Seed Germination of Rhododendron chapmanii: Influence of Light and Temperature

Arocha, Luis O.; Blazich, Frank A.; Warren, Stuart L.; Thetford, Mack; Berry, James B.

doi:10.24266/0738-2898-17.4.193

Cited by 5 publications

(3 citation statements)

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“…Other studies have indicated that photoperiod regulates seed germination of Rhododendron chapmanii A. (Arocha et al 1999), hyssop loosestrife (Lythrum hyssopifolia L.), and corn poppy [Parapholis incurva (L.) Hubbard] (Noe and Zedler 2000) (see also Baskin C. C. and Baskin J. M. 1998;Black 1967). Densmore (1997) found that a combination of short day length and stratification requirement prevents germination of Alaskan plant seed in the fall.…”

Section: Modeling Weed Emergencementioning

confidence: 99%

Seasonal changes in annual bluegrass (Poa annua) germinability and emergence

Shem-Tov

Fennimore

2003

Weed Science

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The seasonal emergence characteristics and seedbank ecology of annual bluegrass were evaluated in a vegetable field in the central coast of California. The emergence and germinability of annual bluegrass were monitored continuously for over 3 yr to detect seasonal variation in weed emergence. Weed emergence and seedbank densities were measured every 45 d for 41 mo. Weed emergence was monitored simultaneously in the field and in a growth chamber that was adjusted seasonally for day length and temperature. Samples were incubated in the growth chamber for 45 d and then elutriated to measure remaining viable ungerminated caryopses and relative germination potential. Seedbank densities ranged from 2,000 to 20,000 caryopses m−2 during the study period. Weed emergence and germinability were highest from October to November and lowest from March to July. Emergence from soils collected in the spring and fall and incubated under both spring and fall conditions in the growth chamber indicated that seed dormancy state determines germinability rather than environmental conditions during incubation. Soil samples collected in the spring had no emergence (<1%) when incubated under spring or fall conditions, whereas samples collected in the fall had high emergence (>95%) under both spring and fall conditions. A waveform regression fit the repeated emergence pattern with a cycle length of 364 d (365 d for the growth chamber). This model predicted that weed emergence would peak on November 5 and be lowest on June 20. A survey of organic vegetable fields found that caryopses were more common in soils with higher clay content than in lighter soils (R 2 = 0.77, P = 0.02). Our data suggest that annual bluegrass is more likely to emerge when the soil is wet during winter. The timing and location of annual bluegrass emergence may increase the probability of reproductive success during periods when seasonal rains and wet conditions limit tillage, weeding activities, and competition with other weeds.

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Section: Modeling Weed Emergencementioning

confidence: 99%

Seasonal changes in annual bluegrass (Poa annua) germinability and emergence

Shem-Tov

Fennimore

2003

Weed Science

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“…The average 1000-seed weight of Rhododendron species in Turkey was reported between 0.142 g and 0.067 g (Altun, 2011). The seeds do not need any chilling requirements due to the higher germination and emergence rates, depending upon species (Ryabova and Zueva, 1993;Sakharova, 1993;Arocha et al, 1999;Glenn et al, 1999;Basnet, 2005;Vologdina, 2006;Altun, 2011). Seeds need light to germinate (Vologdina, 2006); therefore, seeds must be sown superficially during planting and not be covered.…”

Section: Introductionmentioning

confidence: 99%

Effects of seed sowing methods on emergence and seedling growth of some Rhododendron species

Yazici¹,

Altun²

2021

Anadolu Journal of Agricultural Sciences

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This study was conducted to determine the effects of different seed sowing methods on emergence rate, densities of seedling emergence and seedling growth of five Rhododendron species (R. ponticum L., R. luteum Sweet, R. caucasicum Pallas, R. simirnowii Trautv and R. ungernii Trautv). Four different sowing methods were tested, manual sowing in a row (control), mixing with plant agar, mixing with Murashige and Skoog Basal medium (MS) and mixing with stream sand. The highest seed emergence rates were obtained by manual sowing in a row (control) with R. ponticum species (76 %) followed by R. luteum (66.6 %), R. smirnowii (55.33 %), R. ungernii (24 %) and R. caucasicum (15.33 %), respectively. Similarly, the values closest to ideal seed distribution for homogenous seedling density were obtained by hand-sowing in row method. The highest seedling height was obtained in MS medium with R. ponticum (2.11 cm), followed by R. luteum (3.08 cm), R. smirnowii (4.07 cm), and R. ungernii (1.39 cm), while the effect of the seeding method on seedling growth of R. caucasicum species was not significant. To conclude, the best homogeneous distribution of seedling emergence densities of Rhododendron species was obtained by a controlled manual seeding method. However, the seed sowing with MS mixing increased significantly seedling growth in all Rhododendron species.Farklı tohum ekim yöntemlerinin orman gülü (Rhododendron ssp.) tohumlarının çıkışları ve fide gelişimi üzerine etkileri Keywords: Rhododendron Seed Sowing medium MS Agar Sand ÖZET Bu araştırma, orman gülü türlerinin (Rhododednron ponticum L., R. luteum Sweet, R. caucasicum Pallas, R. simirnovii Trautv ve R. ungernii Trautv) tohumlarınına uygulanan farklı tohum ekim yöntemlerinin çıkış süresi, fide çıkış sıklıkları ve bitki büyümesine olan etkilerini belirlemek amacıyla yürütülmüştür. Ekim yöntemi olarak, elle sıraya ekme (kontrol), plant agar ile karıştırma, MS ile karıştırma ve dere kumu ile karıştırma olmak üzere dört farklı tohum ekim yöntemi denenmiştir.

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“…Rhododendrons normally produce numerous amounts of seeds (Cox, 1990;Romancier, 1970) [12,48] however; viable seeds are not always available on a yearly basis. They are extremely small and size can vary greatly among species (Arocha et al, 1999;Blazich et al, 1991;Glenn et al, 1998;Olson, 1974) [3,7,20,40] . R. arboreum, locally known as 'Burans', is amongst highly valued wild edible tree growing in hills of HP state found distributed in Shimla, Solan, Kinnaur, Mandi, Kangra, Kullu, Sirmour and Chamba districts of Himachal Pradesh (Kharwal and Rawat, 2013) [25] .…”

Section: Introductionmentioning

confidence: 99%

Seed Germiability, viability and longevity of Rhododendron arboreum var. arboreum Sm.

Kumar¹,

Sharma²

2020

Int. J. Chem. Stud.

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The present study has been undertaken with the objective to assess the germiability, viability and longevity of R. arboreum seeds at laboratory conditions as these factors are very important to promote the process of natural regeneration of species in wild which ultimately responsible for the better survival and existence of species. The seeds for experiment were collected from Craignaino forest in Mashobara Range of Shimla forest division. Seed parameters like Germination per cent, germination energy and germination value were calculated to test the germiability from the freshly collected seeds continuously for the period of six years. Seed viability was assessed through germination method and TTZ (Tetrazolium salt) method. A storage trial was designed by using polythene bags and cloth bags as a medium of storage of seeds, to check the longevity of the seeds under three different temperature gradients (deep freezer, Multi cooling chamber and normal room temperature). The results are diverse, having common observation with higher viability in freshly collected seeds as compared to the previous years. The overall Results showed tendency of decline in germiability as well as loss in viability over a period of time. The deep freeze (-20°C) is the best suitable temperature gradient for the storage of R. arboreum seeds as the maximum viability of the seeds has been observed in this medium with the 50% decline in viability in the period of 3 years.

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Seed Germination of Rhododendron chapmanii: Influence of Light and Temperature

Cited by 5 publications

References 0 publications

Seasonal changes in annual bluegrass (Poa annua) germinability and emergence

Seasonal changes in annual bluegrass (Poa annua) germinability and emergence

Effects of seed sowing methods on emergence and seedling growth of some Rhododendron species

Seed Germiability, viability and longevity of Rhododendron arboreum var. arboreum Sm.

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