Ultrastructural study on degeneration of tapetum in anther of snap bean ( Phaseolus vulgaris L.) under heat stress

Abstract

Pollen sterility was induced by heat stress applied about 10 days before flowering in the snap bean Phaseolus vulgaris L. Cytohistological changes in the tapetum during early development of the anther were studied to identify the tissues most sensitive to high temperature stress. The first distinct structural abnormalities were detected in the distribution pattern of the rough endoplasmic reticulum (RER) in the tapetum at the early microspore stage under high temperature conditions. Stacks of RER were frequently observed in the tapetum under optimal conditions, but rarely occurred under high temperature conditions. Various patterns of endoplasmic reticulum (ER) arrangement -linear, wavy, looped or circular -were observed in the tapetum. Two types of circular ER were observed at the microspore stage under high temperature conditions, RER with ribosomes on the surface and smooth endoplasmic reticulum (SER) lacking ribosomes. The tapetum underwent degenerative changes under high temperature conditions earlier than under optimal conditions. The structural abnormalities of the microspore were associated with tapetal degeneration. We concluded that high air temperature affected the ER structure and blocked its function in the tapetum, and then induced earlier than usual degeneration of tapetum. Pollen sterility is associated with tapetal degeneration. Materials and methodsEighty snap bean plants (Phaseolus vulgaris L. cv. Kentucky Wonder) were grown 25 cm apart in four rows, each 1 m wide × 5 m long, in a net house from 18 April at JIRCAS Okinawa Subtropical Station in 1997. About 50 flower buds of different sizes were collected randomly from the plants on 28 May (optimum conditions). The maximum temperature that day was 28.6°C, the minimum 24.4°C and the average 26.2°C. Average air temperature in May was 25.8°C.

Effect of high temperature on the reproductive development of chickpea genotypes under controlled environments

“…Anther indehiscence occurs in cowpea (Vigna unguiculata L.) due to heat stress (33/30˚C) and is associated with degeneration of tapetal layer (Ahmed et al 1992). The degeneration of tapetum cells was also found in common bean (Phaseolus vulgaris L.) at 33/29˚C (Suzuki et al 2001), resulting in premature pollen development within the anther during early development. High temperature (33/27˚C) before anthesis can also cause anther indehiscence and pollen sterility in common beans (Gross and Kigel, 1994).…”

Sugar and Auxin Signaling Pathways Respond to High-Temperature Stress during Anther Development as Revealed by Transcript Profiling Analysis in Cotton

“…During this process, the young microspore stage has been reported to be the most sensitive to temperature changes. In the tapetum, the innermost cell layer of the anther is known to be the most sensitive cell layer to environmental stress during the young microspore stage (Suzuki et al, 2001). Additionally, some researchers have reported that the flowering stage and the young microspore stage of rice were most sensitive to HT stress, showing poor anther dehiscence during flowering and disrupted tapetum functions during young microspore development (Sato et al, 2002;Endo et al, 2009).…”

Influence Of Temperature Shift After Flowering on Dry Matter Partitioning In Two Cultivars of Snap Bean (Phaseolus Vulgaris)That Differ In Heat Tolerance

“…Cultivar Haibushi has been selected for its heat tolerance (Nakano et al, 1997) and produces higher pod yield and maintains higher leaf water content than Kentucky Wonder after exposure to high temperature (Omae et al, 2004(Omae et al, , 2005bKumar et al, 2005). The pod yield is also directly affected by high temperature due to the lack of pollination, and increased senescence and abscission of flowers and young pods (Suzuki et al, 2001a). Cultivars Haibushi and Kentucky Wonder did not differ in pollen fertility but the former showed higher pod setting and retention than the latter (Omae et al, 2005a).…”