SUMMARY
DELAY OF GERMINATION 1 is a key regulator of dormancy in flowering plants before seed germination. Bryophytes develop haploid spores with an analogous function to seeds. Here, we investigate ...whether DOG1 function during germination is conserved between bryophytes and flowering plants and analyse the underlying mechanism of DOG1 action in the moss Physcomitrium patens. Phylogenetic and in silico expression analyses were performed to identify and characterise DOG1 domain‐containing genes in P. patens. Germination assays were performed to characterise a Ppdog1‐like1 mutant, and replacement with AtDOG1 was carried out. Yeast two‐hybrid assays were used to test the interaction of the PpDOG1‐like protein with DELLA proteins from P. patens and A. thaliana. P. patens possesses nine DOG1 domain‐containing genes. The DOG1‐like protein PpDOG1‐L1 (Pp3c3_9650) interacts with PpDELLAa and PpDELLAb and the A. thaliana DELLA protein AtRGA in yeast. Protein truncations revealed the DOG1 domain as necessary and sufficient for interaction with PpDELLA proteins. Spores of Ppdog1‐l1 mutant germinate faster than wild type, but replacement with AtDOG1 reverses this effect. Our data demonstrate a role for the PpDOG1‐LIKE1 protein in moss spore germination, possibly alongside PpDELLAs. This suggests a conserved DOG1 domain function in germination, albeit with differential adaptation of regulatory networks in seed and spore germination.
Significance Statement
Seed and spore germination are considered analogous because they occur in the sporophyte (seed plants) and gametophyte (bryophytes). Here we show that an ortholog of Arabidopsis DELAY OF GERMINATION 1 (DOG1) controls spore germination in the moss P. patens, suggesting deep evolutionary conservation of germination control of reproductive diaspores.
The aim of this research was to determine the sample size (number of plants) necessary to estimate the average plant height, collar diameter and relation plant height/collar diameter of seedlings ...pecan (Carya illinoinensis) and to verify the variability of the sample size among treatments of overcoming seed dormancy. It was evaluated 12 treatments of overcoming seed dormancy and at 98 days after sowing it was measured the plant height (H) and collar diameter (D) and calculated the relation plant height/collar diameter (HD). Measures of central tendency and variability were calculated, the normality and homogeneity of variances were verified and sample size was calculated. The sample size to evaluate H, D e HD is dependent on treatments of overcoming seed dormancy. Sixty-three plants enough to predict the average of H, D and HD seedlings pecan, with an estimation error equal to 10% of estimated average, with a degree confidence of 95%. Key words: Carya illinoinensis, experimental planning, sampling. O objetivo deste trabalho foi determinar o tamanho de amostra (numero de plantas) necessario para a estimacao da media de altura de planta, do diametro do coleto e da relacao altura de planta/diametro do coleto de mudas de nogueira-peca (Carya illinoinensis) e verificar a variabilidade do tamanho de amostra entre tratamentos de superacao de dormencia de sementes. Foram avaliados 12 tratamentos de superacao de dormencia de sementes e, aos 98 dias apos a semeadura, foram mensurados os caracteres altura de planta (H) e diametro do coleto (D), e calculada a relacao altura de planta/diametro do coleto (HD). Foram calculadas medidas de tendencia central e de variabilidade, verificadas a normalidade e a homogeneidade de variancias e calculado o tamanho de amostra. O tamanho de amostra para avaliar H, D e HD de mudas de nogueira-peca e dependente do tratamento para superacao de dormencia de sementes. Sessenta e tres plantas sao suficientes para a estimacao da media de H, do D e da HD de mudas de nogueira-peca, para erro de estimacao de 10% da media estimada, com grau de confianca de 95%. Palavras-chave: Carya illinoinensis, planejamento experimental, amostragem.
The aim of this research was to determine the sample size (number of plants) necessary to estimate the average plant height, collar diameter and relation plant height/collar diameter of seedlings ...pecan (Carya illinoinensis) and to verify the variability of the sample size among treatments of overcoming seed dormancy. It was evaluated 12 treatments of overcoming seed dormancy and at 98 days after sowing it was measured the plant height (H) and collar diameter (D) and calculated the relation plant height/collar diameter (HD). Measures of central tendency and variability were calculated, the normality and homogeneity of variances were verified and sample size was calculated. The sample size to evaluate H, D e HD is dependent on treatments of overcoming seed dormancy. Sixty-three plants enough to predict the average of H, D and HD seedlings pecan, with an estimation error equal to 10% of estimated average, with a degree confidence of 95%.
Los gametófitos entre las Pteridaceae están bastante bien conocidos, si bien hay aún un buen número de especies por describir, entr las que se encuentra Doryopteris triphylla, un miembro del clado de ...los Cheilanthoides. El principal objetivo de este trabajo es describir la fase gametofítica de D. triphylla. Para ello, se sembraron esporas de diferentes esporófitos de varias localidades diferentes, en cultivos multispóricos. A lo largo del desarrollo de los protalos se realizaron observaciones in vivo de los principales eventos de desarrollo y reproducción. La germinación sigue el modelo Vittaria y el subsiguiente proceso de desarrollo se ajusta al tipo Adiantum. Los gametófitos adultos cordados producen órganos sexuales normales en protalos unisexuales. Los gametófitos de D. triphylla exhiben algunas peculiaridades, como por ejemplo la división longitudinal de la célula apical, la forma rectangular de la primera célula meristemática y el hecho de que los protalos arquegoniados aparecen mucho tiempo antes que los anteridiados.
The seasonal timing of seed germination determines a plant’s realized environmental niche, and is important for adaptation to climate. The timing of seasonal germination depends on patterns of seed ...dormancy release or induction by cold and interacts with flowering-time variation to construct different seasonal life histories. To characterize the genetic basis and climatic associations of natural variation in seed chilling responses and associated life-history syndromes, we selected 559 fully sequenced accessions of the model annual species Arabidopsis thaliana fromacross a wide climate range and scored each for seed germination across a range of 13 cold stratification treatments, as well as the timing of flowering and senescence. Germination strategies varied continuously along 2 major axes: 1) Overall germination fraction and 2) induction vs. release of dormancy by cold. Natural variation in seed responses to chilling was correlated with flowering time and senescence to create a range of seasonal life-history syndromes. Genome-wide association identified several loci associated with natural variation in seed chilling responses, including a known functional polymorphism in the selfbinding domain of the candidate gene DOG1. A phylogeny of DOG1 haplotypes revealed ancient divergence of these functional variants associated with periods of Pleistocene climate change, and Gradient Forest analysis showed that allele turnover of candidate SNPswas significantly associated with climate gradients. These results provide evidence that A. thaliana’s germination niche and correlated life-history syndromes are shaped by past climate cycles, as well as local adaptation to contemporary climate.
Channel Island foxes Bartel, Savannah L; Schamel, Juliann T; Parrino, Bridget A ...
Western North American naturalist,
06/2023, Volume:
83, Issue:
1
Journal Article
Peer reviewed
Mammals that consume fleshy fruit and deposit viable seeds in their scat can be important agents of seed dispersal for plants. Despite the knowledge that the island fox (Urocyon littoralis) consumes ...large quantities of fleshy fruits, it is unknown whether seeds survive digestion by island foxes and are able to germinate. In order to evaluate whether island foxes are agents of viable seed dispersal on the channel islands, we collected island fox scat on santa cruz Island in February 2021 and conducted germination assays on digested seeds found in scat. We compared the germinability and germination rates of 200 toyon (Heteromeles arbutifolia) seeds digested by island foxes with that of 100 undigested seeds that were manually removed from toyon fruit collected in the same location and time period as scat collection. over the course of 25 d, 32% of the seeds digested by island foxes germinated, and 61% of the undigested seeds germinated. Seeds digested by foxes germinated at slower rates than undigested seeds, and there was a 21.4% wider range of germination times for digested seeds than for undigested seeds. There was also substantial variation in the probability of seed germination among scat samples, ranging from 0% to 100%, indicating that the quality of dispersal by island foxes may depend upon individual fox traits or an individual fox's environment. These results show that island foxes are effective dispersal agents of toyon seeds, but the benefits of being dispersed by foxes come at a cost of reduced germination. Environmental changes on the Channel Islands that modify the diet and space use of island foxes could therefore affect dispersal and recruitment of island plants.
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