Action of Phytochrome During Prechilling of Amaranthus retroflexus L. Seeds.
نویسندگان
چکیده
Dark germination of Amaranthus retroflexus L. seeds at 35 degrees increased after several days of prechilling at 20 degrees or lower. Irradiation with far-red light for short periods during the early hours of a prechilling period at 10 degrees inhibited subsequent dark germination at 35 degrees . The inhibition was completely reversible with red light. Far-red irradiation in the latter part of the prechilling period was less effective. Increased dark germination of A. retroflexus seeds following a prechilling period at 20 degrees or less is attributed to action of preexistent P(FR), the far-red absorbing form of phytochrome, within the seeds. Inactivation of P(FR) was found to proceed ca. 4 times more rapidly at 25 degrees than at 20 degrees . Failure of imbibition temperatures above 20 degrees to increase dark germination of A. retroflexus seeds is attributed to the rapid thermal reversion of pre-existent P(FR). We suggest that the action of prechilling (layering) on many other seed kinds arises in a similar way.
منابع مشابه
Rehydration of Phytochrome in Imbibing Seeds of Amaranthus retroflexus L.
It is commonly recognized that light-sensitive seeds require a period of imbibition before full promotion of germination by a light stimulus can be attained. Yet little work describes the nature of these preliminary events. Of the several major limitations that may be involved, clearly the rehydration (or activation) of phytochrome and the system with which it interacts are the chief ones to co...
متن کاملChanges in Phytochrome Expressed by Germination of Amaranthus retroflexus L. Seeds.
Effects of red (600 to 680 nanometers) and far red (700 to 760 nanometers) irradiances on Amaranthus retroflexus L. seeds indicate that synthesis of phytochrome in the red-absorbing form takes place in water-imbibed nongerminating seeds at 35 C. After 96 hours in darkness, conversion of about 0.10% phytochrome to the far red-absorbing form induces 50% germination. Continuous far red radiation a...
متن کاملDependence of phytochrome action in seeds on membrane organization.
Germination of Amaranthus retroflexus L. seeds imbibed at 40 C is enhanced by establishing the active form of phytochrome before a reduction in temperature to <32 C. The half-time for effectiveness of the lower temperature is about 8 min at 15 C. Isolated membrane fragments of A. retroflexus seeds associated with the fluorescent probe 1,8-anilino-naphthalene sulfonate (ANS) increase in structur...
متن کاملOpposing Actions of Light in Seed Germination of Poa pratensis and Amaranthus arenicola.
Action spectra were measured for suppression of germination of Poa pratensis L. and Amaranthus arenicola I. M. Johnston seed under prolonged or continuous irradiation. The action maxima for both types of seeds are near 720 nm. The maxima are unchanged in position or magnitude in the presence of radiation in the region of 600 to 670 nm adequate to maintain phytochrome predominantly in the far-re...
متن کاملEnhanced Phytochrome Sensitivity and Its Reversal in Amaranthus albus Seeds.
Seed of Amaranthus alus L. develop an enhanced sensitivity to the farred absorbing form of phytochrome after prolonged imbibition at temperatures >32 degrees C. The enhanced sensitivity developed at 40 degrees C could be reversed by subsequent treatment at 20 degrees C and similarly reestablished by repeating a 40 degrees C treatment. It is concluded that relative sensitivity to the far-red abs...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Plant physiology
دوره 44 6 شماره
صفحات -
تاریخ انتشار 1969