis, Prunus persica and Pyrus communis obtained 30–52% pollen germination between 15 °C and 20 °C. Prunus cerasifera had 40% pollen germination at 30 °C. All species studied reached the maximum pollen tube length between 10 °C and 25 °C. Germination did not change significantly for any of the species with freezing time, but we found significant differences in the three parameters measured between treatments. The highest germination percentages were obtained in Treatment 2 (four months frozen at −20 °C), while the maximum pollen tube length was reached in Treatment 1 (two months frozen at −20 °C). According to our results, freezing time affected the germination-temperature patterns. This could indicate that studies on the effect of temperature on pollen germination should always be carried out with fresh pollen to obtain more conclusive data.

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“…(Acar & Kakani, 2010), longan ( Dimocarpus longan Lour. ; Pham, Herrero & Hormaza, 2015) and coconut ( Cocos nucifera L.; Hebbar et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Effect of temperature on pollen germination for several Rosaceae species: influence of freezing conservation time on germination patterns

Beltrán

Valls

Cebrián

et al. 2019

PeerJ

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“…Studies on almonds [ 22 ], coconut [ 53 ], cotton [ 21 ], and groundnut [ 20 ] have shown that cultivars can have different cardinal temperatures for pollen germination and tube growth. The variation in cardinal temperatures could explain some of the cultivar differences.…”

Section: Discussionmentioning

confidence: 99%

Novel Metrics to Characterize In Vitro Pollen Tube Growth Performance of Apple Cultivars

Roeder

Serra

Musacchi

2021

Plants

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In vitro germination assays are frequently used in screening trials to evaluate the pollen viability of pollinizers. To be effective, screening trials must have defined threshold criteria, from which individuals can then be assessed. However, despite decades of research on pollen viability, no established threshold is available to categorize apple cultivars based on their in vitro pollen tube lengths. This study aimed to identify and characterize the subgroups of cultivars based on their pollen tube growth performance. In vitro pollen tube lengths of 41 individuals were determined by incubating samples on artificial germination media at 15 and 25 °C. A six-number summary statistic was calculated, and hierarchical clustering on principal component (HCPC) analysis was used to determine and characterize subgroups. Furthermore, a decision tree model was used to predict class membership for future datasets. HCPC analysis partitioned the 41 individuals into three subgroups with different performances. The decision tree quickly predicted the cluster membership based on the second quartile at 15 °C and the third quartile at 25 °C. The thresholds from the decision tree can be used to characterize new observations. The use of the methods will be demonstrated using a case study with 29 apple accessions.

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“…The germination of Prunus avium pollen grains was reduced at 30 °C, with significant differences among different genotypes (Hedhly et al 2005). Likewise, different coconut varieties respond differently to high‐temperature stress, and the pollen germination rate of these coconut varieties decreased at temperatures above 30 °C (Hebbar et al 2018). This experiment showed that when the ambient temperature was 35 °C and the corolla was removed, pollen germination was significantly reduced, resulting in failure of fertilization.…”

Section: Discussionmentioning

confidence: 99%

Doubly guaranteed mechanism for pollination and fertilization in Ipomoea purpurea

Liu

Gui²,

Sun

et al. 2020

Plant Biol J

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• Flowers, the reproductive organs of angiosperms, show a high degree of diversity in morphological structure and flowering habit to ensure pollination and fertilization of the plants. Effect of flower movement on pollination and fertilization was investigated in Ipomoea purpurea (Convolvulaceae) in this study. • Fluorescence microscopy was used to observe the germination of pollen grains at different temperatures. • From 04:00 to 06:00 h, the stigma was taller than the filaments, so that self-pollination could not occur, and cross-pollination was carried out by insects. Pollen grains germinated rapidly after falling on the stigma; the pollen tube reached the ovule to complete fertilization after 2-3 h. From 07:00 to 09:00 h, filaments of two stamens grew rapidly and reached the same height as the stigma, thus allowing self-crossing. But at this time, the ambient temperature was already high and was not conducive to the germination of pollen grains. The corolla closed, forming an inverted bell shape, where the inner microenvironment ensured completion of pollen germination and fertilization. • Preferential cross-pollination and delayed self-crossing of I. purpurea provided a doubly guaranteed mechanism for pollination and fertilization, facilitating its adaptation to a high temperature climate.

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Differences in in vitro pollen germination and pollen tube growth of coconut (Cocos nucifera L.) cultivars in response to high temperature stress

Cited by 44 publications

References 35 publications

Effect of temperature on pollen germination for several Rosaceae species: influence of freezing conservation time on germination patterns

Effect of temperature on pollen germination for several Rosaceae species: influence of freezing conservation time on germination patterns

Novel Metrics to Characterize In Vitro Pollen Tube Growth Performance of Apple Cultivars

Doubly guaranteed mechanism for pollination and fertilization in Ipomoea purpurea

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