Burial conditions affect light responses of Datura ferox seeds
Burial conditions affect light responses of Datura ferox seeds
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DOI：
10.1017/s0960258500004384
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发表时间：
1998-12-01
影响因子：
2.1
通讯作者：
Casal, JJ
中科院分区：
文献类型：
--
作者：
Botto, JF;Sánchez, RA;Casal, JJ
以曼陀罗种子为试材，研究了埋藏种子在红光（R）、远红光（FR）和黑暗条件下的萌发规律。种子在冬季埋藏时处于深度休眠状态。三个月后（春天），挖出的种子开始对R脉冲作出反应。夏季温度没有诱导二次休眠。在第二年的冬季，种子发芽后的R脉冲进一步增加，然而，发芽后的FR脉冲或在黑暗中也增加，并达到接近R的值。种子萌发后的R或FR脉冲和在黑暗中的变化进行了研究，在析因设计实验，结合不同的埋深（0.5，5和10厘米），植被的存在（有或没有植被冠层），和日期的挖掘（4或7个月后埋葬）。放置在0.5cm深度的种子在任何光处理下都不发芽。一个非常高的光敏感性，表明由FR脉冲相比，黑暗的发芽促进，表现出只有在种子埋在5厘米的土壤中没有植被。一个典型的R/FR可逆的反应，观察到在5和10厘米，几乎所有的情况下埋葬的种子挖出，除了在土壤中没有植被，在10厘米深，在夏末，即使黑暗的控制表现出高发芽。因此，D.在第一年的春天，第一步和第二步在随后的冬天。这一过程并不明显受夏季气温的控制。对光的高度敏感性的获得取决于植被覆盖和埋葬深度，因此预计会受到农业实践的影响。
The dormancy pattern of buried seeds of Datura ferox was studied by testing germination responses to red light (R), far-red light (FR) or darkness after exhumation at regular time intervals. The seeds were deeply dormant at the time of burial in winter. After three months (spring), exhumed seeds began to respond to an R pulse. Summer temperatures did not induce secondary dormancy. During winter of the second year, seed germination after an R pulse increased further; however, germination after an FR pulse or in darkness also increased and reached values close to R. Changes in seed germination after an R or an FR pulse and in darkness were studied in a factorial design experiment, combining different depths of burial (0.5, 5 and 10 cm), presence of vegetation (with or without vegetation canopies), and date of exhumation (4 or 7 months after burial). The seeds placed at 0.5 cm depth did not germinate in any light treatment. A very high sensitivity to light, indicated by the promotion of germination by an FR pulse compared to darkness, was exhibited only in seeds buried at 5 cm in a soil without vegetation. A typical R/FR reversible response was observed in seeds exhumed at 5 and 10 cm in almost all situations of burial; except in a soil without vegetation, at 10 cm depth, in late summer when even dark controls showed high germination. It is concluded that buried seeds of D. ferox are released from dormancy in two steps, the first step during the spring of the first year and the second step during the subsequent winter. This process is not obviously controlled by summer temperatures. The acquisition of a very high sensitivity to light depends on vegetation cover and depth of burial, and thus it is predicted to be affected by agricultural practices.